Wikipedia - User contributions [en]

Turnover number

2010-04-10T15:04:55Z

Su-no-G: +ja

{{Unreferenced stub|auto=yes|date=December 2009}}
'''Turnover number''' has two related meanings:

In [[enzymology]], turnover number (also termed '''kcat''') is defined as the maximum number of molecules of [[Substrate (biochemistry)|substrate]] that an [[enzyme]] can convert to product per [[catalytic site]] per unit of time and can be calculated as follows: kcat = Vmax/[E]T (see [[Michaelis-Menten kinetics]]). For example, [[carbonic anhydrase]] has a turnover number of 400,000 to 600,000 s−1, which means that each carbonic anhydrase molecule can produce up to 600,000 molecules of product ([[bicarbonate]] ions) ''per second''.<ref name=Hagen>{{ cite book |author=Hagen J |title=Industrial Catalysis: A Practical Approach |year=2006 |publisher=Wiley-VCH |location=Weinheim, Germany }}</ref>

In other chemical fields, such as [[organometallic chemistry|organometallic]] [[catalysis]], turnover number (abbreviated ''TON'') is used with a slightly different meaning: the number of moles of substrate that a mole of catalyst can convert before becoming inactivated. An ideal catalyst would have an infinite turnover number in this sense, because it wouldn't ever be consumed, but in actual practice one often sees turnover numbers which go from 100 to a million or more. The term '''turnover frequency''' (abbreviated ''TOF'') is used to refer to the turnover per unit time, as in enzymology. For most relevant industrial applications, the turnover frequency is in the range of 10−2 - 102 s−1 (enzymes 103 - 107 s−1).[1]

==Turnover number of acetylcholinesterase==

[[Acetylcholinesterase]] (AChE) may be one of the fastest enzymes. It hydrolyzes [[acetylcholine]] to [[choline]] and an [[acetate]] group. One of the earliest values of the turnover number was 3 x 107 (molecules of acetylcholine) per minute per molecule of enzyme.<ref name=Rothenberg>{{ cite journal |author=Rothenberg MA, Nachmansohn D |title= |journal=J Biol Chem. |volume=168 |pages=223 |year=1947 }}</ref> A more recent value at 25°C, pH = 7.0, acetylcholine concentration of 2.5 x 10-3 M, was found to be 7.4 x 105 min-1.<ref name=Wilson>{{ cite journal |author=Wilson IB, Harrison MA |title=Turnover number of acetylcholinesterase |journal=J Biol Chem. |month=Aug |year=1961 |volume=236 |issue=8 |pages=2292-5 |url=http://www.jbc.org/content/236/8/2292.full.pdf }}</ref>

There may be some 30 active centers per molecule.<ref name=Berry>{{ cite journal |author=Berry WK |title=The turnover number of cholinesterase |journal=Biochem J. |month=Oct |year=1951 |volume=49 |issue=5 |pages=615-20 |url=http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1197565/ }}</ref> AChE is a [[serine hydrolase]] that reacts with acetylcholine at close to the diffusion-controlled rate.<ref name=Bazelyansky>{{ cite journal |author=Bazelyansky M, Robey E, Kirsch JF |title= |journal=Biochem. |month= |year=1986 |volume=25 |issue= |pages=125-30 |url= }}</ref>

==See also==

* [[Catalysis]]

==References==
{{Reflist}}

==External links==

{{DEFAULTSORT:Turnover Number}}
[[Category:Enzyme kinetics]]
[[Category:Chemical kinetics]]
[[Category:Units of catalytic activity]]

{{Science-stub}}

[[de:Wechselzahl]]
[[nl:omzettingsgetal]]
[[ja:ターンオーバー数]]
[[pl:Liczba obrotów]]

Manganite

2010-04-03T05:31:54Z

Su-no-G: +ja

{{Otheruses4|the mineral|the chemical ion MnO42-|Manganate}}
{{Infobox mineral
| name = Manganite
| category = [[Oxide mineral]]
| boxwidth =
| boxbgcolor =
| image = ManganiteUSGOV.jpg
| imagesize =
| alt =
| caption =
| formula = MnO(OH)
| strunz = 04.FD.15
| dana = 06.01.03.01
| symmetry =
| Z =
| molweight =
| color = Dark steel-gray to black, reddish brown in transmitted light, gray-white with brownish tint, with blood-red internal reflections in reflected light
| colour =
| habit = Slender prismatic crystals, massive to fibrous
| system = Monoclinic, 2/m - prismatic, pseudo-orthorhombic
| twinning = Contact and penetration twins on {011}
| cleavage = {010} perfect, {110} and {001} good
| fracture = Uneven
| tenacity = Brittle
| mohs = 4
| luster = Sub-metallic
| streak = Reddish brown to nearly black
| diaphaneity = Opaque, transparent on thin edges
| gravity = 4.29 - 4.34
| density =
| polish =
| opticalprop = Biaxial (+)
| refractive = nα = 2.250(2) nβ = 2.250(2) nγ = 2.530(2)
| birefringence = δ = 0.280, Bireflectance: distinct in grays
| pleochroism = Faint
| 2V = Small
| dispersion = Very strong
| extinction =
| length fast/slow =
| fluorescence=
| absorption =
| melt =
| fusibility =
| diagnostic =
| solubility =
| other =
| alteration =
| references = <ref name=Handbook>http://rruff.geo.arizona.edu/doclib/hom/manganite.pdf Handbook of Mineralogy</ref><ref name=Mindat>http://www.mindat.org/min-2519.html Mindat</ref><ref name=Webmin>http://webmineral.com/data/Manganite.shtml Webmineral data</ref><ref name=Klein>Klein, Cornelis and Cornelius S. Hurbut, Jr., ''Manual of Mineralogy'', Wiley, 20th ed., 1985, p. 317 ISBN 0-471-80580-7</ref>
}}

'''Manganite''' is a [[mineral]]. Its composition is [[manganese]] [[oxide]]-[[hydroxide]], MnO(OH), crystallizing in the [[monoclinic]] system (pseudo-orthorhombic).<ref name=Handbook/> Crystals of manganite are prismatic and deeply striated parallel to their length; they are often grouped together in bundles. The color is dark steel-grey to iron-black, and the [[Lustre (mineralogy)|luster]] brilliant and submetallic. The streak is dark reddish-brown. The [[Mohs hardness|hardness]] is 4, and the [[specific gravity]] is 4.3. There is a perfect cleavage parallel to the brachypinacoid, and less-perfect cleavage parallel to the prism faces. [[Crystal twinning|Twinned crystals]] are not infrequent.

The mineral contains 89.7% [[manganese sesquioxide]]; it dissolves in [[hydrochloric acid]] with evolution of [[chlorine]].

==Occurrence==

Manganite occurs with other manganese oxides in deposits formed by circulating [[meteoric water]] in the weathering environment in [[Clay mineral|clay]] deposits and [[laterite]]s. It forms by low temperature [[hydrothermal]] action in [[Vein (geology)|veins]] in association with calcite, barite, and [[siderite]]. Often associated with [[pyrolusite]], [[braunite]], [[hausmannite]] and [[goethite]].<ref name=Handbook/><ref name=Klein/>

Manganite occurs in specimens exhibiting good crystal form at Ilfeld in the [[Harz Mountains]] of [[Germay]], where the mineral occurs with [[calcite]] and [[barite]] in veins traversing [[porphyry (geology)|porphyry]]. Crystals have also been found at Ilmenau in Thuringia, Neukirch near [[Sélestat]] in [[Alsace]] (newkirkite), Granam near [[Towie]] in Aberdeenshire, and in [[Upton Pyne]] near [[Exeter]], [[UK]] and [[Negaunee, Michigan]], [[United States]]. As an [[ore]] of manganese it is much less abundant than [[pyrolusite]] or [[psilomelane]].

Although described with various other names as early as 1772, the name ''manganite'' was first applied in a publication by W. Haidinger in 1827.<ref>Palache, Charles, Harry Berman and Clifford Frondel, ''The System of Mineralogy'' V. 1, p. 646, Wiley, 7th ed., 1944</ref>
[[Image:Manganite.GIF|thumb|left|Crystal structure of Manganite]]

==References==
{{Reflist}}
*{{1911}}

{{Manganese minerals}}

[[Category:Manganese minerals]]
[[Category:Hydroxide minerals]]
[[Category:Oxide minerals]]

{{oxide-mineral-stub}}

[[ca:Manganita]]
[[cs:Manganit]]
[[es:Manganita]]
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[[fr:Manganite]]
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[[ja:水マンガン鉱]]
[[hu:Manganit]]
[[nl:Manganiet]]
[[pl:Manganit]]
[[ru:Манганит]]
[[sv:Manganit]]
[[uk:Манґаніт]]

Spurrite

2010-04-03T05:30:36Z

Su-no-G: +ja

{{Infobox mineral
| name = Spurrite
| category = Silicate/carbonate mineral
| boxwidth =
| boxbgcolor =
| image = Spurrite Calcium silicate and carbonate Luna county New mexico 1873.jpg
| caption = Spurrite from [[New mexico]]
| formula = Ca5(SiO4)2CO3
| molweight =
| color = Gray, gray white to lilac gray
| habit = Massive to granular
| system = [[monoclinic]] 2/m
| twinning = Polysynthetic twins on [001] and [101]
| cleavage = Distinct on [100]
| fracture = Uneven to splintery
| mohs = 5
| luster = vitreous to resinous
| refractive = nα = 1.640 - 1.641 nβ = 1.674 - 1.676 nγ = 1.679 - 1.681
| opticalprop = Biaxial (-)
| birefringence = δ = 0.039 - 0.040
| pleochroism =
| streak = White
| gravity = 3
| melt =
| fusibility =
| diagnostic =
| solubility =
| diaphaneity = Transparent to translucent
| other = Green cathodoluminescence
| references = <ref name=Handbook>http://rruff.geo.arizona.edu/doclib/hom/spurrite.pdf Mineral Handbook</ref><ref name=Mindat>http://www.mindat.org/min-3734.html Mindat</ref><ref>http://webmineral.com/data/Spurrite.shtml Webmineral data</ref>
}}
'''Spurrite''' is a white, yellow or light blue [[mineral]] with [[monoclinic crystal system|monoclinic]] crystals. Its [[chemical formula]] is [[calcium|Ca]]5([[silicon|Si]][[oxygen|O]]4)2[[carbon|C]]O3.<ref>Richard V. Gaines, H. Catherine W. Skinner, Eugene E. Foord, Brian Mason, and Abraham Rosenzweig: "[[James Dwight Dana|Dana]]'s new mineralogy", p. 1106. John Wiley & Sons, 1997</ref>

Spurrite is generally formed in [[contact metamorphism]] zones as [[mafic|mafic magma]]s are intruded into [[carbonate rock]]s.<ref name="Smith">Smith, J.V. (1960) The Crystal structure of Spurrite, Ca5(SiO4)2CO3. Acta. Cryst. 13, 454</ref> Spurrite's space group is P 2/a. It is biaxial with a birefringence of 0.0390-0.0400, giving second order red interference colors when viewed under crossed [[polarizer]]s in a [[petrographic microscope]].<ref>Barthemy, D. (2000) Afwillite Mineral Data, (http://webmineral.com/data/Afwillite.shtml)</ref>

The [[calcium]] is in six-fold coordination with the [[oxygen]], the [[silicon]] is in a four-fold coordination with the oxygen and the carbon is in two-fold coordination. One unique characteristic of spurrite is that it actually abides by two [[Crystal twinning|twin laws]]. Polysynthetic twinning can occur along its (001) and another type of twinning can occur parallel to its optical axes.<ref name="Smith"/>

==Discovery and occurrence==
Spurrite was first described in 1908 for an occurrence in the Terneras Mine, [[Velardeña]] District, [[Durango]], [[Mexico]]. It was named for American economic geologist, Josiah Edward Spurr (1870-1950).<ref name=Mindat/>

In addition to its type locality, spurrite has been reported from [[Riverside County, California]]; [[Luna County, New Mexico]]; and from the [[Little Belt Mountains]], [[Lewis and Clark County, Montana]]. It is also found in Ireland, Scotland, New Zealand, Turkey, Israel, Japan and Siberia.<ref name=Handbook/>

==Cement manufacture contaminant==
Spurrite forms as contaminating ''spurrite rings'' on the walls of cement kilns during the production of [[Portland cement]].<ref>Mosci, Ricardo, 1998, ''How To Eliminate Calcining Zone Rings'', Cement America http://cementamericas.com/mag/cement_eliminate_calcining_zone/ </ref>

==References==
<references/>

[[Category:Silicate minerals]]
[[Category:Carbonate minerals]]
{{silicate-mineral-stub}}

[[it:Spurrite]]
[[ja:スパー石]]
[[nl:Spurriet]]

Potassium hydride

2010-03-19T12:24:54Z

Su-no-G: +ja

{{chembox
| verifiedrevid = 303383649
| ImageFile = NaCl polyhedra.png
| IUPACName =
| OtherNames =
| Section1 = {{Chembox Identifiers
| Abbreviations =
| CASNo = 7693-26-7
| CASNo_Ref = {{cascite}}
| PubChem = 82127
| EINECS = 232-151-5
| InChI =
| RTECS =
}}
| Section2 = {{Chembox Properties
| Formula = KH
| MolarMass = 40.1062 g/mol
| Appearance = colourless crystals
| Density = 1.47 g/cm3
| MeltingPt =
| BoilingPt = 316 °C
| Solubility =
| SolubleOther =
| pKa =
}}
| Section3 = {{Chembox Structure
| CrystalStruct = [[cubic]], [[Pearson symbol|cF8]]
| SpaceGroup = Fm3m, No. 225
}}
| Section7 = {{Chembox Hazards
| EUClass =
| EUIndex =
| NFPA-H =
| NFPA-F =
| NFPA-R =
| NFPA-O =
| RPhrases =
| SPhrases =
| FlashPt =
| PEL =
| LD50 =
}}
| Section8 = {{Chembox Related
| OtherCations = [[Lithium hydride]] [[Sodium hydride]] [[Rubidium hydride]] [[Caesium hydride]]
}}
}}

'''Potassium hydride''', KH, is a [[chemical compound]] of [[potassium]] and [[hydrogen]]. It is a [[hydride]] of potassium. It reacts with water according to the reaction:

:KH + H2O → KOH + H2

The reaction is so vigorous that often the hydrogen gas produced will, due to the heat of the reaction, ignite with the oxygen in the air, producing a lilac flame from the presence of potassium ions in the hydrogen fire. Potassium hydride is also [[pyrophoric]], and requires careful handling. For this reason it is sold commercially as a slurry in [[mineral oil]]. In one study the compound is dispersed in [[paraffin]] to allow for better dispensing <ref>''Potassium Hydride in Paraffin: A Useful Base for Organic Synthesis'' Douglass F. Taber and Christopher G. Nelson [[J. Org. Chem.]]; '''2006'''; 71(23) pp 8973 - 8974; (Note) {{DOI|10.1021/jo061420v}}</ref>

Potassium hydride can be formed by direct combination of the metal and hydrogen. This reaction was discovered by [[Humphry Davy]] soon after his 1807 discovery of potassium, when he noted that the metal would vaporize in a current of hydrogen when heated just below its boiling point.<ref name=davy>
Humphry Davy (1808), ''The Bakerian Lecture on some new phenomena of chemical changes produced by electricity, particularly the decomposition of fixed alkalies, and the exhibition of the new substances which constitute their bases; and on the general nature of alkaline bodies.'' Philosophical Transactions of the Royal Society, volume 88, pages 1–44. In ''The Development of Chemistry, 1789-1914: Selected essays'', edited by D. Knight, pages 17–47.
</ref>{{rp|p.25}}

Potassium hydride is a powerful [[base (chemistry)|base]] (more reactive than [[sodium hydride]]), which can be used to [[deprotonation|deprotonate]] organic molecules. Potassium hydride is also very thermally conductive {{Fact|date=December 2008}}.

==See also==
* [[Sodium hydride]]

==References==
<div class="references-small"><references/></div>

{{Potassium compounds}}

[[Category:Metal hydrides]]
[[Category:Potassium compounds]]
[[Category:Bases]]

[[de:Kaliumhydrid]]
[[es:Hidruro de potasio]]
[[fr:Hydrure de potassium]]
[[ja:水素化カリウム]]
[[nl:Kaliumhydride]]
[[fi:Kaliumhydridi]]
[[zh:氢化钾]]

Lithium–air battery

2010-03-19T06:03:04Z

Su-no-G: +ja

A '''lithium-air battery''' is a [[battery (electricity)|battery]] in which a [[lithium]] [[anode]] is electrochemically coupled to atmospheric [[oxygen]] through an air [[cathode]]. During discharge, lithium [[cation]]s flow from the anode through an [[electrolyte]] and combine with oxygen at the cathode (typically consisting of porous [[carbon]]) to form [[lithium oxide]] Li2O or [[lithium peroxide]] Li2O2 which is inserted in the cathode; this is coupled to the flow of electrons from the battery's anode to the cathode through a load circuit.

Lithium air batteries have higher [[energy density]] than [[lithium ion battery|lithium ion batteries]] because of the lighter cathode and the fact that oxygen is freely available in the environment and does not need to be stored in the battery.<ref>{{citation|url=http://www.sciencedaily.com/releases/2009/05/090517152557.htm|date=2009-05-18|title=Air-Fueled Battery Could Last Up To 10 Times Longer: Ground-Breaking Technology For Electric Cars|work=ScienceDaily}}</ref>
Theoretically, with oxygen as an unlimited cathode reactant, the capacity of the battery is limited by the Li anode. Lithium air batteries are currently under development and are not yet commercially available.<ref>{{citation|url=http://www.sciencedaily.com/releases/2009/12/091230024401.htm|title=Lithium-Air Batteries Could Displace Gasoline in Future Cars|date=2009-12-31|work=ScienceDaily}}</ref>

==History==
In the mid-1990s, Abraham and co-workers demonstrated the first practical non-aqueous Li-air battery with the use of a Li negative electrode (cathode), a porous [[carbon]] positive electrode (anode), and a [[gel]] [[polymer]] [[electrolyte]] [[membrane]] that served as both the separator and ion-transporting medium.<ref name="refname1"/><ref name="refname2"/> Oxygen from the atmosphere enters the pores of the carbon cathode to serve as the cathode active material. In the discharge of the Li-air battery, this oxygen is reduced and the products are stored in the pores of the carbon electrode. As a result, the cell capacity is expressed as [[ampere-hour]] per gram of the carbon in the cathode. The Li ion conducting gel polymer electrolytes used to construct polymer Li-air cells included those based on [[polyacrylonitrile]] (PAN)<ref name="refname3"/> and [[polyvinylidene fluoride]] (PVdF)<ref name="refname4"/>. The electrolyte can also be organic liquid, dry organic polymer or inorganic solid electrolytes.

Engineers at the [[University of Dayton Research Institute]] are credited for developing the world's first solid-state, [[Rechargeable battery|rechargeable]] lithium air battery, designed to address the [[fire]] and [[explosion]] risk of other lithium rechargeable batteries and make way for development of large-size lithium rechargeables for a number of industry applications, including [[Hybrid electric vehicle|hybrid]] and [[electric cars]].<ref>{{cite news |url=http://news.udayton.edu/News_Article/?contentId=25610 |title=A Research First |work=University of Dayton News |date=2009-11-17 |accessdate=2009-11-23}}</ref>

== Properties of metal-air batteries ==

Of the various metal-air battery chemical couples (Table 1), the Li-air [[Battery (electricity)|battery]] is the most attractive since the cell discharge reaction between Li and oxygen to yield [[Lithium oxide|Li2O]], according to 4Li + O2 → 2Li2O, has an [[open-circuit voltage]] of 2.91 V and a theoretical [[specific energy]] of 5200 Wh/kg. In practice, oxygen is not stored in the battery, and the theoretical specific energy excluding oxygen is 11140 Wh/kg.

{| class="wikitable"
|-
! Metal/air battery
! Calculated OCV, V
! Theoretical specific energy, Wh/kg (including oxygen)
! Theoretical specific energy, Wh/kg (excluding oxygen)
|-
| Li/O2
| 2.91
| 5200
| 11140
|-
| Na/O2
| 1.94
| 1677
| 2260
|-
| Ca/O2
| 3.12
| 2990
| 4180
|-
| Mg/O2
| 2.93
| 2789
| 6462
|-
| Zn/O2
| 1.65
| 1090
| 1350
|}
The possible discharge cell reactions and the associated cell voltages in agreement with the experimental discharge data from the test cell are:

2Li + O2 → Li2O2; Go = -145 Kcal (Eo = 3.1 V) [1] 
4Li + O2 → 2Li2O; Go = -268 Kcal (Eo = 2.91 V) [2] 

Indeed, Abraham et al showed using [[Raman spectroscopy|Raman spectroscopic analysis]] of the products that the main discharge reaction is the [[Redox|reduction]] of oxygen to form Li2O2<ref name="refname1"/>.

Abraham and Jiang also demonstrated that the Li/oxygen battery is rechargeable when the carbon cathode contains [[catalyst]]s derived from [[Complex (chemistry)|complexes]] or [[oxide]]s of metals such as [[cobalt]]<ref name="refname1"/>. The catalyst can be viewed as lowering the [[overvoltage]] for the [[Redox|oxidation]] of Li2O2 or Li2O to form metallic Li and oxygen.

The non-aqueous metal-air batteries represent a class of potentially ultrahigh [[energy density]] power sources useful for a variety of civilian applications. When fully developed these batteries are expected to exhibit practical specific energies of over 1000 [[Watt-hour|Wh]]/[[Kilogram|kg]]<ref>{{cite journal |url=http://scitation.aip.org/getabs/servlet/GetabsServlet?prog=normal&id=JESOAN000157000001000A50000001&idtype=cvips&gifs=yes |title=A Solid-State, Rechargeable, Long Cycle Life Lithium–Air Battery |first=Binod |last=Kumar |coauthors=Jitendra Kumar; Robert Leese; Joseph P. Fellner; Stanley J. Rodrigues; K. M. Abraham |journal=Journal of the Electrochemical Society |volume=157 |number=1 |pages=A50-A54 |year=2010}}</ref> (3.6 [[Joule|MJ]]/kg).

Abraham and co-workers also showed that a magnesium/oxygen battery can be constructed with a Mg ion [[Conductive polymer|conducting polymer]] electrolyte of the composition, 30PVdF-HFP-62.5 EC/PC-7.5Mg(ClO4)2, with a [[Electrical conductivity|conductivity]] of 1.2x10-3 S/cm at {{convert|20|C|F}}. This Mg/O2 cell showed an open circuit potential of about 1.2 V at [[room temperature]], lower than the calculated value of 2.93 V, and its discharge voltage ranged between 0.7 to 1.1 V depending on the [[current density]], carbon cathode and electrolyte composition<ref name="refname5"/>.

== References ==
{{Reflist|
refs=
<ref name="refname1">{{cite journal |url=http://dx.doi.org/10.1149/1.1836378 |first=K. M. |last=Abraham |coauthors=Z. Jiang |title=A Polymer Electrolyte-Based Rechargeable Lithium/Oxygen Battery |journal=Journal of the Electrochemical Society |volume=143 |number=1 |pages=1-5 |year=1996}}</ref>
<ref name="refname2">K. M. Abraham and Z. Jiang, [[United States patent law|US Patent]] 5,510,209 (1996)</ref>
<ref name="refname3">{{cite journal |url=http://dx.doi.org/10.1016/S0013-4686(97)10168-2 |first=K. M. |last=Abraham |coauthors=H.S. Choe; D.M. Pasquariello |title=Polyacrylonitrile electrolyte-based Li ion batteries |journal=Electrochimica Acta
|volume=43 |number=16-17 |year=1998 |pages=2399-2412}}</ref>
<ref name="refname4">{{cite journal |url=http://pubs.acs.org/doi/abs/10.1021/cm970075a |first=K. M. |last=Abraham |coauthors=Z. Jiang; B. Carroll |title=Highly Conductive PEO-like Polymer Electrolytes |journal=Chemistry Of Materials |volume=9 |issue=9 |pages=1978-1988 |year=1997}}</ref>
<ref name="refname5">{{cite journal |url=http://www.e-kemsciences.com/Brief_HistoryLithium_Air_Batteries.pdf |title=A Brief History of Non-aqueous Metal-Air Batteries |first=K. M. |last=Abraham |journal=ECS Transactions |publisher=The Electrochemical Society |volume=3 |issue=42 |pages=67-71 |year=2008}}</ref>
}}
{{Refbegin}}
* A. Dobley, C. Morein, R. Roark, and K. M. Abraham, 42nd Power Sources Conference, [[Philadelphia, Pennsylvania|Philadelphia, PA]], June 2006
* [http://www.e-kemsciences.com/KMA.htm K.M. Abraham Ph.D. at E-KEM Sciences]
{{Refend}}

==See also==
* [[Lithium battery]]
* [[Lithium ion battery]]
* [[Lithium iron phosphate battery]]
* [[Lithium polymer battery]]
* [[Nanowire battery]]
* [[Power-to-weight ratio]]

==External links==
* [http://www.anl.gov/Media_Center/News/2009/batteries090915.html Argonne opens chapter in battery research -- lithium air]
* [http://www.anl.gov/Media_Center/News/2009/news091218.html Argonne advanced battery research driving to displace gasoline]

{{GalvanicCells}}

{{DEFAULTSORT:Lithium Air Battery}}
[[Category:Lithium-ion batteries]]
[[Category:Metal-air fuel cell/batteries]]
[[ja:リチウム・空気電池]]

Nucleophilic acyl substitution

2010-03-13T12:29:39Z

Su-no-G: + ja

'''Nucleophilic acyl substitution''' describes the [[substitution reaction]] involving [[nucleophile]]s and [[acyl]] compounds. Acyl compounds are [[carboxylic acid]] derivatives including [[ester]]s, [[amide]]s and [[acid halide]]s. Nucleophiles include anionic reagents such as [[alkoxide]] compounds and [[enolate]]s or species of high basicity, such as [[amine]]s <ref>{{cite book | title = Organic Chemistry | author = John McMurry | edition = 2nd Ed. | isbn = 0-534-07968-7}}</ref>.

== Reaction mechanism==
[[Image:AcylSubstitution.svg|right|frame|Nucleophilic acyl substitution with [[nucleophile]] (Nu) and [[leaving group]] (L)]]The reaction of a [[nucleophile]] with a [[Polar molecule|polar]] [[carbonyl]] group such as a [[ketone]] or an [[aldehyde]] results in [[nucleophilic addition]] with a [[Tetrahedral molecular geometry|tetrahedral]] [[alkoxy|alkoxide]] as primary reaction product. However, in [[acyl]] compounds the carbonyl group is bonded to a [[substituent]] that can act as a [[leaving group]]. Upon attack of the nucleophile at the carbonyl group, as before, a tetrahedral intermediate is formed with the nucleophile, the leaving group and the oxygen anion attached to the central carbon atom. The [[alkoxy]] group can now revert back to the [[carbonyl]] group and at the same time expel the [[leaving group]]. The nucleophile has taken the position previously occupied by the leaving group.

This mechanism is supported by [[isotope labeling]] experiments. The 18O labeled ethoxy oxygen atom in [[ethyl propionate]] (leaving group = EtO) winds up exclusively in the ethanol product in a reaction with NaOH <ref>Attributed to D.N. Kursanov (1899) McMurry</ref>.

Acyl substitution is basically a two-step [[nucleophilic addition]] and [[elimination reaction]]. Both reaction steps are [[reversible reaction]]s. The relative strength of both nucleophilic species determines the reaction outcome, but in practical reactions the leaving group is by far the poorest nucleophile.

Carboxylic acids as well as the related esters and amides are often insufficiently reactive to undergo nucleophilic substitution. The carboxylic acid is often activated by conversion to the acyl chloride using [[thionyl chloride]].

== Reactions ==
Many [[condensation reaction]]s are nucleophilic acyl substitutions. [[Carboxylic acid]]s react with chlorine donors such as [[thionyl chloride]] or [[phosphorus trichloride]] to [[acid halide|acid chlorides]], with [[alcohol]]s to [[ester]]s in [[esterfication]] and carboxylic acids [[self-condensation|selfcondense]] to [[acid anhydride]]s. With [[amine]]s they form [[amide]]s. Esters react with [[Grignard reagent]]s in a nucleophilic acyl substitution followed by a [[nucleophilic addition]] to tertiary [[alcohols]]. Esters also react with [[Enolate]] nucleophiles. For example [[ethyl acetate]] reacts with [[acetone]] to [[acetylacetone]].

The [[Baker-Venkataraman rearrangement]] is a nucleophilic acyl substitution used in the synthesis of [[flavone]]s. In the [[Weinreb ketone synthesis]] ketones are synthesized from [[carboxylic acid]] precursors. An unusual intramolecular acyl substitution is the [[Chan rearrangement]].

== See also==
* The [[substitution reaction]]s in [[organic chemistry]] are '''nucleophilic acyl substitution''', [[nucleophilic aliphatic substitution]] and [[nucleophilic aromatic substitution]].

== External links ==
* Reaction of [[ethyl acetate]] with [[acetone]] in [[Organic Syntheses]] Coll. Vol. 3, p.16; Vol. 20, p.6 [http://www.orgsyn.org/orgsyn/prep.asp?prep=cv3p0016 Article]

== References ==
{{Reflist}}

[[Category:Substitution reactions]]
[[Category:Reaction mechanisms]]

[[es:Sustitución nucleófila acílica]]
[[ja:求核アシル置換反応]]
[[pt:Substituição nucleofílica acílica]]
[[zh:亲核酰基取代反应]]

Takuzo Aida

2010-03-13T11:06:53Z

Su-no-G: + ja

{{orphan|date=October 2009}}

'''Tazuko Aida''' (born 1956 in Japan) is an award-winning [[Polymer chemistry|polymer chemist]]. He has maintained a research laboratory at the [[University of Tokyo]] for over 20 years.

==Personal life==
Aida maintains that he chose [[chemistry]] as his field of study because it offered less competition to obtain admission to Japanese colleges at the time than other scientific disciplines (he describes himself as "lazy"). As a graduate student, his main extracurricular activity was [[mountain climbing]].

==Achievements and honors==
Aida has published 210 [[Academic publishing|research papers]] and holds 66 [[patent]]s (December 2008). His achievements include light-harvesting [[dendrimer]]s, such as the first dendritic macromolecule to encapsulate a dye unit, and cancer-therapy molecules. His group worked for over two years to develop a [[catalysis|catalytic]] procedure for polymerizing [[ethylene]]. Their procedure is accomplished in one continuous reaction. His group performed the first successful formation of conductive self-assembled [[Carbon nanotube|graphite nanotubes]]. He has constructed a molecular-scale snipping apparatus, used to hold molecules and modify their chemical arrangement.

In 2009 Aida received the [[American Chemical Society]]'s award in Polymer Chemistry.

==References==
[[Chemical & Engineering News]], 19 January 2009, "2009 ACS National Award Winners", p. 72

[[Category:Japanese scientists]]
[[Category:University of Tokyo]]
[[ja:相田卓三]]

Radical initiator

2010-03-12T13:02:38Z

Su-no-G: + ja

{{Unreferenced|date=December 2009}}
In [[chemistry]], '''radical initiators''' are substances that can produce [[radical (chemistry)|radical species]] under mild conditions and promote [[radical polymerization]] reactions. These substances generally possess weak bonds—bonds that have small [[bond dissociation energy|bond dissociation energies]]. Radical initiators are utilized in industrial processes such as [[polymer]] synthesis. Typical examples are [[halogen]] [[molecule]]s, [[azo compound]]s, and [[organic peroxide]]s.

*Like all [[diatomic]] [[molecule]]s, [[halogen]]s can generate two free radicals resulting from the [[homolysis]] of the bond, but [[halogen]]s undergo the [[homolysis|homolytic fission]] relatively easily. [[Chlorine]], for example, gives two chlorine radicals (Cl•) by irradiation with [[ultraviolet|ultraviolet light]]. This process is used for [[alkane#halogenation reaction|chlorination]] of [[alkane]]s.

*[[Azo compound]]s (R-[[nitrogen|N]]=[[nitrogen|N]]-R') can be the precursor of two [[carbon]]-centered radicals (R• and R'•) and [[nitrogen]] gas upon heating and/or by irradiation. For example, [[Azobisisobutyronitrile|AIBN]] and [[ABCN]] yield isobutyronitrile and cyclohexanecarbonitrile radicals, respectively.
:[[Image:AIBN-radical-2D.png|400px|AIBN initiator]]

*[[Organic peroxide]]s each have a peroxide bond (-[[oxygen|O]]-[[oxygen|O]]-), which is readily cleaved to give two [[oxygen]]-centered radicals. The oxyl radicals are rather unstable and believed to be transformed into relatively stable [[carbon]]-centered radicals. For example, di-''t''(tertiary)-[[butyl]]<nowiki>peroxide</nowiki> (''t''[[butyl|Bu]][[oxygen|OO]]''t''[[butyl|Bu]]) gives two ''t''-butanoyl radicals (''t''[[butyl|Bu]][[oxygen|O]]•) and the radicals become [[methyl]] radicals ([[carbon|C]][[hydrogen|H]]3•) with the loss of [[acetone]]. [[Benzoyl peroxide]] (([[phenyl|Ph]][[carbon|C]][[oxygen|OO]])2) generates benzoyloxyl radicals ([[phenyl|Ph]][[carbon|C]][[oxygen|OO]]•), each of which loses [[carbon dioxide]] to be converted into a [[phenyl]] radical ([[phenyl|Ph]]•). [[Methyl ethyl ketone peroxide]] is also common, and [[acetone peroxide]] is on rare occasions used as a radical initiator, too.

Radical initiators, especially [[azo compound]]s and [[organic peroxide]]s, are inherently unstable. They must be kept in a cool place or refrigerated. Care should be taken with the handling of the compounds or an [[explosion]] may occur.

See also: [[Initiator]]

{{DEFAULTSORT:Radical Initiator}}
[[Category:Polymer chemistry]]

[[de:Radikalstarter]]
[[ja:ラジカル開始剤]]

Sodium cyanoborohydride

2010-03-12T11:52:10Z

Su-no-G: + ja

{{chembox
| verifiedrevid = 268898749
| Name = Sodium cyanoborohydride
| ImageFile = Sodium-cyanoborohydride-2D.png

| ImageName = Sodium cyanoborohydride
| OtherNames = Sodium cyanotrihydridoborate
| Section1 = {{Chembox Identifiers
| CASNo = 25895-60-7
| CASNo_Ref = {{cascite}}
| EINECS = 247-317-2
| PubChem = 24849595
}}
| Section2 = {{Chembox Properties
| Formula = NaBH3CN
| MolarMass = 62.84 g/mol
| Appearance = white to off-white powder, [[hygroscopic]]
| Density = 1.20 g/cm3
| Solubility = soluble
| MeltingPt = 241 °C decomp.
}}
| Section7 = {{Chembox Hazards
| ExternalMSDS = [http://msds.chem.ox.ac.uk/SO/sodium_cyanoborohydride.html External MSDS]
| EUIndex = not listed
| NFPA-H = 3
| NFPA-R = 2
| NFPA-F = 2
| NFPA-O = W
}}
| Section8 = {{Chembox Related
| OtherAnions = [[Sodium borohydride]]
| OtherCations =
| OtherCpds = [[Lithium aluminium hydride]]
}}
}}
'''Sodium cyanoborohydride''' is the [[inorganic compound]] with the formula [[Sodium|Na]][[Boron|B]][[Hydrogen|H3]]([[Carbon|C]][[Nitrogen|N]]). This colourless salt is widely used in [[organic synthesis]] for the reduction of [[imine]]s.

==Preparation and use==
The reagent may be prepared, either by treating [[sodium cyanide]] with [[borane]], or by reacting sodium borohydride with [[mercuric cyanide]]. Owing to the presence of the electron-withdrawing [[cyanide]] substituent, [B(CN)H3]− is far less nucleophilic than is [BH4]−, as found in [[sodium borohydride]].<ref>Ellen W. Baxter, Allen B. Reitz Reductive Aminations of Carbonyl Compounds with Borohydride and Borane Reducing Agents in Organic Reactions, 2002, John Wiley and Sons. {{DOI|10.1002/0471264180.or059.01}}</ref>

Sodium cyanoborohydride is a mild reducing agent that converts [[imine]]s to [[amine]]s. It can be used to exchange the oxygen for an amine group on the carbonyl carbon of aldehydes or ketones when reacted with ammonia or a primary amine. Selectivity is achieved at mildly basic solutions ([[pH]] 7-10). Owing to this selectively, the reagent is ideal for [[reductive amination]]s. This reduction is known sometimes as the Borch Reaction.<ref>{{Cite journal | author = Richard F. Borch and Mark D. Bernstein and H. Dupont Durst | title = Cyanohydridoborate Anion as a Selective Reducing Agent | journal = [[J. Am. Chem. Soc.]] | pages = 2897–2904 | volume = 93 | issue = 12 | year = 1971 | doi = 10.1021/ja00741a013}}</ref> The salt is mildly water-sensitive, but tolerates aqueous conditions.<ref>{{cite journal | author = Timothy M. Beard and Nicholas J. Turner | title = Deracemisation and Stereoinversion of alpha-Amino Acids Using D-Amino Acid Oxidase and Hydride Reducing Agents | journal = [[Chemical Communications]] | pages = 246–7 | issue = 3 | year = 2002}}</ref> In addition, sodium cyanoborohydride is often used in [[hydrogenolysis]] reactions, such as the opening of [[acetals]].

==References==
{{reflist}}

[[Category:Boron compounds]]
[[Category:Sodium compounds]]

{{inorganic-compound-stub}}
{{Sodium compounds}}

[[ar:سيان بورهيدريد الصوديوم]]
[[de:Natriumcyanoborhydrid]]
[[es:Cianoborohidruro de sodio]]
[[fr:Cyanoborohydrure de sodium]]
[[ja:シアノ水素化ホウ素ナトリウム]]
[[nl:Natriumcyanoboorhydride]]
[[zh:氰基硼氢化钠]]

Phenylsilane

2010-03-11T18:39:38Z

Su-no-G: +ja

{{chembox
| Name = Phenylsilane
| ImageFileL1 = Phenylsilane.png
| ImageSizeL1 = 80 px
| ImageNameL1 = skeletal formula of phenylsilane
| ImageFileR1 = Phenylsilane-3D-vdW.png
| ImageSizeR1 = 120 px
| ImageNameR1 = ball-and-stick model of the phenylsilane molecule
| OtherNames = Silylbenzene
| Section1 = {{Chembox Identifiers
| CASNo = 694-53-1
}}
| Section2 = {{Chembox Properties
| Formula = C6H8Si
| MolarMass = 108.22 g/mol
| Appearance = Colorless liquid
| Density = 0.878 g/cm³
| Solubility in water = N/A (very reactive with water)
| MeltingPt = N/A
| BoilingPt = 119-121 °C (433-394 K)
}}
| Section3 = {{Chembox Hazards
| MSDS = [http://www.sigmaaldrich.com/cgi-bin/hsrun/Suite7/Suite/HAHTpage/Suite.HsSigmaAdvancedSearch.formAction]
| RPhrases = 11-14/15-20/22-36/37/38
| SPhrases = 16-43
}}
}}

'''Phenylsilane''', also known as '''silylbenzene''', a colorless liquid, is one of the simplest [[organosilicon|organosilane]]s with the formula [[Carbon|C]]6[[Hydrogen|H]]5[[Silicon|Si]]H3. It is structurally related to [[toluene]], with a silyl group replacing the [[methyl]] group. Both of these compounds have similar densities and boiling points due to these similarities. Phenylsilane is soluble in organic solvents.

==Synthesis and reactions==
Phenylsilane is produced in two steps from Si(OEt)4. In the first step magnesium bromobenzene is added to form Ph-Si(OEt)3. The approach of using a magnesium-bromine reagent is called a [[Grignard reaction]]. Reduction of the resulting Ph-Si(OEt)3 product with LiAlH4 affords phenylsilane<ref>Minge, O.; Mitzel, N. W.; and Schmidbaur, H. Synthetic Pathways to Hydrogen-Rich Polysilylated Arenes from Trialkoxysilanes and Other Precursors. Organometallics 2002, 21, 680-684. {{doi|10.1021/om0108595}}</ref>.

Ph-MgBr + Si(OEt)4 → Ph-Si(OEt)3 + MgBr(OEt)

4 Ph-Si(OEt)3 + 3 LiAlH4 → 4 Ph-SiH3 + 3 LiAl(OEt)4
==Uses==
Phenylsilane can be used to reduce tertiary [[phosphine oxide]]s to the corresponding tertiary [[phosphine]].

P(CH3)3O + PhSiH3 --> P(CH3)3 + PhSiH2OH

The use of phenylsilane proceeds with [[retention of configuration]] at the phosphine. For example, cyclic chiral tertiary phosphine oxides can be reduced to cyclic tertiary phosphines<ref>Weber, W. P. ''Silicon Reagents for Organic Synthesis''. Springer-Verlag: Berlin, 1983. ISBN 0387116753.</ref>.

Phenylsilane can also be combined with [[cesium fluoride]]. In [[aprotic solvent]]s, it becomes a nonnucleophilic hydride donor. Specifically, phenylsilane-caesium fluoride has been shown to reduce 4-oxazolium salts to 4-oxazolines. This reduction gives yields of 95%<ref>Fleck, T. J. ''Encyclopedia of Reagents for Organic Synthesis'' {{doi|10.1002/047084289X.rp101}}</ref>.

==References==
{{reflist}}

[[Category:Organosilicon compounds]]
[[ja:フェニルシラン]]

Propyl group

2010-03-10T14:38:32Z

Su-no-G: +ja

{{Unreferenced|date=December 2009}}
In [[organic chemistry]], '''propyl''' is a three-[[carbon]] [[alkyl]] [[substituent]] with [[chemical formula]] '''-[[Carbon|C]]3[[Hydrogen|H]]7'''. It is the substituent form of the [[alkane]] [[propane]].

For example:

[[Image:Propyl ethanoate.png|thumb|center|Propyl ethanoate, also called propyl [[acetate]].]]

This is '''[[propyl ethanoate]]''', an [[ester]]. The propyl group is attached to the molecule after the middle oxygen.

There are two [[isomer]]ic forms of propyl:
* with the substituent attached to one of the end carbons (called prop-1-yl in the [[IUPAC nomenclature]], or '''n-propyl''' (Pr-n) in the old naming system); and
* with the substituent attached to the middle carbon (called methylethyl in the IUPAC system, or [[isopropyl]] in the old system).

In addition there is a third, cyclic, form called cyclopropyl, or '''c-propyl'''. It is not isomeric with the other two forms, having the chemical formula '''-[[Carbon|C]]3[[Hydrogen|H]]5'''.

[[Image:Propyl groups.png|thumb|600px|right|From left to right: the two isomeric groups prop-1-yl and prop-2-yl, and the non-isomeric cyclopropyl group.]]

==Examples==
* [[isopropyl alcohol]]

==See also==
* [[methyl]]
* [[Ethyl group|ethyl]]
* [[butyl]]
* [[pentyl]] / [[amyl]]

[[Category:Functional groups]]

[[de:Propylgruppe]]
[[fr:Propyle]]
[[it:Propile]]
[[ja:プロピル基]]
[[nl:Propylgroep]]
[[pl:Grupa propylowa]]
[[pt:Propil]]
[[ru:Пропил]]
[[sv:Propylgrupp]]
[[zh:丙基]]

Trichlorosilane

2010-03-09T16:21:12Z

Su-no-G: +ja

{{chembox
| Watchedfields = changed
| verifiedrevid = 261965768
| ImageFile = Trichlorosilane-2D-stereo.png
| ImageSize = 120px
| ImageFileL1 = Trichlorosilane-3D-balls.png
| ImageSizeL1 = 120px
| ImageFileR1 = Trichlorosilane-3D-vdW.png
| ImageSizeR1 = 120px
| IUPACName = trichlorosilane
| OtherNames = silyl trichloride, silicochloroform
| Section1 = {{Chembox Identifiers
| CASNo = 10025-78-2
| CASNo_Ref = {{cascite}}
| PubChem =
| SMILES = [H][Si](Cl)(Cl)Cl
| EINECS = 233-042-5
| RTECS = VV5950000
| UNNumber = 1295
}}
| Section2 = {{Chembox Properties
| Formula = HCl3Si
| MolarMass = {{val|135.45|u=g/mol}}
| Appearance = colourless liquid
| Density = {{val|1.342|e=3|ul=kg/m3}}
| MeltingPt = {{val|-126.6|ul=°C}}
| BoilingPt = {{val|31.8|u=°C}}
| Solubility = [[hydrolysis]]
}}
| Section3 = {{Chembox Hazards
| ExternalMSDS = [http://www.ilo.org/public/english/protection/safework/cis/products/icsc/dtasht/_icsc05/icsc0591.htm ICSC 0591]
| EUClass = Highly flammable ('''F+''') Harmful ('''Xn''') Corrosive ('''C''')
| EUIndex = 014-001-00-9
| NFPA-H = 3
| NFPA-F = 4
| NFPA-R = 2
| NFPA-O = W
| RPhrases = {{R12}}, {{R14}}, {{R17}}, {{R20/22}}, {{R29}}, {{R35}}
| SPhrases = {{S2}}, {{S7/9}}, {{S16}}, {{S26}}, {{S36/37/39}}, {{S43}}, {{S45}}
| FlashPt = {{val|-27|u=°C}}
| Autoignition = {{val|185|u=°C}}
| ExploLimits = 1.2–90.5%
| PEL =
}}
| Section8 = {{Chembox Related
| OtherFunctn = [[Chlorosilane]] [[Dichlorosilane]] [[Silicon tetrachloride]]
| Function = chlorosilanes
| OtherCpds = [[Trifluorosilane]] [[Tribromosilane]] [[Chloroform]]
}}
}}

'''Trichlorosilane''' is a [[chemical compound]] containing [[silicon]], [[hydrogen]], and [[chlorine]]. At high temperatures, it decomposes to produce silicon, and therefore purified trichlorosilane is the principal source of ultrapure silicon in the [[semiconductor]] industry. In water, it rapidly decomposes to produce a [[silicone]] polymer while giving off [[hydrochloric acid]]. Because of its reactivity and wide availability, it is frequently used in the synthesis of silicon-containing [[organic chemistry|organic]] compounds.

== Production ==
Industrially, trichlorosilane is produced by blowing [[hydrogen chloride]] through a bed of silicon powder at 300°C. There, they combine to make trichlorosilane and hydrogen according to the [[chemical equation]]

:Si + 3 HCl → HSiCl3 + H2

A properly designed reactor can achieve a yield of 80-90% trichlorosilane. The major byproducts are [[silicon tetrachloride]] ([[chemical formula]] SiCl4), hexachlorodisilane (Si2Cl6), and [[dichlorosilane]] (H2SiCl2), from which trichlorosilane can be separated by [[distillation]].

The reverse process is used in the production of silicon of higher purity.

== Application ==
Trichlorosilane is the basic ingredient used in the production of purified [[polysilicon]]s.

==References==

* [http://www.osha.gov/SLTC/semiconductors/substratemfg/polysiliconprod.html Semiconductors: Silicon: Substrate Manufacture: Polycrystalline Silicon Production]

==External links==
*[http://www.polysilicon.in Polysilicon Plant in India].

[[Category:Silicon compounds]]

[[de:Trichlorsilan]]
[[ja:トリクロロシラン]]
[[nl:Trichloorsilaan]]
[[ru:Трихлорсилан]]
[[zh:三氯氢硅]]

Benzeneselenol

2010-03-06T12:00:55Z

Su-no-G: +ja

{{chembox
| Name = Benzeneselenol
| ImageFileL1 = Benzeneselenol-2D-skeletal.png
| ImageSizeL1 = 100 px
| ImageFileR1 = Benzeneselenol-3D-vdW.png
| ImageSizeR1 = 125 px
| IUPACName = benzeneselenol
| OtherNames = Selenaphenol, selenophenol, phenylselenol
| Section1 = {{Chembox Identifiers
| SMILES = c1ccccc1Se
| CASNo = 645-96-5
| RTECS =
}}
| Section2 = {{Chembox Properties
| Formula = C6H6Se
| MolarMass = 157.07 g/mol
| Appearance = colourless liquid
| Density = 1.479 g/cm3
| Solubility = slightly
| Solvent = other solvents
| SolubleOther = most organic solvents
| MeltingPt =
| BoilingPt = 71-72 °C (18 mm Hg)
| Viscosity =
| RefractIndex = 1.616
}}
| Section3 = {{Chembox Structure
| Coordination =
| CrystalStruct =
| Dipole = 1.1 [[Debye|D]]
}}
| Section7 = {{Chembox Hazards
| ExternalMSDS =
| MainHazards = toxic
| FlashPt =
| RPhrases = 23/25-33-50/53
| SPhrases = 20/21-28-45-60-61
}}
| Section8 = {{Chembox Related
| OtherCpds = [[Thiophenol|C6H5SH]], [[Hydrogen selenide|H2Se]], [[diphenyl diselenide]]
}}
}}

'''Benzeneselenol''' is the [[chemical compound]] with the formula C6H5SeH, often abbreviated [[phenyl|Ph]]SeH. This intensely malodorous liquid is a useful reagent in [[organic synthesis]].

==Synthesis and basic properties==
PhSeH is prepared via a [[Grignard reagent]]:<ref>{{OrgSynth | author = Foster, D. G. | title = Selenophenol | collvol = 3 | collvolpages = 771 | year = 1955 | prep = cv3p0771}}</ref>
[[File:Selenophenol.png|thumb|left|400px|Benzeneselenol]]

More so that thiophenol, benzeneselenol is easily oxidized by air to give [[diphenyl diselenide]]. An idealized equation for this reaction is:
: 2 PhSeH + O → PhSeSePh + H2O
The presence of the [[diselenide]] is signaled by a yellow coloration in most samples of PhSeH. The diselenide can be converted back to the selenol by reduction followed by acidification of the resulting PhSe-.

PhSeH is ca 7x stronger acid than the related [[thiophenol]]. Both compounds dissolve in water upon the addition of base.

PhSeH is renowned in [[organic synthesis]] as the precursor to its conjugate base PhSe-, a potent [[nucleophile]].<ref>Sonoda, N.; Ogawa, A.; Recupero, F. "Benzeneselenol" in Encyclopedia of Reagents for Organic Synthesis (Ed: L. Paquette) 2004, J. Wiley & Sons, New York. DOI: 10.1002/047084289.</ref>

==History==
Benzeneselenol was first prepared by the reaction of [[benzene]] with [[selenium tetrachloride|SeCl4]] in the presence of [[aluminium trichloride|AlCl3]].<ref>Chabrié, M. Camille “Premiers essays de synthèse de composés organiques séléniés dans la série aromatique” Bull. soc. chim. France, 50, 133 (1888); Ann. chim. phys., (6) 20, 229 (1890)</ref>

==References==
<references/>

[[Category:Selenium compounds]]
[[Category:Aromatic compounds]]
[[ja:ベンゼンセレノール]]

Tert-Butyl hydroperoxide

2010-03-06T11:01:53Z

Su-no-G: +ja

{{DISPLAYTITLE:''tert''-Butyl hydroperoxide}}
{{chembox
| verifiedrevid = 267422879
| ImageFile=TBHP.png
| Name = ''tert''-Butyl hydroperoxide
| Section1 = {{Chembox Identifiers
| Abbreviations = TBHP
| CASNo = 75-91-2
| CASNo_Ref = {{cascite}}
}}
| Section2 = {{Chembox Properties
| Formula = C4H10O2
| MolarMass = 90.12 g/mol
| Appearance = Colourless or pale-yellow liquid
| Density = 0.93 g/ml (70% aq. solution)
| MeltingPt = -1 °C
| BoilingPt = 91 °C (decomp.)
}}
| Section3 = {{Chembox Hazards
| EUClass = O, C
| NFPA-H = 4
| NFPA-F = 4
| NFPA-R = 4
| NFPA-O = ox
| FlashPt = 43 °C
}}
}}

'''''tert''-Butyl hydroperoxide''' is an organic peroxide widely used in a variety of [[oxidation]] processes, for example [[Sharpless epoxidation]]. It is normally supplied as a 69-70% aqueous solution.

==Application==
Industrially, ''tert''-butyl hydroperoxide is used as a starter of [[radical polymerization]].

==See also==
* [[Organic peroxide]]
* [[Peroxy acid]]

==References==
{{reflist}}

{{DEFAULTSORT:Butyl hydroperoxide, tert-}}
[[Category:Organic peroxides]]
[[Category:Reagents for organic chemistry]]
[[Category:Highly Hazardous Chemicals]]

[[de:Tert-Butylhydroperoxid]]
[[fr:Hydroperoxyde de tert-butyle]]
[[id:Tert-Butil hidroperoksida]]
[[ja:Tert-ブチルヒドロペルオキシド]]
[[nl:Tert-butylhydroperoxide]]
[[fi:Tert-butyylihydroperoksidi]]

Dimethyldioxirane

2010-03-06T10:53:43Z

Su-no-G: +ja

{{chembox
|ImageFileL1=DMDO.png
|ImageSizeL1=100px
|ImageFileR1=DMDO-stick.png
|ImageSizeR1=100px
|ImageFile2=DMDO3D.png
|ImageSize2=120px
|IUPACName=3,3-Dimethyldioxirane
|OtherNames=DMDO
|Section1= {{Chembox Identifiers
| CASNo=74087-85-7
| PubChem=115197
| SMILES=CC1(OO1)C
}}
|Section2= {{Chembox Properties
| Formula=C3H6O2
| MolarMass=74.08 g/mol
| Appearance=
| Density=
| MeltingPt=
| BoilingPt=
| Solubility=
}}
|Section3= {{Chembox Hazards
| MainHazards=
| FlashPt=
| Autoignition=
}}
}}

'''Dimethyldioxirane''' (DMDO) is a [[dioxirane]] derived from [[acetone]]. The only dioxirane in common use, it is a [[reagent]] used in [[organic synthesis]].

==Synthesis==
DMDO is not commercially available because of its instability. DMDO can be prepared by the reaction of acetone with [[oxone]], where the [[potassium peroxymonosulfate]] is the active ingredient:<ref>{{OrgSynth | collvol = 9 | collvolpages = 288 | prep = cv9p0288 | year = 1988 | title = Synthesis of epoxides using dimethyldioxirane]: trans-stilbene oxide | author = Robert W. Murray and Megh Singh}}</ref>

:[[File:Preparation of DMDO.png|300px]]

The preparation of DMDO is rather inefficient (typical yields < 3%) and typically only yields a relatively dilute solution in acetone (approximately 0.15 M). However, this is of no consequence, since DMDO is prepared from extremely cheap starting materials: [[acetone]], [[sodium bicarbonate]], and [[potassium peroxymonosulfate]] (commercially known as "oxone"). A freshly prepared solution of DMDO in acetone will last approximately one to two weeks in the freezer. Frequent titrations (typically by 1H NMR with thioanisole) are required.{{Fact|date=March 2009}}

==Uses==
The most common use for DMDO is the [[oxidation]] of [[alkenes]] to [[epoxide]]s. One particular advantage of using DMDO is that the only byproduct of oxidation is acetone, a fairly innocuous and volatile compound. DMDO oxidations are particularly mild, sometimes allowing oxidations which might not otherwise be possible. In fact, DMDO is considered the reagent of choice for epoxidation, and in nearly all circumstances is as good as or better than peroxyacids such as [[meta-Chloroperoxybenzoic acid]] (m-CPBA).

Despite its high reactivity, DMDO displays good selectivity for olefins. Typically, electron deficient olefins are oxidized more slowly than electron rich ones. DMDO will also oxidize several other functional groups. For example, DMDO will oxidize primary [[amine]]s to [[nitro]] compounds and [[sulfide]]s to [[sulfoxide]]s. In some cases, DMDO will even oxidize unactivated C-H bonds:

:[[Image:dioxirane oxidations.png|475px]]

DMDO can also be used to convert [[nitro compound]]s to carbonyl compounds ([[Nef reaction]]).

:[[Image:Nef DMDO.png|200px]]

==References==
<references/>
* Dimethyldioxirane. Crandall, J.K.; Curci, R.; D'Accolti, L.; Fusco, C. ''Encyclopedia of Reagents for Organic Synthesis'' (2005). DOI: 10.1002/047084289X.rd329

[[Category:Reagents for organic chemistry]]
[[Category:Organic peroxides]]
[[Category:Dioxiranes]]

[[ja:ジメチルジオキシラン]]
[[zh:二甲基过氧化酮]]

Benzyl chloroformate

2010-03-06T08:05:42Z

Su-no-G: +ja

{{chembox
| verifiedrevid = 311033559
| ImageFile=Benzyl-chloroformate-2D-skeletal.png
| ImageName = Skeletal formula of benzyl chloroformate
| ImageFile1=Benzyl-chloroformate-3D-balls.png
| ImageName1 = Ball-and-stick model of the benzyl chloroformate molecule
| IUPACName=Benzyloxycarbonyl chloride Benzyl chloroformate
| Section1 = {{Chembox Identifiers
| CASNo_Ref = {{cascite}}
| CASNo=501-53-1
| PubChem=10387
| SMILES=c1ccccc1COC(=O)Cl
}}
| Section2 = {{Chembox Properties
| C=8
| H=7
| Cl=1
| O=2
| Density=1.195 g/cm3
| MeltingPt=0 °C
| BoilingPt=103 °C (20 [[Torr]])
}}
| Section7={{Chembox Hazards
| EUClass={{Hazchem C}}{{Hazchem N}}{{Hazchem Xn}}
| ExternalMSDS = [http://msds.chem.ox.ac.uk/BE/benzyl_chloroformate.html External MSDS]
| EUIndex=607-064-00-4
| RPhrases={{R34}}, {{R50/53}}
| SPhrases={{S1/2}}, {{S26}}, {{S45}}, {{S60}}, {{S61}}
| FlashPt=80 °C
}}
}}

'''Benzyl chloroformate''' is the [[benzyl]] [[ester]] of [[chloroformic acid]]. It is also known as benzyl chlorocarbonate is an oily liquid who color is anywhere from yellow to colorless. It is also known for its pungent odor. Benzyl chloroformate if heated turns into a [[phosgene]] and if it comes in contact with water it produces toxic, corrosive fumes.

Benzyl chloroformate is used in [[organic synthesis]] for the introduction of the [[carboxybenzyl]] (Cbz or Z) [[protecting group]] for [[amine]]s:

:[[File:Cbz.PNG|450px]]

It also is a carcinogen.{{Fact|date=December 2007}}

The newly formed Cbz protecting group can be removed under reductive conditions. Typically hydrogen gas and activated palladium on carbon is used.

== External links ==
*{{ICSC|0990|09}}

[[Category:Chloroformates]]
[[Category:Reagents for organic chemistry]]

{{ester-stub}}

[[id:Benzil kloroformat]]
[[ja:クロロギ酸ベンジル]]
[[nl:Benzylchloorformiaat]]

Chloromethyl methyl ether

2010-03-06T02:31:53Z

Su-no-G: +ja

{{chembox
| verifiedrevid = 329011034
| ImageFile=Chloromethyl methyl ether.svg
| ImageSize=120px
| Reference=<ref>[http://www.sigmaaldrich.com/catalog/ProductDetail.do?N4=100331|ALDRICH&N5=SEARCH_CONCAT_PNO|BRAND_KEY&F=SPEC Sigma-Aldrich]</ref>
| OtherNames = MOM-Cl, CMME
| Section1 = {{Chembox Identifiers
| ChemSpiderID = 7576
| CASNo_Ref = {{cascite}}
| CASNo = 107-30-2
}}
| Section2 = {{Chembox Properties
| C=2|H=5|Cl=1|O=1
| MeltingPt =
| BoilingPt = 55-57 °C
| Density=1.06 g/mL
}}
| Section3 = {{Chembox Hazards
| RPhrases = {{R11}} {{R20/21/22}} {{R45}}
| SPhrases = {{S45}} {{S53}}
| ExternalMSDS =
}}
}}

'''Chloromethyl methyl ether''' is a [[Compound (chemistry)|compound]] with formula CH3OCH2Cl. It is a [[chloroalkyl ether]]. It is used as an [[alkylating agent]] and industrial [[solvent]] to manufacture [[dodecylbenzyl chloride]], [[water repellent]]s, [[ion-exchange resin]]s, [[polymer]]s, and as a chloromethylation [[reagent]]. It is a known human [[carcinogen]].<ref>''bis(Chloromethyl) Ether and Technical-Grade Chloromethyl Methyl Ether CAS Nos. 542-88-1 and 107-30-2'' [http://ntp.niehs.nih.gov/ntp/roc/eleventh/profiles/s039bcme.pdf Report on carcinogens, eleventh edition]</ref> In [[organic synthesis]], it is used from introducing the methoxymethyl (MOM) [[protecting group]].<ref>''Protective Groups in Organic Synthesis'', T. W. Greene and P. G. M. Green, 3rd Edition, pages 27-33. ISBN 0-471-16019-9</ref>

==References==
<references/>

[[Category:Reagents for organic chemistry]]
[[Category:Alkylating agents]]
[[Category:Protecting groups]]
[[Category:Organochlorides]]
[[Category:Ethers]]
[[Category:IARC Group 1 carcinogens]]
[[Category:Highly Hazardous Chemicals]]

[[de:(Chlormethyl)methylether]]
[[nl:Chloormethoxymethaan]]
[[ja:クロロメチルメチルエーテル]]
[[zh:氯甲醚]]

Isotopes of copernicium

2010-02-25T14:15:05Z

Su-no-G: renaming ja

'''[[Copernicium]]''' ('''Cn''') has no stable isotopes. A standard atomic mass cannot be given.

== Table ==
{| class="wikitable" style="font-size:95%; white-space:nowrap"
! rowspan="2" | nuclide symbol
! Z([[proton|p]])
! N([[neutron|n]])
!   isotopic mass (u)  
! rowspan="2" | half-life
! rowspan="2" | nuclear spin
! rowspan="2" | representative isotopic composition (mole fraction)
! rowspan="2" | range of natural variation (mole fraction)
|-
! colspan="3" | excitation energy
|-
| 277Cn
| 112
| 165
| 277.16394(14)#
| 1.1(7) ms [0.69(+69-24) ms]
| 3/2+#
|
|
|-
| 278Cn
| 112
| 166
| 278.16431(57)#
| 10# ms
| 0+
|
|
|-
| 279Cn
| 112
| 167
| 279.16655(53)#
| 0.1# s
|
|
|
|-
| 280Cn
| 112
| 168
| 280.16704(69)#
| 1# s
| 0+
|
|
|-
| 281Cn
| 112
| 169
| 281.16929(106)#
| 10# s
| 3/2+#
|
|
|-
| 282Cn
| 112
| 170
| 282.16977(76)#
| 30# s
| 0+
|
|
|-
| 283Cn
| 112
| 171
| 283.17179(83)#
| 4.2(2.1) min
|
|
|
|-
| 284Cn
| 112
| 172
| 284.17238(91)#
| 31(18) s
| 0+
|
|
|-
| 285Cn
| 112
| 173
| 285.17411(78)#
| 40(30) min
| 5/2+#
|
|
|}

=== Notes ===
* Values marked # are not purely derived from experimental data, but at least partly from systematic trends. Spins with weak assignment arguments are enclosed in parentheses.
* Uncertainties are given in concise form in parentheses after the corresponding last digits. Uncertainty values denote one standard deviation, except isotopic composition and standard atomic mass from IUPAC which use expanded uncertainties.

== References ==
* Isotope masses from [http://www.nndc.bnl.gov/amdc/index.html Ame2003 Atomic Mass Evaluation] by G. Audi, A.H. Wapstra, C. Thibault, J. Blachot and O. Bersillon in ''Nuclear Physics'' A729 (2003).
* Isotopic compositions and standard atomic masses from [http://www.iupac.org/publications/pac/2003/7506/7506x0683.html Atomic weights of the elements. Review 2000 (IUPAC Technical Report)]. ''Pure Appl. Chem.'' Vol. 75, No. 6, pp. 683–800, (2003) and [http://www.iupac.org/news/archives/2005/atomic-weights_revised05.html Atomic Weights Revised (2005)].
* Half-life, spin, and isomer data selected from these sources. Editing notes on this article's talk page.
** Audi, Bersillon, Blachot, Wapstra. [http://amdc.in2p3.fr/web/nubase_en.html The Nubase2003 evaluation of nuclear and decay properties], Nuc. Phys. A 729, pp. 3–128 (2003).
** National Nuclear Data Center, Brookhaven National Laboratory. Information extracted from the [http://www.nndc.bnl.gov/nudat2/ NuDat 2.1 database] (retrieved Sept. 2005).
** David R. Lide (ed.), Norman E. Holden in ''CRC Handbook of Chemistry and Physics, 85th Edition'', online version. CRC Press. Boca Raton, Florida (2005). Section 11, Table of the Isotopes.

{{Isotope nav | element=copernicium | lighter=Isotopes of roentgenium | heavier=Isotopes of ununtrium }}

[[Category:Copernicium]]
[[Category:Isotopes of copernicium|*]]
[[Category:Lists of isotopes by element|Copernicium]]

[[ja:コペルニシウムの同位体]]
[[zh:Cn的同位素]]

Copernicium

2010-02-25T12:14:03Z

Su-no-G: renaming ja

{{Redirect|Uub|the [[Dragon Ball]] character|Uub (character)}}
{{Infobox copernicium}}

'''Copernicium''' is a synthetic [[radioactive]] [[chemical element]] with the symbol '''Cn''' and [[atomic number]] 112. It was first created in 1996 by the {{lang|de|[[Gesellschaft für Schwerionenforschung]] (GSI)}}.

Copernicium is currently the [[transuranium element|highest-numbered element]] to be officially recognised by IUPAC. The most stable isotope discovered to date is 285Cn with a [[half-life]] of ≈30 s, although evidence exists that 285Cn may have a [[nuclear isomer]] with a much longer half-life of 8.9 min. In total, about 75 atoms of copernicium have been detected using various nuclear reactions.<ref>See references in this article relating to 277Cn, 282Cn and 283Cn, as well as references in [[ununquadium]], [[ununhexium]] and [[ununoctium]] regarding observed daughter nuclei</ref> Recent experiments suggest that copernicium behaves as a typical [[Group 12 element|member of group 12]], demonstrating properties consistent with a volatile metal.<ref name=07Ei01>{{cite journal|title=Chemical Characterization of Element 112|author=R. Eichler, et al.|journal=[[Nature (journal)|Nature]]|year=2007|volume=447|pages=72–75 |doi=10.1038/nature05761|pmid=17476264|last1=Eichler|first1=R | last2=Aksenov |first2=NV |last3=Belozerov |first3=AV|last4=Bozhikov|first4=GA|last5=Chepigin|first5=VI|last6=Dmitriev |first6=SN|last7=Dressler|first7=R|last8=Gäggeler|first8=HW |last9=Gorshkov |first9=VA |issue=7140 }}</ref>

GSI proposed the permanent name "Copernicium" after the astronomer [[Nicolaus Copernicus]].<ref>{{cite journal|url=http://old.iupac.org/reports/provisional/abstract09/corish_pr112.pdf|title=NAME AND SYMBOL OF THE ELEMENT WITH ATOMIC NUMBER 112 (For Peer Review Only|author1=Tatsumi, K|author2=Corish, J}}</ref> The name was officially endorsed by the [[IUPAC]] on February 19, 2010, after seven months of discussion.<ref>[http://www.iupac.org/web/nt/2010-02-20_112_Copernicium IUPAC (International Union of Pure and Applied Chemistry): Element 112 is Named Copernicium]</ref> Before that, the element was temporarily named ''ununbium,'' with the symbol Uub. "Ununbium" was an IUPAC [[systematic element name]], used until a permanent name was approved.

==History==
===Official discovery===
Copernicium was [[discovery of the chemical elements|first created]] on February 9, 1996, at the [[Gesellschaft für Schwerionenforschung]] (GSI) in [[Darmstadt]], [[Germany]] by Sigurd Hofmann, [[Victor Ninov]] et al.<ref name=96Ho01/> This element was created by firing accelerated [[zinc]]-70 nuclei at a target made of [[lead]]-208 nuclei in a heavy [[ion accelerator]]. A single atom (the second has subsequently been dismissed) of copernicium was produced with a mass number of 277.<ref name=96Ho01>{{cite journal|title=The new element 112|journal=[[Zeitschrift für Physik]]: A Hadrons and Nuclei|author=S. Hofmann, et al.|volume=354|issue=1|year=1996|pages=229–230|doi=10.1007/BF02769517 }}</ref>

:{{su|p=208|b=82|a=r}}Pb + {{su|p=70|b=30}}Zn → {{su|p=278|b=112}}Cn → {{su|p=277|b=112}}Cn + {{su|p=1|b=0}}n

In May 2000, the GSI successfully repeated the experiment to synthesise a further atom of Cn-277.<ref>{{cite journal|title=New Results on Element 111 and 112|author=Hofmann et al.|journal=[[European Physical Journal]] A Hadrons and Nuclei|year=2002|volume=14|issue=2|pages=147–57|doi=10.1140/epja/i2001-10119-x }}</ref><ref>{{cite journal|url=http://www.gsi.de/informationen/wti/library/scientificreport2000/Nuc_St/7/ar-2000-z111-z112.pdf|title=New Results on Element 111 and 112|author=Hofmann et al.|journal=GSI Scientific Report|year=2000|volume=2000}}</ref>
This reaction was repeated at [[RIKEN]] using the GARIS set-up in 2004 to synthesise two further atoms and confirm the decay data reported by the GSI team.<ref>{{cite conference|conference=Exotic Nuclei (EXON2004)|booktitle=Proceedings of the International Symposium|date=2004|publisher=World Scientific|title=Decay of an Isotope 277112 produced by 208Pb + 70Zn reaction|pages=188–191|author=K. Morita|doi=10.1142/9789812701749_0027}}</ref>

The IUPAC/IUPAP Joint Working Party (JWP) assessed the claim of discovery by the GSI team in 2001<ref>{{cite journal|journal=[[Pure Appl. Chem.]]|volume=73|issue=6|pages=959–967|year=2001|title=On the Discovery of the Elements 110–112|format=IUPAC Technical Report|url=http://www.iupac.org/publications/pac/2001/pdf/7306x0959.pdf|doi=10.1351/pac200173060959|author1=Karol, P. J|author2=Nakahara, H|author3=Petley, B. W|author4=Vogt, E}}</ref> and 2003.<ref>{{cite journal|journal=[[Pure Appl. Chem.]]|volume=75|issue=10|pages=1061–1611|year=2003|title=On the Claims for Discovery of Elements 110, 111, 112, 114, 116 and 118|format=IUPAC Technical Report|url=http://www.iupac.org/publications/pac/2003/pdf/7510x1601.pdf|doi=10.1351/pac200375101601|author1=Karol, P. J|author2=Nakahara, H|author3=Petley, B. W|author4=Vogt, E}}</ref> In both cases, they found that there was insufficient evidence to support their claim. This was primarily related to the contradicting decay data for the known isotope 261Rf. However, between 2001 and 2005, the GSI team studied the reaction 248Cm(26Mg,5n)269Hs, and were able to confirm the decay data for 269Hs and 261Rf. It was found that the existing data on 261Rf was for an isomer,<ref>{{cite web|publisher=[[Paul Scherrer Institute]]|author=R. Dressler; A. Türler|title=Evidence for Isomeric States in 261Rf|url=http://lch.web.psi.ch/pdf/anrep01/B-02heavies.pdf|work=Annual Report 2001|year=2001}}</ref> now designated 261a Rf.

In May 2009, the JWP reported on the claims of discovery of element 112 again and officially recognised the GSI team as the discoverers of element 112.<ref>[http://www.gsi.de/portrait/Pressemeldungen/10062009-1_e.html ]{{Dead link|date=February 2010}}</ref> This decision was based on recent confirmation of the decay properties of daughter nuclei as well as the confirmatory experiments at RIKEN.<ref>{{cite journal|journal=[[Pure Appl. Chem.]]|year=2009|title=Discovery of the element with atomic number 112|format=IUPAC Technical Report|url=http://media.iupac.org/publications/pac/asap/pdf/PAC-REP-08-03-05.pdf|doi=10.1351/PAC-REP-08-03-05|volume=81|page=1331|author1=Barber, R.C|author2=Gaeggeler, H.W|author3=Karol, P.J|author4=Nakahara, H|author5=Vardaci, E|author6=Vogt, E}}</ref>

===Naming===
After acknowledging their discovery, the [[IUPAC]] asked the discovery team at GSI to suggest a permanent name for ununbium.<ref>{{cite web|url=http://www.sciencedaily.com/releases/2009/06/090611210039.htm|title=New Chemical Element In The Periodic Table|publisher=www.sciencedaily.com}}</ref><ref>{{cite journal|doi=10.1351/PAC-REP-08-03-05|title=Discovery of the element with atomic number 112 (IUPAC Technical Report)|year=2009|last1=Barber|first1=Robert C.|last2=Gäggeler|last3=Karol|last4=Nakahara|last5=Vardaci|last6=Vogt|journal=Pure and Applied Chemistry|volume=81|page=1331}}</ref> On 14 July 2009, they proposed ''copernicium'' with the element symbol Cp, after [[Nicolaus Copernicus]] "to honor an outstanding scientist, who changed our view of the world."<ref>{{cite web|url=http://www.gsi.de/portrait/Pressemeldungen/14072009_e.html|date=July 14, 2009|title=Element 112 shall be named "copernicium"|publisher=www.gsi.de}}</ref> [[IUPAC]] delayed the official recognition of the name, pending the results of a six-month discussion period among the scientific community.<ref name="bbc 20090716">[http://news.bbc.co.uk/1/hi/sci/tech/8153596.stm New element named 'copernicium'], BBC News, Thu 16 July 2009</ref><ref>{{cite web|url=http://www.iupac.org/web/nt/2009-07-21_Naming_Element_112|title =News: Start of the Name Approval Process for the Element of Atomic Number 112|publisher=IUPAC}}</ref>

Alternative spellings had been suggested to Hofmann, namely "copernicum", "copernium", and "kopernikium" (Kp), and Hofmann has said that the team had discussed the possibility of "copernicum" or "kopernikum", but that they had agreed on "copernicium" in order to comply with current IUPAC rules, which allow only the suffix ''-ium'' for new elements.<ref>private email from Hofmann</ref>{{Citation needed|date=February 2010}}

However, it was pointed out that the symbol Cp was previously associated with the name ''cassiopeium'' (cassiopium), now known as [[lutetium]] (Lu).<ref>{{cite journal|title=The need for a fresh symbol to designate copernicium|author=Juris Meija|journal=[[Nature (journal)|Nature]]|year=2009|volume=461|page=341|doi=10.1038/461341c|pmid=19759598|last1=Meija|first1=J|issue=7262}}</ref><ref>{{cite web|url=http://elements.vanderkrogt.net/element.php?sym=Lu |title=71. Lutetium - Elementymology & Elements Multidict |publisher=Elements.vanderkrogt.net |date= |accessdate=2010-02-22}}</ref> Furthermore, the symbol Cp is also used in [[organometallic chemistry]] to denote the ligand [[cyclopentadiene]]. For this reason, the IUPAC disallowed the use of Cp as a future symbol, prompting the GSI team to put forward the symbol Cn as an alternative. On February 19, 2010, the 537th anniversary of Copernicus' birth, IUPAC officially accepted the proposed name and symbol.<ref>{{cite web|url=http://news.bbc.co.uk/2/hi/science/nature/8153596.stm |title=Science & Environment | New element named 'copernicium' |publisher=BBC News |date=2009-07-16 |accessdate=2010-02-22}}</ref><ref>{{cite web|url=http://www.iupac.org/web/nt/2010-02-20_112_Copernicium |title=[IUPAC]Element 112 is Named Copernicium |doi=10.1351/PAC-REP-08-03-05 |publisher=Iupac.org |date= |accessdate=2010-02-22}}</ref>

==Isotopes and nuclear properties==
===Nucleosynthesis===
====Target-projectile combinations leading to Z=112 compound nuclei====
The table below contains various combinations of targets and projectiles which could be used to form compound nuclei with Z=112.

{|class="wikitable" style="text-align:center"
|-
! Target !! Projectile !! CN !! Attempt result
|-
!208Pb
|70Zn||278Cn||{{yes|Successful reaction}}
|-
!232Th
|50Ti||282Cn||{{unk|Reaction yet to be attempted}}
|-
!238U
|48Ca||286Cn||{{yes|Successful reaction}}
|-
!244Pu
|40Ar||284Cn||{{unk|Reaction yet to be attempted}}
|-
!248Cm
|36S||284Cn||{{unk|Reaction yet to be attempted}}
|-
!249Cf
|30Si||279Cn||{{unk|Reaction yet to be attempted}}
|}

====Cold fusion====
''This section deals with the synthesis of nuclei of copernicium by so-called "cold" fusion reactions. These are processes which create compound nuclei at low excitation energy (~10–20 MeV, hence "cold"), leading to a higher probability of survival from fission. The excited nucleus then decays to the ground state via the emission of one or two neutrons only.''

=====208Pb(70Zn,xn)278-xCn (x=1)=====
The team at GSI first studied this reaction in 1996 and reported the detection of two decay chains of 277Cn.<ref name=96Ho01/>
In a review of the data in 2000, the first decay chain was retracted. In a repeat of the reaction in 2000 they were able to synthesise a further atom. They attempted to measure the 1n excitation function in 2002 but suffered from a failure of the Zn-70 beam.
The unofficial discovery of 277Cn was confirmed in 2004 at [[RIKEN]], where researchers detected a further two atoms of the isotope and were able to confirm the decay data for the entire chain.

=====208Pb(68Zn,xn)276-xCn=====
After the successful synthesis of 277Cn, the GSI team performed a reaction using a 68Zn projectile in 1997 in an effort to study the effect of [[isospin]] (neutron richness) on the chemical yield. The experiment was initiated after the discovery of a yield enhancement during the synthesis of [[darmstadtium]] isotopes using 62Ni and 64Ni ions. No decay chains of 275Cn were detected leading to a cross section limit of 1.2 pb. However, the revision of the yield for the 70Zn reaction to 0.5 pb does not rule out a similar yield for this reaction.

=====184W(88Sr,xn)272-xCn=====
In 1990, after some early indications for the formation of isotopes of element 112 in the irradiation of a tungsten target with multi-GeV protons, a collaboration between GSI and the University of Jerusalem studied the foregoing reaction. They were able to detect some [[spontaneous fission]] activity and a 12.5 MeV alpha decay, both of which they tentatively assigned to the radiative capture product 272Cn or the 1n evaporation residue 271Cn. Both the TWG and JWP have concluded that a lot more research is required to confirm these conclusions.

====Hot fusion====
''This section deals with the synthesis of nuclei of copernicium by so-called "hot" fusion reactions. These are processes which create compound nuclei at high excitation energy (~40–50 MeV, hence "hot"), leading to a reduced probability of survival from fission and quasi-fission. The excited nucleus then decays to the ground state via the emission of 3–5 neutrons. Fusion reactions utilizing 48Ca nuclei usually produce compound nuclei with intermediate excitation energies (~30–35 MeV) and are sometimes referred to as "warm" fusion reactions. This leads, in part, to relatively high yields from these reactions.''

=====238U(48Ca,xn)286-xCn (x=3,4)=====
In 1998, the team at the Flerov Laboratory of Nuclear Research began a research program using Ca-48 nuclei in "warm" fusion reactions leading to superheavy elements (SHE's).
In March 1998, they claimed to have synthesised the element (two atoms) in this reaction.
The product, 283Cn, had a claimed half-life of 5 min, decaying by spontaneous fission (SF).<ref>{{cite journal|title=Search for new isotopes of element 112 by irradiation of 238U with 48Ca|author=Oganessian et al.|journal=[[Eur. Phys. J.]] A|year=1999|volume=5|issue=1|pages=63–68|doi=10.1007/s100500050257}}</ref>

The long lifetime of the product initiated first chemical experiments on the gas phase atomic chemistry of element 112. In 2000, Yuri Yukashev at Dubna repeated the experiment but was unable to observe any [[spontaneous fission]] from 5 min activities. The experiment was repeated in 2001 and an accumulation of eight fragments resulting from spontaneous fission were found in the low-temperature section, indicating that copernicium had radon-like properties. However, there is now some serious doubt about the origin of these results.

In order to confirm the synthesis, the reaction was successfully repeated by the same team in Jan 2003, confirming the decay mode and half life. They were also able to calculate an estimate of the mass of the spontaneous fission activity to ~285 lending support to the assignment.<ref>{{cite journal|title=Second Experiment at VASSILISSA separator on the synthesis of the element 112|author=Yu Ts Oganessian et al.|journal=[[Eur. Phys. J.]] A|year=2004|volume=19|issue=1|pages=3–6|doi=10.1140/epja/i2003-10113-4}}</ref>

The team at LBNL entered the debate and performed the reaction in 2002. They were unable to detect any spontaneous fission and calculated a cross section limit of 1.6 pb for the detection of a single event.<ref>{{cite journal|author=W. Loveland, K. E. Gregorich, J. B. Patin, D. Peterson, C. Rouki, P. M. Zielinski, and K. Aleklett|title=Search for the production of element 112 in the 48Ca+238U reaction|journal=[[Phys. Rev.]] C|volume=66|issue=4|page=044617|year=2002|doi=10.1103/PhysRevC.66.044617}}</ref>

The reaction was repeated in 2003–2004 by the team at Dubna using a slightly different set-up, the Dubna Gas Filled Recoil Separator (DGFRS). This time, 283Cn was found to decay by emission of a 9.53 MeV alpha-particle with a half-life of 4 seconds. 282Cn was also observed in the 4n channel.<ref name=04Og01>{{cite journal|title=Measurements of cross sections and decay properties of the isotopes of elements 112, 114, and 116 produced in the fusion reactions 233,238U, 242Pu, and 248Cm+48Ca|author=Yu. Ts. Oganessian et al.|journal=[[Phys. Rev.]] C|volume=70|page=064609|year=2004|doi=10.1103/PhysRevC.70.064609}}</ref>

In 2003, the team at GSI entered the debate and performed a search for the five-minute SF activity in chemical experiments. Like the Dubna team, they were able to detect seven SF fragments in the low temperature section. However, these SF events were uncorrelated, suggesting they were not from actual direct SF of copernicium nuclei and raised doubts about the original indications for radon-like properties.<ref>{{cite journal|title=Indication for a gaseous element 112|author=S. Soverna|year=2003|volume=2003|page=187|publisher=GSI Scientific Report|url=http://www.gsi.de/informationen/wti/library/scientificreport2003/files/167.pdf}}</ref> After the announcement from Dubna of different decay properties for 283Cn, the GSI team repeated the experiment in September 2004. They were unable to detect any SF events and calculated a cross section limit of ~ 1.6 pb for the detection of one event, not in contradiction with the reported 2.5 pb yield by Dubna.

In May 2005, the GSI performed a physical experiment and identified a single atom of 283Cn decaying by SF with a short lifetime suggesting a previously unknown SF branch.<ref>{{cite journal|title=Search for Element 112 Using the Hot Fusion Reaction 48Ca + 238U|author=S. Hofmann, et al.|url=http://www.gsi.de/informationen/wti/library/scientificreport2005/PAPERS/NUSTAR-SHE-PHYS-01.pdf|year=2005|volume=2005|page=191|publisher=GSI Scientific Report}}</ref>
However, initial work by Dubna had detected several direct SF events but had assumed that the parent alpha decay had been missed. These results indicated that this was not the case.

In 2006, the new decay data on 283Cn was confirmed by a joint PSI-FLNR experiment aimed at probing the chemical properties of copernicium. Two atoms of 283Cn were observed in the decay of the parent 287Uuq nuclei. The experiment indicated that contrary to previous experiments, copernicium behaves as a typical member of group 12, demonstrating properties of a volatile metal.<ref name=07Ei01/>

Finally, the team at GSI successfully repeated their physical experiment in Jan 2007 and detected three atoms of 283Cn, confirming both the alpha and SF decay modes.<ref>{{cite journal|title=The reaction 48Ca + 238U -> 286112* studied at the GSI-SHIP|author=S. Hofmann et al.|journal=[[Eur. Phys. J.]] A|volume=32|issue=3|pages=251–260|year =2007|doi=10.1140/epja/i2007-10373-x}}</ref>

As such, the 5 min SF activity is still unconfirmed and unidentified. It is possible that it refers to an isomer, namely 283bCn, whose yield is dependent upon the exact production methods.

=====233U(48Ca,xn)281-xCn=====
The team at FLNR studied this reaction in 2004. They were unable to detect any atoms of element 112 and calculated a cross section limit of 600 fb. The team concluded that this indicated that the neutron mass number for the compound nucleus had an effect on the yield of evaporation residues.<ref name=04Og01/>

====As a decay product====
Copernicium has also been observed as decay products of elements 114, 116, and 118 (see [[ununoctium]]).

{|class="wikitable"
|-
! Evaporation Residue !! Observed Cn isotope
|-
|293116, 289114||285Cn
|-
|292116, 288114||284Cn
|-
|291116, 287114||283Cn
|-
|294118, 290116, 286114||282Cn
|}

As an example, in May 2006, the Dubna team ([[Joint Institute for Nuclear Research|JINR]]) identified 282Cn as a final product in the decay of ununoctium via the [[alpha decay]] sequence.

:{{Nuclide2|ununoctium|294}} → {{Nuclide2|ununhexium|290}} → {{Nuclide2|ununquadium|286}} → {{Nuclide2|copernicium|282}}

It was found that the final nucleus undergoes [[spontaneous fission]].<ref>{{cite journal|last=Oganessian|first=Yu. Ts.|coauthors=et al.|title=Synthesis of the isotopes of elements 118 and 116 in the 249Cf and 245Cm+48Ca fusion reactions|journal=Physical Review C|volume=74|issue=4|page=044602|date=2006|doi=10.1103/PhysRevC.74.044602}}</ref>

====Retracted isotopes====
=====281Cn=====
In the claimed synthesis of 293Uuo in 1999 (see [[ununoctium]]) the isotope 281Cn was identified as decaying by emission of a 10.68 MeV alpha particle with half-life 0.90 ms. The claim was retracted in 2001 and hence this copernicium isotope is currently unknown or unconfirmed.

====Chronology of isotope discovery====
{|class="wikitable" style="text-align:center"
|-
! Isotope !! Year discovered !! discovery reaction
|-
|277Cn||1996||208Pb(70Zn,n)
|-
|278Cn||unknown||
|-
|279Cn||unknown||
|-
|280Cn||unknown||
|-
|281Cn||unknown||
|-
|282Cn||2004||238U(48Ca,4n)
|-
|283Cn||2002||244Pu(48Ca,5n)
|-
|283bCn ??||1998||238U(48Ca,3n)
|-
|284Cn||2002||244Pu(48Ca,4n)
|-
|285Cn||1999||244Pu(48Ca,3n)
|-
|285bCn ?||1999||244Pu(48Ca,3n)
|}

===Nuclear isomerism===
====285a,bCn====
In the synthesis of 289Uuq and 293Uuh, a 8.63 MeV alpha-decaying activity has been detected with a half-life of 8.9 minutes. Although unconfirmed in recent experiments, it is highly possible that this is associated with an isomer, namely 285bCn.

====283a,bCn====
First experiments on the synthesis of 283Cn produced a SF activity with half-life ~5 min. This activity was also observed from the alpha decay of 287Uuq. The decay mode and half-life were also confirmed in a repetition of the first experiment. However, more recently,283Cn has been observed to undergo 9.52 MeV alpha decay and SF with a half-life of 3.9 s. These results suggest the assignment of the two activities to two different isomeric levels in 283Cn, creating 283aCn and 283bCn. Further research is required to address these discrepancies.

===Chemical yields of isotopes===
====Cold fusion====
The table below provides cross-sections and excitation energies for [[cold fusion]] reactions producing copernicium isotopes directly. Data in bold represent maxima derived from excitation function measurements. + represents an observed exit channel.

{|class="wikitable"
|-
! Projectile !! Target !! CN !! 1n !! 2n !! 3n
|-
|70Zn||208Pb||278Cn||0.5 pb, 10.0, 12.0 MeV||||
|-
|68Zn||208Pb||276Cn||<1.2 pb, 11.3, 12.8 MeV||||
|}

====Hot fusion====
The table below provides cross-sections and excitation energies for hot fusion reactions producing copernicium isotopes directly. Data in bold represents maxima derived from excitation function measurements. + represents an observed exit channel.

{|class="wikitable"
|-
! Projectile !! Target !! CN !! 3n !! 4n !! 5n
|-
|48Ca||238U||286Cn||'''2.5 pb, 35.0 MeV'''||0.6 pb||
|-
|48Ca||233U||281Cn||<0.6 pb, 34.9 MeV||||
|}

===Fission of compound nuclei with Z=112===
Several experiments have been performed between 2001 and 2004 at the Flerov Laboratory of Nuclear Reactions in Dubna studying the fission characteristics of the compound nucleus 286Cn. The nuclear reaction used is 238U+48Ca. The results have revealed how nuclei such as this fission predominantly by expelling closed shell nuclei such as 132Sn (Z=50, N=82). It was also found that the yield for the fusion-fission pathway was similar between 48Ca and 58Fe projectiles, indicating a possible future use of 58Fe projectiles in superheavy element formation.<ref>see [http://www1.jinr.ru/Reports/Reports_eng_arh.html Flerov lab annual reports 2001–2004]</ref>

===Theoretical calculations===
====Evaporation residue cross sections====
The below table contains various targets-projectile combinations for which calculations have provided estimates for cross section yields from various neutron evaporation channels. The channel with the highest expected yield is given.

DNS = Di-nuclear system; σ = cross section

{|class="wikitable" style="text-align:center"
|-
! Target !! Projectile !! CN !! Channel (product) !! σmax !! Model !! Ref
|-
!208Pb
|70Zn||278Cn||1n (277Cn)||1.5 pb||DNS||<ref name=FengColdFusion> {{cite journal|doi = 10.1103/PhysRevC.76.044606 | url = http://arxiv.org/pdf/0707.2588 | title = Formation of superheavy nuclei in cold fusion reactions|year = 2007|author = Feng, Zhao-Qing|journal = Physical Review C|volume = 76|page = 044606}}</ref>
|-
!208Pb
|67Zn||275Cn||1n (274Cn)||2 pb||DNS||<ref name=FengColdFusion />
|-
!238U
|48Ca||286Cn||4n (282Cn)||0.2 pb||DNS||<ref name=FengEntranceChannel >{{cite journal|doi =|url = http://arxiv.org/pdf/0904.2994 |title = Influence of entrance channels on formation of superheavy nuclei in massive fusion reactions}}</ref>
|-
!244Pu
|40Ar||284Cn||4n (280Cn)||0.1 pb||DNS||<ref name=FengEntranceChannel />
|-
!250Cm
|36S||286Cn||4n (282cn)||5 pb||DNS||<ref name=FengEntranceChannel />
|-
!252Cf
|30Si||282Cn||3n (279Cn)||10 pb||DNS||<ref name=FengEntranceChannel />
|}

==Chemical properties==
===Extrapolated chemical properties===
====Oxidation states====
Copernicium is the last member of the 6d series of transition metals and the heaviest member of group 12 (IIB) in the Periodic Table, below [[zinc]], [[cadmium]] and [[mercury (element)|mercury]]. Each of the members of this group show a stable +2 oxidation state. In addition, mercury(I), {{chem|Hg|2|2+}}, is also well known. Copernicium is therefore expected to form a stable +2 state.

====Chemistry====
The known members of group 12 all react with [[oxygen]] and [[sulfur]] directly to form the [[oxide]]s and [[sulfide]]s, MO and MS, respectively. Mercury(II) oxide, HgO, can be decomposed by heat to the liquid metal. Mercury also has a well known affinity for sulfur. Therefore, copernicium should form an analogous oxide CnO and sulfide CnS.

In their [[halogen]] chemistry, all the metals form the ionic difluoride MF2 upon reaction with [[fluorine]]. The other halides are known but for mercury, the soft nature of the Hg(II) ion leads to a high degree of [[covalency]] and HgCl2, HgBr2 and HgI2 are low-melting, volatile solids. Therefore, copernicium is expected to form an ionic fluoride, CnF2, but volatile halides, CnCl2, CnBr2 and CnI2.

In addition, mercury is well known for its [[alloy]]ing properties, with the concomitant formation of [[amalgam (chemistry)|amalgams]], especially with [[gold]] and [[silver]]. It is also a volatile metal and is [[monatomic]] in the [[vapour]] [[phase (matter)|phase]]. Copernicium is therefore also predicted to be a volatile metal which readily combines with gold to form a Au-Cn metal-metal bond.

===Experimental chemistry===
====Atomic gas phase====
Copernicium has the ground state electron configuration [Rn]5f14 6d10 7s2 and thus belongs to group 12 of the Periodic Table. As such, it should behave as the heavier homologue of mercury (Hg) and form strong binary compounds with noble metals like gold. Experiments probing the reactivity of copernicium have focused on the adsorption of atoms of element 112 onto a gold surface held at varying temperatures, in order to calculate an adsorption enthalpy. Due to possible relativistic stabilisation of the 7s electrons, leading to radon-like properties, experiments were performed with the simultaneous formation of mercury and radon radioisotopes, allowing a comparison of adsorption characteristics.

The first experiments were conducted using the 238U(48Ca,3n)283Cn reaction. Detection was by spontaneous fission of the claimed 5 min parent isotope. Analysis of the data indicated that copernicium was more volatile than mercury and had noble-gas properties. However, the confusion regarding the synthesis of 283Cn has cast some doubt on these experimental results.

Given this uncertainty, between April-May 2006 at the JINR, a FLNR-PSI team conducted experiments probing the synthesis of this isotope as a daughter in the nuclear reaction 242Pu(48Ca,3n)287Uuq. In this experiment, two atoms of 283Cn were unambiguously identified and the adsorption properties indicated that copernicium is a more volatile homologue of mercury, due to formation of a weak metal-metal bond with gold, placing it firmly in group 12.

In April 2007 this experiment was repeated and a further three atoms of 283Cn were positively identified. The adsorption property was confirmed and indicated that copernicium has adsorption properties completely in agreement with being the heaviest member of group 12.<ref>{{cite web|author=H. W. Gäggeler| title=Gas Phase Chemistry of Superheavy Elements|date=2007|publisher=[[Paul Scherrer Institute]]|url=http://lch.web.psi.ch/pdf/TexasA&M/TexasA&M.pdf}}</ref>

==See also==
*[[Island of stability]]

==References==
{{clear}}
{{Reflist|colwidth=30em}}

==External links==
{{Wiktionary|copernicium}}
{{Commons|copernicium}}
*[http://www.webelements.com/copernicium/ WebElements.com: Copernicium]

{{compact periodic table}}

[[Category:Chemical elements]]
[[Category:Transition metals]]
[[Category:Post-transition metals]]
[[Category:Synthetic elements]]
[[Category:Nuclear physics]]
[[Category:Ununbium]]

[[ar:أنون بيوم]]
[[ast:Copernicium]]
[[bn:ইউনুনবিয়াম]]
[[be:Каперніцый]]
[[bs:Ununbijum]]
[[bg:Коперниций]]
[[ca:Copernici]]
[[cv:Коперници]]
[[cs:Copernicium]]
[[co:Ununbiu]]
[[cy:Coperniciwm]]
[[da:Copernicium]]
[[de:Copernicium]]
[[et:Koperniitsium]]
[[el:Κοπερνίκιο]]
[[es:Copernicio]]
[[eo:Kopernicio]]
[[eu:Kopernizio]]
[[fa:کوپرنیسیم]]
[[fr:Copernicium]]
[[fur:Ununbium]]
[[gv:Oonoonbium]]
[[gl:Ununbio]]
[[ko:코페르니슘]]
[[hr:Ununbij]]
[[id:Ununbium]]
[[it:Copernicio]]
[[he:קופרניקיום]]
[[sw:Ununbi]]
[[ku:Ûnûnbiyûm]]
[[la:Copernicium]]
[[lv:Kopernikijs]]
[[lb:Ununbium]]
[[lij:Ununbio]]
[[hu:Ununbium]]
[[ml:കോപ്പർനിസിയം]]
[[nl:Copernicium]]
[[ja:コペルシニウム]]
[[no:Copernicium]]
[[nn:Ununbium]]
[[nds:Ununbium]]
[[pl:Copernicium]]
[[pt:Copernício]]
[[ro:Coperniciu]]
[[qu:Ununbiyu]]
[[ru:Коперниций]]
[[stq:Ununbium]]
[[scn:Ununbiu]]
[[simple:Copernicium]]
[[sk:Kopernikium]]
[[sl:Kopernicij]]
[[sr:Коперницијум]]
[[sh:Ununbijum]]
[[fi:Copernicium]]
[[sv:Copernicium]]
[[ta:கோப்பர்நீசியம்]]
[[th:โคเปอร์นิเซียม]]
[[tr:Ununbiyum]]
[[uk:Коперницій]]
[[ug:Ununbium]]
[[war:Copernicium]]
[[yo:Ununbium]]
[[zh:Copernicium]]

Tamoxifen

2009-12-05T12:50:24Z

Su-no-G: modifying ja

{{drugbox
| verifiedrevid = 306848559
| IUPAC_name = (''Z'')-2-[4-(1,2-diphenylbut-1-enyl)phenoxy]-''N'',''N''-dimethyl-ethanamine
| image = Tamoxifen Structural Formulae.png
| image2 = Tamoxifen-3D-balls.png
| CASNo_Ref = {{cascite}}
| CAS_number = 10540-29-1
| ChemSpiderID = 2015313
| ATC_prefix = L02
| ATC_suffix = BA01
| PubChem = 5376
| DrugBank = APRD00123
| C = 26 |H = 29 |N = 1 |O = 1
| molecular_weight = 371.515 g/mol 563.638 g/mol ([[citrate]] salt)
| bioavailability =
| protein_bound =
| metabolism = [[Liver|Hepatic]] ([[CYP3A4]], [[CYP2C9|2C9]] and [[CYP2D6|2D6]])
| elimination_half-life = 5–7 days
| excretion = Fecal
| pregnancy_category = B3 ([[Australia|Au]]) D ([[United States|US]])
| legal_UK = POM
| legal_US = Rx-only
| routes_of_administration = Oral
}}
'''Tamoxifen''' is an [[receptor antagonist|antagonist]] of the [[estrogen receptor]] in breast tissue. It has been the standard endocrine (anti-estrogen) therapy for hormone-positive early [[breast cancer]], although [[aromatase inhibitors]] have been proposed for postmenopausal women.<ref name=BIG>[http://content.nejm.org/cgi/content/full/361/8/766 Letrozole Therapy Alone or in Sequence with Tamoxifen in Women with Breast Cancer], The BIG 1-98 Collaborative Group, N Engl J Med, 361:766 Aug. 20, 2009</ref>

Some breast cancer cells require estrogen to grow. Estrogen binds to and activates the estrogen receptor in these cells. Tamoxifen is metabolized into compounds that also bind to the estrogen receptor but do not activate it. Furthermore tamoxifen prevents estrogen from binding to its receptor. Hence breast cancer cell growth is blocked.

Tamoxifen was discovered by [[Imperial Chemical Industries|ICI]] Pharmaceuticals<ref name="Jordan_2006">{{cite journal |author=Jordan VC|title=Tamoxifen (ICI46,474) as a targeted therapy to treat and prevent breast cancer|journal= Br J Pharmacol |volume= 147 |issue= Suppl 1 |pages= S269–76 |year= 2006 | doi = 10.1038/sj.bjp.0706399 |pmid= 16402113}}</ref> (now [[AstraZeneca]]) and is sold under the trade names '''Nolvadex''', '''Istubal''', and '''Valodex'''. However, the drug, even before its patent expiration, was and still is widely referred to by its generic name "tamoxifen."

== Breast cancer treatment ==

Tamoxifen is currently used for the treatment of both early and advanced ER+ (estrogen receptor positive) breast cancer in pre- and post-[[menopausal]] women.<ref name="Jordan_1993">{{cite journal |author=Jordan VC|title=Fourteenth Gaddum Memorial Lecture. A current view of tamoxifen for the treatment and prevention of breast cancer|journal= Br J Pharmacol |volume= 110 |issue= 2 |pages= 507–17 |year= 1993 | doi = |pmid= 8242225}}</ref> Additionally, it is the most common hormone treatment for male breast cancer.<ref name="urlBreast cancer in men: Cancer Research UK: CancerHelp UK">{{cite web | url = http://www.cancerhelp.org.uk/help/default.asp?page=5075 | title = Breast cancer in men | author = | authorlink = | coauthors = | date = 2007-09-28 | format = | work = CancerHelp UK | publisher = Cancer Research UK | pages = | language = | archiveurl = | archivedate = | quote = | accessdate = 2009-03-22}}</ref> It is also approved by the [[Food and Drug Administration|FDA]] for the prevention of breast cancer in women at high risk of developing the disease.<ref name="FDA">{{cite web | url = http://www.fda.gov/cder/news/tamoxifen/| title = Tamoxifen Information: reducing the incidence of breast cancer in women at high risk | dateformat = mdy | accessdate = July 3 2007| author = Center for Drug Evaluation and Research | date = 03/08/2005 | publisher = U.S. Food and Drug Administration}}</ref> It has been further approved for the reduction of contralateral (in the opposite breast) cancer.

=== Comparative studies ===

In 2006, the large STAR clinical study concluded that [[raloxifene]] is equally effective in reducing the incidence of breast cancer, but after an average 4-year follow-up there were 36 % fewer [[uterine cancer]]s and 29 % fewer blood clots in women taking raloxifene than in women taking tamoxifen, although the difference is not statistically significant.<ref name="NCI">{{cite web | url = http://www.cancer.gov/star| title = Study of Tamoxifen and Raloxifene (STAR) Trial | dateformat = mdy | accessdate = July 3 2007| author = National Cancer Institute | date = 2006-04-26 | publisher = U.S. National Institutes of Health}}</ref><ref name="STAR">{{cite web | url = http://www.nsabp.pitt.edu/STAR/Index.html| title = STAR Study of Tamoxifen and Raloxifen | dateformat = mdy | accessdate = July 3 2007| author = University of Pittsburgh | date = | publisher = }}</ref><ref>{{cite web | url = http://www.dslrf.org/breastcancer/content.asp?L2=2&L3=6&SID=130&CID=391&PID=14&CATID=0 | title = Study Finds New Use for Raloxifene: Reducing Breast Cancer in High-Risk Postmenopausal Women | dateformat = mdy | accessdate = March 19 2009 | author = Dr [[Susan Love]] | date = April 22 2006}}</ref>

In 2005, the [[ATAC]] trial showed that after average 68 months following a 5 year adjuvant treatment, the group that received [[anastrozole]] ([[Arimidex]]) had significantly better results than the tamoxifen group. Data from the trial suggest that anastrozole should be the preferred medication for postmenopausal women with localized breast cancer that is [[estrogen receptor]] (ER) positive.<ref name="pmid15639680">{{cite journal | author = Howell A, Cuzick J, Baum M, Buzdar A, Dowsett M, Forbes JF, Hoctin-Boes G, Houghton J, Locker GY, Tobias JS | title = Results of the ATAC (Arimidex, Tamoxifen, Alone or in Combination) trial after completion of 5 years' adjuvant treatment for breast cancer | journal = Lancet | volume = 365 | issue = 9453 | pages = 60–2 | year = 2005 | pmid = 15639680 | doi = 10.1016/S0140-6736(04)17666-6 }}</ref> Another study found that the risk of recurrence was reduced 40% (with some risk of bone fracture) and that ER negative patients also benefited from switching to anastrozole.<ref name="urlArimidex After Two Years of Tamoxifen Reduces Recurrence in Post-Menopausal Women">{{cite web | url = http://www.breastcancer.org/treatment/hormonal/new_research/20051003.jsp | title = Arimidex After Two Years of Tamoxifen Reduces Recurrence in Post-Menopausal Women | author = | authorlink = | coauthors = | date = | format = | work = | publisher = BreastCancer.org| pages = | language = | archiveurl = | archivedate = | quote = | accessdate = 2008-11-14}}</ref><ref name="pmid16084253">{{cite journal | author = Jakesz R, Jonat W, Gnant M, Mittlboeck M, Greil R, Tausch C, Hilfrich J, Kwasny W, Menzel C, Samonigg H, Seifert M, Gademann G, Kaufmann M, Wolfgang J; ABCSG and the GABG | title = Switching of postmenopausal women with endocrine-responsive early breast cancer to anastrozole after 2 years' adjuvant tamoxifen: combined results of ABCSG trial 8 and ARNO 95 trial | journal = Lancet | volume = 366 | issue = 9484 | pages = 455–62 | year = 2005 | pmid = 16084253 | doi = 10.1016/S0140-6736(05)67059-6 | url = }}</ref>

== Other uses ==
=== Infertility ===

Tamoxifen is used to treat infertility in women with [[Anovulatory cycle|anovulatory]] disorders. A dose of 10–40 mg per day is administered in days 3–7 of a woman's cycle.<ref name="Steiner_2005">{{cite journal |author=Steiner AZ, Terplan M, Paulson RJ |title=Comparison of tamoxifen and clomiphene citrate for ovulation induction: a meta-analysis |journal=Hum. Reprod. |volume=20 |issue=6 |pages=1511–5 |year=2005 |pmid=15845599 |doi=10.1093/humrep/deh840}}</ref> In addition, a rare condition occasionally treated with tamoxifen is [[retroperitoneal fibrosis]].<ref name="pmid16418409">{{cite journal |author=van Bommel EF, Hendriksz TR, Huiskes AW, Zeegers AG |title=Brief communication: tamoxifen therapy for nonmalignant retroperitoneal fibrosis |journal=Ann. Intern. Med. |volume=144 |issue=2 |pages=101–6 |year=2006 |pmid=16418409 |doi= |issn=}}</ref>

=== Gynecomastia ===

In men, tamoxifen is sometimes used to treat [[gynecomastia]] that arises for example as a side effect of [[antiandrogen]] [[prostate cancer]] treatment.<ref name="Ferraris_2005">{{cite journal |author=Boccardo F, Rubagotti A, Battaglia M, Di Tonno P, Selvaggi FP, Conti G, Comeri G, Bertaccini A, Martorana G, Galassi P, Zattoni F, Macchiarella A, Siragusa A, Muscas G, Durand F, Potenzoni D, Manganelli A, Ferraris V, Montefiore F|title=Evaluation of tamoxifen and anastrozole in the prevention of gynecomastia and breast pain induced by bicalutamide monotherapy of prostate cancer|journal= J Clin Oncol |volume= 23 |issue= 4 |pages= 808–15 |year= 2005 | doi = 10.1200/JCO.2005.12.013 |pmid= 15681525}}</ref> Tamoxifen is also used by bodybuilders<ref>[http://www.gynecomastia-gyno.com/gynecomastia-treatment-options/ Gynecomastia-Gyno.com: Realistic Treatment Options]</ref> to prevent or reduce drug-induced gynecomastia caused by the [[estrogenic]] metabolites of [[anabolic steroids]].<ref name="pmid17098591">{{cite journal |author=Baker JS, Graham MR, Davies B |title=Steroid and prescription medicine abuse in the health and fitness community: A regional study |journal=Eur. J. Intern. Med. |volume=17 |issue=7 |pages=479–84 |year=2006 |pmid=17098591 |doi=10.1016/j.ejim.2006.04.010}}</ref>
Tamoxifen is also sometimes used to treat or prevent gynecomastia in [[sex offender]]s undergoing treatment by temporary [[chemical castration]].<ref name="Guardian_chemical_castration">{{cite web |author=Sample, Ian |date=2007-06-13 |title=Q&A: Chemical castration |publisher=[[Guardian Unlimited]] |url=http://www.guardian.co.uk/theissues/article/0,,2102029,00.html |accessdate=2007-09-10}}</ref>

=== Bipolar disorder ===

Tamoxifen has been shown to be effective in the treatment of [[mania]] in patients with [[bipolar disorder]] by blocking [[protein kinase C]] (PKC), an [[enzyme]] that regulates [[neuron]] activity in the [[brain]]. Researchers believe PKC is over-active during the mania in bipolar patients.<ref name="nimh">{{cite web |publisher= [[National Institutes of Mental Health]] |title= Manic Phase of Bipolar Disorder Benefits from Breast Cancer Medication |url= http://www.nimh.nih.gov/science-news/2007/manic-phase-of-bipolar-disorder-benefits-from-breast-cancer-medication.shtml |date= [[September 12]], [[2007]] |accessdate= 2008-03-10 }}</ref><ref name="pmid18316672">{{cite journal |author=Yildiz A, Guleryuz S, Ankerst DP, Ongür D, Renshaw PF |title=Protein kinase C inhibition in the treatment of mania: a double-blind, placebo-controlled trial of tamoxifen |journal=Arch. Gen. Psychiatry |volume=65 |issue=3 |pages=255–63 |year=2008 |pmid=18316672 |doi=10.1001/archgenpsychiatry.2007.43}}</ref>

=== Angiogenesis and cancer ===

Tamoxifen is one of three drugs in an [[angiogenesis inhibitor|anti-angiogenetic]] protocol developed by [[Judah Folkman|Dr. Judah Folkman]], a researcher at Children's Hospital at Harvard Medical School in Boston. Folkman discovered in the 1970s that [[angiogenesis]] – the growth of new blood vessels – plays a significant role in the development of cancer. Since his discovery, an entirely new field of cancer research has developed. Clinical trials on [[angiogenesis inhibitor]]s have been underway since 1992 using a myriad of different drugs. The Harvard researchers developed a specific protocol for a golden retriever named Navy who was cancer-free after receiving the prescribed cocktail of [[celecoxib]], [[doxycycline]], and tamoxifen – the treatment subsequently became known as the Navy Protocol.<ref name="urlUSA_Today">{{cite web | url = http://www.usatoday.com/news/health/2002-07-24-cover-cancer_x.htm | title = Dog's tale of survival opens door in cancer research | author = Kirk E | authorlink = | coauthors = | date = 2002-07-24 | work = Health and Behavior | publisher = USA Today | pages = | language = | archiveurl = | archivedate = | quote = | accessdate = 2008-06-24}}</ref> Furthermore tamoxifen treatment alone has been shown to have anti-angiogenetic effects in animal models of cancer which appear to be, at least in part, independent of tamoxifen's [[estrogen receptor]] antagonist properties.<ref name="pmid11106254">{{cite journal | author = Blackwell KL, Haroon ZA, Shan S, Saito W, Broadwater G, Greenberg CS, Dewhirst MW | title = Tamoxifen inhibits angiogenesis in estrogen receptor-negative animal models | journal = Clin. Cancer Res. | volume = 6 | issue = 11 | pages = 4359–64 | year = 2000 | month = November | pmid = 11106254 | doi = | url = http://clincancerres.aacrjournals.org/cgi/content/abstract/6/11/4359 | issn = }}</ref>

=== Control of gene expression ===

Tamoxifen is used as a research tool to trigger tissue specific gene expression in many conditional expression constructs in genetically modified animals including a version of the [[Cre-Lox recombination]] technique.<ref name="pmid8855277">{{cite journal |author=Feil R, Brocard J, Mascrez B, LeMeur M, Metzger D, Chambon P |title=Ligand-activated site-specific recombination in mice |journal=Proc. Natl. Acad. Sci. U.S.A. |volume=93 |issue=20 |pages=10887–90 |year=1996 |pmid=8855277 |doi= 10.1073/pnas.93.20.10887}}</ref>

== Mechanism of action ==
[[Image:3ert.png|thumbnail|right|270px|X-ray crystal structure ({{PDB|3ERT}}) of 4-hydroxytamoxifen (white sticks) complexed with the ligand binding domain of the estrogen receptor (cyan cartoon diagram).]]

Tamoxifen competitively binds to estrogen receptors on tumors and other tissue targets, producing a nuclear complex that decreases DNA synthesis and inhibits estrogen effects. It is a nonsteroidal agent with potent antiestrogenic properties which compete with estrogen for [[Cell signaling|binding sites]] in breast and other tissues. Tamoxifen causes cells to remain in the G0 and G1 phases of the [[cell cycle]]. Because it prevents (pre)cancerous cells from dividing but does not cause cell death, tamoxifen is cytostatic rather than cytocidal.

Tamoxifen itself is a [[prodrug]], having relatively little affinity for its target protein, the [[estrogen receptor]]. It is metabolized in the liver by the [[cytochrome P450]] isoform [[CYP2D6]] and [[CYP3A4]] into active metabolites such as 4-hydroxytamoxifen and N-desmethyl-4-hydroxytamoxifen (endoxifen)<ref name="Desta_2004">{{cite journal |author=Desta Z, Ward BA, Soukhova NV, Flockhart DA|title=Comprehensive evaluation of tamoxifen sequential biotransformation by the human cytochrome P450 system in vitro: prominent roles for CYP3A and CYP2D6|journal= J Pharmacol Exp Ther |volume= 310 |issue= 3 |pages= 1062–75 |year= 2004 | doi = 10.1124/jpet.104.065607 |pmid= 15159443}}</ref> which have 30-100 times more affinity with the estrogen receptor than tamoxifen itself. These active metabolites compete with estrogen in the body for binding to the [[estrogen receptor]]. In breast tissue, 4-hydroxytamoxifen acts as an estrogen receptor [[receptor antagonist|antagonist]] so that transcription of estrogen-responsive genes is inhibited.<ref name="Wang_2004">{{cite journal |author=Wang DY, Fulthorpe R, Liss SN, Edwards EA|title=Identification of estrogen-responsive genes by complementary deoxyribonucleic acid microarray and characterization of a novel early estrogen-induced gene: EEIG1|journal=Mol Endocrinol |volume= 18 |issue= 2 |pages= 402–11 |year= 2004 | doi = 10.1210/me.2003-0202 |pmid= 14605097}}</ref>

Tamoxifen binds to estrogen receptor (ER) which in turn interacts with DNA. The ER/tamoxifen complex recruits other proteins known as [[corepressor (genetics)|co-repressors]] to stop genes being switched on by estrogen. Some of these proteins include [[nuclear receptor co-repressor 1|NCoR]] and [[nuclear receptor co-repressor 2|SMRT]].<ref name="pmid11136970">{{cite journal | author = Shang Y, Hu X, DiRenzo J, Lazar MA, Brown M | title = Cofactor dynamics and sufficiency in estrogen receptor-regulated transcription | journal = Cell | volume = 103 | issue = 6 | pages = 843–52 | year = 2000 | month = December | pmid = 11136970 | doi = 10.1016/S0092-8674(00)00188-4 | url = }}</ref> Tamoxifen function can be regulated by a number of different variables including growth factors.<ref name="pmid18245484">{{cite journal | author = Massarweh S, Osborne CK, Creighton CJ, Qin L, Tsimelzon A, Huang S, Weiss H, Rimawi M, Schiff R | title = Tamoxifen resistance in breast tumors is driven by growth factor receptor signaling with repression of classic estrogen receptor genomic function | journal = Cancer Res. | volume = 68 | issue = 3 | pages = 826–33 | year = 2008 | month = February | pmid = 18245484 | doi = 10.1158/0008-5472.CAN-07-2707 | url = }}</ref> Tamoxifen needs to block growth factor proteins such as [[ERBB2|ErbB2/HER2]]<ref name="Hurtado_2008">{{cite journal | author = Hurtado A, Holmes KA, Geistlinger TR, Hutcheson IR, Nicholson RI, Brown M, Jiang J, Howat WJ, Ali S, Carroll JS | title = Regulation of ERBB2 by oestrogen receptor-PAX2 determines response to tamoxifen | journal = Nature | volume = 456 | issue = 7222 | pages = 663–6 | year = 2008 | month = December | pmid = 19005469 | doi = 10.1038/nature07483 | url = }}</ref> because high levels of ErbB2 have been shown to occur in tamoxifen resistant cancers.<ref name="pmid12618500">{{cite journal | author = Osborne CK, Bardou V, Hopp TA, Chamness GC, Hilsenbeck SG, Fuqua SA, Wong J, Allred DC, Clark GM, Schiff R | title = Role of the estrogen receptor coactivator AIB1 (SRC-3) and HER-2/neu in tamoxifen resistance in breast cancer | journal = J. Natl. Cancer Inst. | volume = 95 | issue = 5 | pages = 353–61 | year = 2003 | month = March | pmid = 12618500 | doi = 10.1093/jnci/95.5.353 | url = }}</ref> Tamoxifen seems to require a protein [[PAX2]] for its full anticancer effect.<ref name="Hurtado_2008">{{cite journal | author = Hurtado1 A, Holmes KA, Geistlinger TR, Hutcheson IR, Nicholson RI, Brown M, Jiang J, Howat1 WJ, Ali S, Carroll JS | title = Regulation of ERBB2 by oestrogen receptor–PAX2 determines response to tamoxifen | journal = Nature | volume = 456 | issue = | pages =663| year = 2008 | month = November | pmid = | doi = 10.1038/nature07483 | url = }}</ref><ref name="urlwww.modernmedicine.com">{{cite web | url =http://www.modernmedicine.com/modernmedicine/Modern+Medicine+Now/New-Mechanism-Predicts-Tamoxifen-Response/ArticleNewsFeed/Article/detail/565990 | title = New Mechanism Predicts Tamoxifen Response: PAX2 gene implicated in tamoxifen-induced inhibition of ERBB2/HER2-mediated tumor growth | author = | authorlink = | coauthors = | date = 2008-11-13 | format = | work = | publisher = www.modernmedicine.com | pages = | language = | archiveurl = | archivedate = | quote = | accessdate = 2008-11-14}}</ref> In the presence of high PAX2 expression, the tamoxifen/estrogen receptor complex is able to suppress the expression of the pro-proliferative [[HER2/neu|ERBB2]] protein. In contrast, when AIB-1 expression is higher than PAX2, tamoxifen/estrogen receptor complex upregulates the expression of ERBB2 resulting in stimulation of breast cancer growth.<ref name="Hurtado_2008"/><ref name="urlCORDIS : News">{{cite web | url = http://cordis.europa.eu/fetch?CALLER=EN_NEWS&ACTION=D&SESSION=&RCN=30093 | title = Study sheds new light on tamoxifen resistance | author = | authorlink = | coauthors = | date = | format = | work = News | publisher = CORDIS News | pages = | language = | archiveurl = | archivedate = | quote = | accessdate = 2008-11-14}}</ref>

== Side effects ==
A report in September 2009 from Health and Human Services' Agency for Healthcare Research and Quality suggests that tamoxifen, raloxifene, and tibolone used to treat breast cancer significantly reduce invasive breast cancer in midlife and older women, but also increase the risk of adverse side effects.<ref>{{cite web| url=http://www.oncogenetics.org/web/Medications-Effective-in-Reducing-Risk-of-Breast-Cancer-But-Increase-Risk-of-Adverse-Effects | title=Medications Effective in Reducing Risk of Breast Cancer But Increase Risk of Adverse Effects | author=OncoGenetics.Org| publisher=OncoGenetics.Org| accessdate=2009-09-14| month=September | year=2009}}</ref>

=== Bone ===

A beneficial side effect of tamoxifen is that it prevents bone loss by acting as an estrogen receptor [[agonist]] (i.e., mimicking the effects of estrogen) in this cell type. Therefore, by inhibiting [[osteoclasts]], it prevents [[osteoporosis]].<ref name="pmid17803905">{{cite journal | author = Nakamura T, Imai Y, Matsumoto T, Sato S, Takeuchi K, Igarashi K, Harada Y, Azuma Y, Krust A, Yamamoto Y, Nishina H, Takeda S, Takayanagi H, Metzger D, Kanno J, Takaoka K, Martin TJ, Chambon P, Kato S | title = Estrogen prevents bone loss via estrogen receptor alpha and induction of Fas ligand in osteoclasts | journal = Cell | volume = 130 | issue = 5 | pages = 811–23 | year = 2007 | pmid = 17803905 | doi = 10.1016/j.cell.2007.07.025 }}</ref><ref name="pmid18219273">{{cite journal | author = Krum SA, Miranda-Carboni GA, Hauschka PV, Carroll JS, Lane TF, Freedman LP, Brown M | title = Estrogen protects bone by inducing Fas ligand in osteoblasts to regulate osteoclast survival | journal = Embo J. | volume = 27 | issue = 3 | pages = 535–45 | year = 2008 | pmid = 18219273 | doi = 10.1038/sj.emboj.7601984 }}</ref> When tamoxifen was launched as a drug, it was thought that tamoxifen would act as an estrogen receptor antagonist in all tissue, including bone, and therefore it was feared that it would contribute to osteoporosis. It was therefore very surprising that the opposite effect was observed clinically. Hence tamoxifen's tissue selective action directly led to the formulation of the concept of [[selective estrogen receptor modulator]]s (SERMs).<ref name="Mincey_2000">{{cite journal |author=Mincey BA, Moraghan TJ, Perez EA|title = Prevention and treatment of osteoporosis in women with breast cancer|journal= Mayo Clin Proc |volume= 75 |issue= 8 |pages= 821–9 |year= 2000 | doi = 10.4065/75.8.821|pmid= 10943237 | url = http://www.mayoclinicproceedings.com/inside.asp?ref=7508r |format={{Dead link|date=March 2009}} – [http://scholar.google.co.uk/scholar?hl=en&lr=&q=intitle%3APrevention+and+treatment+of+osteoporosis+in+women+with+breast+cancer&as_publication=Mayo+Clin+Proc&as_ylo=2000&as_yhi=2000&btnG=Search Scholar search]}}</ref> In contrast tamoxifen appears to be associated with bone loss in premenopausal women who continue to menstruate after adjuvant chemotherapy.<ref name="pmid16446340">{{cite journal | author = Vehmanen L, Elomaa I, Blomqvist C, Saarto T | title = Tamoxifen treatment after adjuvant chemotherapy has opposite effects on bone mineral density in premenopausal patients depending on menstrual status | journal = J. Clin. Oncol. | volume = 24 | issue = 4 | pages = 675–80 | year = 2006 | month = February | pmid = 16446340 | doi = 10.1200/JCO.2005.02.3515 | url = }}</ref>

=== Endometrial cancer ===

Tamoxifen is a selective estrogen receptor modulator.<ref name="Gallo_1997">{{cite journal |author=Gallo MA, Kaufman D|title=Antagonistic and agonistic effects of tamoxifen: significance in human cancer|journal= Semin Oncol |volume= 24 |issue= Suppl 1 |pages= S1–71–S1–80 |year= 1997 | doi = |pmid= 9045319}}</ref> Even though it is an [[receptor antagonist|antagonist]] in breast tissue it acts as [[partial agonist]] on the [[endometrium]] and has been linked to [[endometrial cancer]] in some women. Therefore endometrial changes, including cancer, are among tamoxifen's side effects.<ref name="Grilli_2006">{{cite journal |author=Grilli S|title=Tamoxifen (TAM): the dispute goes on|journal= Ann Ist Super Sanita |volume= 42 |issue= 2 |pages= 170–3 |year= 2006 | doi = |pmid= 17033137 | url = http://www.iss.it/publ/anna/2006/2/422170.pdf}}</ref> The risk, however, is minute.

The [[American Cancer Society]] lists tamoxifen as a known carcinogen, stating that it increases the risk of some types of uterine cancer while lowering the risk of breast cancer recurrence.<ref name="ACS">{{cite web | url = http://www.cancer.org/docroot/PED/content/PED_1_3x_Known_and_Probable_Carcinogens.asp?sitearea=PED | title = Known and Probable Carcinogens | accessdate = 2008-03-21 | author = | authorlink = | coauthors = | date = 2006-02-03 | format = | work = | publisher = American Cancer Society | pages = | language = | archiveurl = | archivedate = | quote = }}</ref> The ACS states that its use should not be avoided in cases where the risk of breast cancer recurrence without the drug is higher than the risk of developing uterine cancer with the drug.

=== Cardiovascular and metabolic ===

Tamoxifen treatment of postmenopausal women is associated with beneficial effects on serum lipid profiles. However, long-term data from clinical trials have failed to demonstrate a cardioprotective effect.<ref name="pmid16230014">{{cite journal | author = Esteva FJ, Hortobagyi GN | title = Comparative assessment of lipid effects of endocrine therapy for breast cancer: implications for cardiovascular disease prevention in postmenopausal women | journal = Breast (Edinburgh, Scotland) | volume = 15 | issue = 3 | pages = 301–12 | year = 2006 | month = June | pmid = 16230014 | doi = 10.1016/j.breast.2005.08.033 | url = | issn = }}</ref> For some women, tamoxifen can cause a rapid increase in [[triglyceride]] concentration in the blood.{{Citation needed|date=April 2009}} In addition there is an increased risk of [[thromboembolism]] especially during and immediately after major surgery or periods of immobility.<ref name="pmid15699284">{{cite journal |author=Decensi A, Maisonneuve P, Rotmensz N, Bettega D, Costa A, Sacchini V, Salvioni A, Travaglini R, Oliviero P, D'Aiuto G, Gulisano M, Gucciardo G, del Turco MR, Pizzichetta MA, Conforti S, Bonanni B, Boyle P, Veronesi U |title=Effect of tamoxifen on venous thromboembolic events in a breast cancer prevention trial |journal=Circulation |volume=111 |issue=5 |pages=650–6 |year=2005 |pmid=15699284 |doi=10.1161/01.CIR.0000154545.84124.AC}}</ref> Tamoxifen is also a cause of [[fatty liver]], otherwise known as steatorrhoeic hepatosis or steatosis hepatis.<ref name="pmid17181445">{{cite journal |author=Khalid A Osman; Meissa M Osman; Mohamed H Ahmed |title=Tamoxifen-induced non-alcoholic steatohepatitis: where are we now and where are we going? |journal=Expert opinion on drug safety |volume=6 |issue=1 |pages=1–4 |year=2007 |pmid=17181445 |doi=10.1517/14740338.6.1.1}}</ref>

=== Central nervous system ===

Tamoxifen treated breast cancer patients show evidence of reduced [[cognition]]<ref name="pmid11194452">{{cite journal | author = Paganini-Hill A, Clark LJ | title = Preliminary assessment of cognitive function in breast cancer patients treated with tamoxifen | journal = Breast Cancer Research and Treatment | volume = 64 | issue = 2 | pages = 165–76 | year = 2000 | month = November | pmid = 11194452 | doi = 10.1023/A:1006426132338 | url = | issn = }}</ref> and [[semantic memory]] scores.<ref name="pmid14741674">{{cite journal | author = Eberling JL, Wu C, Tong-Turnbeaugh R, Jagust WJ | title = Estrogen- and tamoxifen-associated effects on brain structure and function | journal = NeuroImage | volume = 21 | issue = 1 | pages = 364–71 | year = 2004 | month = January | pmid = 14741674 | doi = 10.1016/j.neuroimage.2003.08.037 | url = | issn = }}</ref> However memory impairment in patients treated with tamoxifen was less severe compared with those treated with [[anastrozole]] (an [[aromatase inhibitor]]).<ref name="pmid17898668">{{cite journal | author = Bender CM, Sereika SM, Brufsky AM, Ryan CM, Vogel VG, Rastogi P, Cohen SM, Casillo FE, Berga SL | title = Memory impairments with adjuvant anastrozole versus tamoxifen in women with early-stage breast cancer | journal = Menopause (New York, N.Y.) | volume = 14 | issue = 6 | pages = 995–8 | year = 2007 | pmid = 17898668 | doi = 10.1097/gme.0b013e318148b28b | url = | issn = }}</ref>

A significant number of tamoxifen treated breast cancer patients experience a reduction of [[libido]].<ref name="pmid10334535">{{cite journal | author = Mortimer JE, Boucher L, Baty J, Knapp DL, Ryan E, Rowland JH | title = Effect of tamoxifen on sexual functioning in patients with breast cancer | journal = J. Clin. Oncol. | volume = 17 | issue = 5 | pages = 1488–92 | year = 1999 | pmid = 10334535 | doi = | issn = | url = http://jco.ascopubs.org/cgi/content/abstract/17/5/1488 | format = abstract}}</ref><ref name="pmid16944295">{{cite journal | author = Cella D, Fallowfield L, Barker P, Cuzick J, Locker G, Howell A | title = Quality of life of post-menopausal women in the ATAC ("Arimidex", tamoxifen, alone or in combination) trial after completion of 5 years' adjuvant treatment for early breast cancer | journal = Breast Cancer Res. Treat. | volume = 100 | issue = 3 | pages = 273–84 | year = 2006 | pmid = 16944295 | doi = 10.1007/s10549-006-9260-6 }}</ref>

=== Pre-mature growth plate fusion ===

While tamoxifen has been shown to antagonize the actions of estrogen in tissue's such as the breast, it's effects in other tissues such as bones has not been documented fully. There have been studies done in mice showing tamoxifen mimic the effects of estrogen on bone metabolism and skeletal growth. Thus increasing the possibility of pre-mature bone fusion. This effect would be less of a concern in adults who have stopped growing.<ref name="pmid18348701">{{cite journal | author = Karimian E, Chagin AS, Gjerde J, Heino T, Lien EA, Ohlsson C, Sävendahl L | title = Tamoxifen impairs both longitudinal and cortical bone growth in young male rats | journal = J. Bone Miner. Res. | volume = 23 | issue = 8 | pages = 1267–77 | year = 2008 | month = August | pmid = 18348701 | doi = 10.1359/jbmr.080319 | url = | issn = }}</ref>

== Pharmacogenetics ==

Patients with variant forms of the gene [[CYP2D6]] (also called simply 2D6) may not receive full benefit from tamoxifen because of too slow metabolism of the tamoxifen prodrug into its active metabolite 4-hydroxytamoxifen.<ref name="Goetz_2005">{{cite journal |author=Goetz MP, Rae JM, Suman VJ, Safgren SL, Ames MM, Visscher DW, Reynolds C, Couch FJ, Lingle WL, Flockhart DA, Desta Z, Perez EA, Ingle JN |title=Pharmacogenetics of tamoxifen biotransformation is associated with clinical outcomes of efficacy and hot flashes|journal= J Clin Oncol |volume= 23 |issue= 36 |pages= 9312–8 |year= 2005 | doi = 10.1200/JCO.2005.03.3266 |pmid= 16361630 }}</ref><ref name="Beverage_2007">{{cite journal |author=Beverage JN, Sissung TM, Sion AM, Danesi R, Figg WD |title=CYP2D6 polymorphisms and the impact on tamoxifen therapy|journal= J Pharm Sci |volume= 96 |issue= 9 |pages= Epub ahead of print |year= 2007 | doi = 10.1002/jps.20892 |pmid= 17518364 }}</ref> On Oct 18, 2006 the Subcommittee for Clinical Pharmacology recommended relabeling tamoxifen to include information about this gene in the package insert.<ref>[http://talk.dnadirect.com/2006/10/19/genetic-test-for-response-to-tamoxifen/ Information about CYP2D6 and tamoxifen from DNADirect's website]</ref>

Certain [[CYP2D6]] variations in breast cancer patients leads to a worse clinical outcome for tamoxifen treatment.<ref name="pmid19809024">{{cite journal | author = Schroth W, Goetz MP, Hamann U, Fasching PA, Schmidt M, Winter S, Fritz P, Simon W, Suman VJ, Ames MM, Safgren SL, Kuffel MJ, Ulmer HU, Boländer J, Strick R, Beckmann MW, Koelbl H, Weinshilboum RM, Ingle JN, Eichelbaum M, Schwab M, Brauch H | title = Association between CYP2D6 polymorphisms and outcomes among women with early stage breast cancer treated with tamoxifen | journal = JAMA | volume = 302 | issue = 13 | pages = 1429–36 | year = 2009 | month = October | pmid = 19809024 | doi = 10.1001/jama.2009.1420 | url = | issn = }}</ref> [[Genotyping]] therefore has the potential for identification of women who have these CYP2D6 phenotypes and for whom the use of tamoxifen is associated with poor outcomes.

Recent studies suggest that taking selective serotonin reuptake inhibitor (SSRI) antidepressants such as Paxil, Prozac, etc., can decrease the effectiveness of tamoxifen, because these drugs compete for the CYP2D6 enzyme which is needed to metabolize tamoxifen into the active form endoxifen.<ref name="Jin_2005">{{cite journal |author=Jin Y, Desta Z, Stearns V, Ward B, Ho H, Lee KH, Skaar T, Storniolo AM, Li L, Araba A, Blanchard R, Nguyen A, Ullmer L, Hayden J, Lemler S, Weinshilboum RM, Rae JM, Hayes DF, Flockhart DA |title=CYP2D6 genotype, antidepressant use, and tamoxifen metabolism during adjuvant breast cancer treatment|journal= J Natl Cancer Inst |volume= 97 |issue= 1 |pages= 30–9 |year= 2005 | doi = 10.1093/jnci/dji005 |pmid= 15632378}}</ref> A U.S study presented at the American Society of Clinical Oncology's annual meeting in 2009 found that after two years, 7.5 percent of women who took only tamoxifen had a recurrence, compared with 16 percent who took Paxil, Prozac, or Zoloft—drugs considered to be the most potent CYP2D6 inhibitors. That difference translates to a 120 percent increase in the risk of breast cancer recurrence. Patients taking the so-called weaker antidepressants, Celexa (citalopram), Lexapro (escitalopram), and Luvox (fluvoxamine), did not have an increased risk of recurrence.<ref>{{cite news |author=Staff Reports|title= ASCO Updates: Antidepressants Reduce the Effectiveness of Tamoxifen. |date=Summer, 2009 |publisher=CURE (Cancer Updates, Research and Education) |url=http://www.curetoday.com/index.cfm/fuseaction/article.show/id/2/article_id/1152}}</ref>

Recent research has shown that 7-10% of women with breast cancer may not receive the full medical benefit from taking tamoxifen due to their unique genetic make-up.DNA Drug Safety Testing can examine DNA variations in the CYP2D6 and other important drug processing pathways. More than 20% of all clinically used medications are metabolized by CYP2D6 and knowing the CYP2D6 status of a person can help the doctor with the future selection of medications.<ref>[http://www.tamoxitest.com/what_is_tamoxitest.html Information about Tamoxitest and how DNA testing can help in the selection of the best treatment methodology from Genelex's website]</ref>

== Market ==

Global sales of tamoxifen in 2001 were $1,024 million.<ref name="urlCancer the generic impact">{{cite web | url = http://www.bioportfolio.com/news/datamonitor_16.htm | title = Cancer the generic impact | author = | authorlink = | coauthors = | date = | work = | publisher = BioPortfolio Limited | pages = | language = | archiveurl = | archivedate = | quote = | accessdate = 2008-11-14}}</ref>
Since the expiration of the patent in 2002, it is now widely available as a [[generic drug]] around the world. Barr Labs Inc had challenged the patent (which in 1992 was ruled unenforcable) but later came to an agreement with Zeneca to licence the patent and sell tamoxifen at close to Zeneca's price.<ref name="urlPrescription Access Litigation (PAL) Project ">{{cite web | url = http://www.prescriptionaccess.org/lawsuitssettlements/past_lawsuits?id=0029 | title = Tamoxifen | author = | authorlink = | coauthors = | date = | format = | work = Lawsuits & Settlements | publisher = Prescription Access Litigation | pages = | language = | archiveurl = | archivedate = | quote = | accessdate = 2008-11-14}}</ref>
As of 2004, tamoxifen was the world's largest selling hormonal drug for the treatment of breast cancer.<ref name="urlwww.astrazeneca.se">{{cite web | url =http://www.astrazeneca.com/_mshost3690701/content/resources/media/investors/2004-abr-brent-vose-oncology.pdf | title = AstraZenecain Cancer: Slide #15: | author = Vose B | authorlink = | coauthors = | date = | format = | work = AstraZeneca Annual Business Review | publisher = www.astrazeneca.com| pages = | language = | archiveurl = | archivedate = | quote = 2004 tamoxifen market share: 70% Source: IMS HEALTH, IMS MIDAS Monthly. July 2004. Aromatase Inhibitors + Tamoxifen | accessdate = 2009-03-28}}</ref>

In the US, 20 mg tamoxifen tablets cost under $20 per month in quantity.<ref>[http://www.drugstore.com/pharmacy/prices/drugprice.asp?ndc=00093078256&trx=1Z5006 Drugstore.com accessed on 21 August 2009]</ref> In the UK, the NHS pays £1.90 a month (patients receive them either free or for the standard prescription charge of £7.10 in England, £4 in Scotland<ref>http://www.scotland.gov.uk/News/Releases/2007/12/05141211</ref> and free in Wales). Other countries report similar prices.{{Citation needed|date=August 2009}}

== Discovery ==

In the late 1950s, pharmaceutical companies were actively researching a newly discovered class of anti-estrogen compounds in the hope of developing a morning-after contraceptive pill.
[[Arthur L Walpole]] was a reproductive [[endocrinologist]] who led such a team at the [[Alderley Park]] research laboratories of [[ICI Pharmaceuticals]]. It was there in 1962 that Dora Richardson first synthesised tamoxifen, known then as ICI-46,474.<ref name="isbn0-471-89979-8">{{cite book | author = Sneader, Walter | title = Drug discovery: a history | publisher = Wiley | location = New York | year = 2005 | isbn = 0-471-89979-8 | oclc = | doi = | page = 472 pages }}</ref>
Walpole and his colleagues filed a UK patent covering this compound in 1962, but patent protection on this compound was repeatedly denied in the US until the 1980s.<ref name="Jordan_2003">{{cite journal | author = Jordan VC | title = Tamoxifen: a most unlikely pioneering medicine | journal = Nature reviews. Drug discovery | volume = 2 | issue = 3 | pages = 205–13 | year = 2003 | pmid = 12612646 | doi = 10.1038/nrd1031 }}</ref> Tamoxifen did eventually receive marketing approval as a fertility treatment, but the class of compounds never proved useful in human contraception. A link between estrogen and breast cancer had been known for many years, but cancer treatments were not a corporate priority at the time, and Walpole's personal interests were important in keeping support for the compound alive in the face of this and the lack of patent protection.<ref name="Jordan_2006"/>

The first clinical study took place at the [[Christie Hospital]] in 1971, and showed a convincing effect in advanced breast cancer,<ref name="Cole_1971">{{cite journal | author = Cole MP, Jones CT, Todd ID | title = A new anti-estrogenic agent in late breast cancer. An early clinical appraisal of ICI46474 | journal = Br. J. Cancer | volume = 25 | issue = 2 | pages = 270–5 | year = 1971 | pmid = 5115829 | doi = | issn = }}</ref> but nevertheless ICI's development programme came close to termination when it was reviewed in 1972. It appears to have been Walpole again who convinced the company to market tamoxifen for late stage breast cancer in 1973.<ref name="Jordan_2003"/> He was also instrumental in funding [[V. Craig Jordan]] to work on tamoxifen. Approval in the US followed in 1977, but the drug was competing against other hormonal agents in a relatively small marketplace and was not at this stage either clinically or financially remarkable.

1980 saw the publication of the first trial to show that tamoxifen given in addition to chemotherapy improved survival for patients with early breast cancer.<ref name="Baum_2003">{{cite journal | author = Baum M, Brinkley DM, Dossett JA, McPherson K, Patterson JS, Rubens RD, Smiddy FG, Stoll BA, Wilson A, Lea JC, Richards D, Ellis SH | title = Improved survival among patients treated with adjuvant tamoxifen after mastectomy for early breast cancer | journal = Lancet | volume = 2 | issue = 8347 | pages = 450 | year = 1983 | pmid = 6135926 | doi = 10.1016/S0140-6736(83)90406-3 }}</ref> In advanced disease, tamoxifen is now only recognised as effective in [[estrogen receptor]] positive (ER+) patients, but the early trials did not select ER+ patients, and by the mid 1980s the clinical trial picture was not showing a major advantage for tamoxifen.<ref name="FURR_1984">{{cite journal | author = Furr BJ, Jordan VC | title = The pharmacology and clinical uses of tamoxifen | journal = Pharmacol. Ther. | volume = 25 | issue = 2 | pages = 127–205 | year = 1984 | pmid = 6438654 | doi = 10.1016/0163-7258(84)90043-3 }}</ref> Nevertheless, tamoxifen had a relatively mild side-effect profile, and a number of large trials continued.
It was not until 1998 that the meta-analysis of the Oxford based Early Breast Cancer Trialists' Collaborative Group showed definitively that tamoxifen saved lives in early breast cancer.<ref name="pmid9605801">{{cite journal | author = Early Breast Cancer Trialists' Collaborative Group | title = Tamoxifen for early breast cancer: an overview of the randomised trials | journal = Lancet | volume = 351 | issue = 9114 | pages = 1451–67 | year = 1998 | pmid = 9605801 | doi = 10.1016/S0140-6736(97)11423-4 }}</ref>

== References ==
{{Reflist|2}}

== External links==
* [http://openwetware.org/wiki/Tamoxifen Tamoxifen on OpenWetWare], a life scientist wiki

{{Sex hormones}}

[[Category:Selective estrogen receptor modulators]]
[[Category:Chemopreventive agents]]
[[Category:AstraZeneca]]
[[Category:Cancer treatments]]
[[Category:IARC Group 1 carcinogens]]
[[Category:Treatment of bipolar disorder]]

[[de:Tamoxifen]]
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[[pl:Tamoksyfen]]
[[pt:Tamoxifeno]]

Ishikawa reagent

2009-12-05T12:15:32Z

Su-no-G: +ja

'''Ishikawa's reagent''' is a fluorinating reagent used in organic chemistry. It is used to convert [[alcohols]] into alkyl fluorides and [[carboxylic acids]] into [[acyl fluoride]]s. The reagent consists of a mixture of diethyl-(1,1,2,3,3-hexafluoropropyl)amine and diethyl-(''E'')-pentafluoropropenylamine in varying proportions. The active species is the hexafluoropropylamine; any [[enamine]] is converted into this by the [[hydrogen fluoride]] byproduct as the reaction proceeds.

Ishikawa's reagent is a popular alternative to the [[DAST]] reagent, since it is shelf-stable and easily prepared from inexpensive and innocuous reagents. It is an improvement on ''Yarovenko's reagent'', the adduct of [[chlorotrifluoroethylene]] and [[diethylamine]], which must be prepared in a sealed vessel and once prepared keeps only for a few days, even in the refrigerator.

The reagent is mostly used to convert primary alcohols to alkyl fluorides under mild conditions with high yield. However, secondary and tertiary alcohols give a substantial amount of alkenes and ethers as side products.

==Synthesis==
The compound is prepared by adding [[hexafluoropropene]] to a solution of [[diethylamine]] in [[diethyl ether|ether]] at 0 °C and distilling the product ''in vacuo''. The amount of enamine in the product depends on temperature control during the reaction – the higher the temperature the more enamine.

==References==
Akio Takaoka, Hiroshi Iwakiri, Nobuo Ishikawa, Bull. Chem. Soc. Jpn 1979, 52, 3377-80

[[Category:Organofluorides]]
[[Category:Reagents for organic chemistry]]
[[ja:石川試薬]]

2,3-Dichloro-5,6-dicyano-1,4-benzoquinone

2009-12-05T11:26:30Z

Su-no-G: +ja

:''"DDQ" redirects here. [[RTQ|DDQ]] is also the former callsign of a TV station in Toowoomba, Australia.''
{{Chembox
| Reference=<ref>[http://www.sigmaaldrich.com/catalog/ProductDetail.do?lang=en&N4=D60400|ALDRICH&N5=SEARCH_CONCAT_PNO|BRAND_KEY&F=SPEC 2,3-Dichloro-5,6-dicyano-''p''-benzoquinone] at [[Sigma-Aldrich]]</ref>
| ImageFile = 2,3-dicyano-5,6-dichloroparabenzoquinone.svg
| ImageSize = 120px
| IUPACName =
| OtherNames = 2,3-Dichloro-5,6-dicyano-''p''-benzoquinone; 4,5-Dichloro-3,6-dioxo-1,4-cyclohexadiene-1,2-dicarbonitrile
| Section1 = {{Chembox Identifiers
| Abbreviations = DDQ
| CASNo = 84-58-2
| PubChem =
| RTECS = GU4825000
| EINECS = 201-542-2
| SMILES = }}
| Section2 = {{Chembox Properties
| C=8|Cl=2|N=2|O=2
| Appearance =
| Density =
| MeltingPt = 210-215 °C (dec.)
| BoilingPt =
| Solubility = }}
| Section3 = {{Chembox Hazards
| MainHazards =
| FlashPt =
| Autoignition =
| RPhrases = {{R25}} {{R29}}
| SPhrases = {{S22}} {{S24/25}} {{S37}} {{S45}}
}}
}}

'''2,3-Dichloro-5,6-dicyano-1,4-benzoquinone''' (DDQ) is a [[reagent]] used in [[organic chemistry]] as a mild [[redox|oxidizing agent]].

==References==
{{reflist}}

{{DEFAULTSORT:Dichloro-5,6-dicyano-1,4-benzoquinone, 2,3-}}
[[Category:reagents for organic chemistry]]
[[Category:Nitriles]]
[[Category:Quinones]]
[[Category:Organochlorides]]

{{organic-compound-stub}}

[[ja:2,3-ジクロロ-5,6-ジシアノ-p-ベンゾキノン]]

Fukuyama reduction

2009-11-30T14:08:59Z

Su-no-G: +ja

The '''Fukuyama reduction''' is an [[organic reaction]] and an [[organic reduction]] in which a [[thioester]] is reduced to an [[aldehyde]] by a [[silyl hydride]] in presence of a [[catalytic]] amount of [[palladium]]. This reaction was invented in 1990 by [[Tohru Fukuyama]] <ref>''Facile reduction of ethyl thiol esters to aldehydes: application to a total synthesis of (+)-neothramycin A methyl ether'' Tohru Fukuyama, Shao Cheng Lin, Leping Li [[J. Am. Chem. Soc.]], 1990, 112 (19), pp 7050–7051 {{DOI|10.1021/ja00175a043}}</ref> . In the original scope of the reaction the silyl hydride was [[triethylsilyl hydride]] and the catalyst [[palladium on carbon]]:

:[[File:Fukuyama reduction.svg|The Fukuyama reduction]]

Fukuyama reductions are used for the conversion of [[carboxylic acid]]s (as thioester precursor) to aldehydes which is considered a difficult procedure because of the ease of secondary reduction to an [[alcohol]].

==Reaction mechanism==
The basic [[reaction mechanism]] for this reaction takes place as a [[catalytic cycle]]:
* [[Oxidative addition]]:
:R-C(O)-SR + pd(0) → RC(O)-Pd(II)-SR
* [[Transmetallation]]:
:RC(O)-Pd(II)-SR + R3SiH → RC(O)-Pd(II)-H + R3Si-SR
* [[Reductive elimination]]:
: RC(O)-Pd(II)-H → RC(O)-H + Pd(0)

==Scope==
In a variation of the Fukuyama reduction the core [[BODIPY]] molecule has been synthesized from the SMe-substituted derivative <ref>''The Smallest and One of the Brightest. Efficient Preparation and Optical Description of the Parent Borondipyrromethene System.'' I. J. Arroyo, R. Hu, G. Merino, B. Z. Tang, E. Peña-Cabrera, [http://dx.doi.org/10.1021/jo901014w ''J. Org. Chem.'' '''2009, ASAP''']
</ref> <ref>Additional reagents [[Copper(I)-thiophene-2-carboxylate|CuTC]], [[Pd(dba)2]], [[trialkyl phosphine|tri(2-furyl)phosphine]] </ref>:

:[[File:BODIPY synthesis Arroyo 2009.svg|BODIPY synthesis Arroyo 2009]]

In the related [[Fukuyama coupling]] the hydride is replaced by a [[carbon nucleophile]].

==References==
{{reflist}}

[[Category:Organic reactions]]

[[es:Reducción de Fukuyama]]
[[ja:福山還元]]
[[zh:Fukuyama还原反应]]

Takai olefination

2009-11-30T14:04:21Z

Su-no-G: +ja

'''Takai olefination''' in [[organic chemistry]] describes the [[organic reaction]] of an [[aldehyde]] with a [[diorganochromium|diorganochromium compound]] to form an [[alkene]]. In the original 1986 publication <ref>''Simple and selective method for aldehydes (RCHO) -> (E)-haloalkenes (RCH:CHX) conversion by means of a haloform-chromous chloride system '' K. Takai, K. Nitta, K. Utimoto [[J. Am. Chem. Soc.]]; '''1986'''; 108(23); 7408-7410. {{DOI|10.1021/ja00283a046}}</ref> the aldehyde is [[benzaldehyde]] and the organochromium species is generated from [[iodoform]] or [[bromoform]] and an excess of [[chromium(II) chloride]]. The reaction product is a [[vinyl halide]]. The main selling point is the [[entgegen|E]]-configuration of the double bond. According to the principal investigator Kazuhiko Takai, existing alternatives such as the [[Wittig reaction]] only yield mixtures.

:[[Image:TakaiOlefination.svg|Takai olefination]]

In the [[reaction mechanism]] proposed by Takai, chromium(II) is oxidized to chromium(III) when replacing both halogen atoms. The geminal carbodianion complex thus formed reacts with the aldehyde in a 1,2-addition along one of the carbon to chromium bonds and in the next step both chromium bearing groups engage in an [[elimination reaction]]. In [[newman projection]] it can be seen how the [[steric bulk]]s of chromium groups and the steric bulks of the alkyl and halogen groups drive this reaction towards anti elimination <ref>Strategic Applications of Named Reactions in Organic Synthesis (Paperback) by Laszlo Kurti, Barbara Czako ISBN 0-12-429785-4 </ref>.

:[[Image:TakaiMechanism.svg|Takai mechanism]]

In a second publication the scope of the reaction was extended to diorganochromium intermediates bearing alkyl groups instead of halogens <ref>''(E)-Selective olefination of aldehydes by means of gem-dichromium reagents derived by reduction of gem-diiodoalkanes with chromium(II) chloride '' T. Okazoe, Kazuhiko Takai, K. Utimoto [[J. Am. Chem. Soc.]]; '''1987'''; 109(3); 951-953. {{DOI|10.1021/ja00237a081}}</ref>:

:[[Image:TakaiVariation.svg|Takai reaction 1987]]
==References==
{{Reflist}}

[[Category:Organic reactions]]
[[Category:Name reactions]]

[[de:Takai-Olefinierung]]
[[ja:高井オレフィン化反応]]
[[zh:Takai反应]]

Category:Terbium compounds

2009-11-17T05:12:39Z

Su-no-G: +ja

{{main|Terbium}}
{{Commons cat|Terbium compounds}}

[[Category:Chemical compounds by element]]
[[Category:Lanthanide compounds]]
[[Category:Terbium]]

[[de:Kategorie:Terbiumverbindung]]
[[ja:Category:テルビウムの化合物]]

Hering–Breuer reflex

2009-11-16T11:39:24Z

Su-no-G: +ja

{{histinfo|How did Hering and Breur discover the reflex?}}

The '''Hering-Breuer inflation reflex''', named for [[Josef Breuer]] and [[Ewald Hering]]<ref>{{WhoNamedIt|synd|3172}}</ref><ref>K. E. K. Hering. Die Selbststeuerung der Athmung durch den Nervus vagus. Sitzungsberichte der kaiserlichen Akademie der Wissenschaften. Mathematisch–naturwissenschaftliche Classe, Wien, 1868, 57 Band, II. Abtheilung: 672-677.</ref><ref>Josef Breuer. Die Selbststeuerung der Athmung durch den Nervus vagus. Sitzungsberichte der kaiserlichen Akademie der Wissenschaften. Mathematisch–naturwissenschaftliche Classe, Wien, 1868, 58 Band, II. Abtheilung: 909-937.</ref>, is a [[reflex]] triggered to prevent overinflation of the [[lungs]]. [[Pulmonary stretch receptors]] present in the smooth muscle of the airways respond to excessive stretching of the lung during large [[Inhalation|inspiration]]s.

Once activated, they send [[action potential]]s through large [[myelin]]ated fibers<ref name="West">{{cite book |author=West, John F. |title=Respiratory physiology: the essentials |publisher=Lippincott Williams & Wilkins |location=Hagerstown, MD |year=2005 |pages=127–8 |isbn=0-7817-5152-7 |oclc= |doi=}}</ref> of the paired [[vagus nerve]]s to the inspiratory area in the medulla and [[apneustic area ]] of the [[pons]]. In response, the inspiratory area is inhibited directly and the apneustic area is inhibited from activating the inspiratory area. This inhibits inspiration, allowing expiration to occur.<ref name="Sherwood">{{cite book |author=Sherwood, Lauralee |title=Human physiology: from cells to systems |publisher=Brooks/Cole |location=Pacific Grove, CA |year=2001 |pages= |chapter=Ch 13 |isbn=0534568262 |oclc= |doi=}}</ref><ref name="Tortora">{{cite book |author=Tortora, Gerard J. |title=Principals of Anatomy and Physiology |publisher=Wiley |location=Hoboken, NJ |year=2009 |page=909 |chapter=Ch 23 |isbn=9780470084717 |oclc= |doi=}}</ref>

The Hering-Breuer inflation reflex ought not be confused with the deflation reflex discovered by the same individuals, Hering and Breuer. The majority of this page discusses the ''inflation'' reflex; the deflation reflex is considered separately at the end.

==History==
Josef Breuer and Ewald Hering reported in 1868 that a maintained distention of the lungs of anesthetized animals decreased the frequency of the inspiratory effort or caused a transient apnea. The stimulus was therefore pulmonary inflation.

==Anatomy and physiology==
The neural circuit that controls the Hering-Breuer inflation reflex involves several regions of the [[central nervous system]], and both sensory and motor components of the vagus nerve.
Increased sensory activity of the pulmonary-stretch lung afferents (via the vagus nerve) results in inhibition of the central inspiratory drive and thus inhibition of inspiration and initiation of expiration. The lung afferents also send inhibitory projections to the cardiac vagal motor neurones (CVM) in the nucleus ambiguus (NA) and dorsal motor vagal nucleus (DMVN). The CVMs, which send motor fibers to the [[heart]] via the vagus nerve, are responsible for tonic inhibitory control of [[heart rate]]. Thus, an increase in pulmonary stretch receptor activity leads to inhibition of the CVMs and an elevation of heart rate (tachycardia). This is a normal occurrence in healthy individuals and is known as sinus arrhythmia.

==Rate and depth of breathing==
Early physiologists believed the reflex played a major role in establishing the rate and depth of breathing in humans.<ref name="West"/> While this may be true for most animals, it is not the case for most adult humans at rest.<ref name="West"/> However, the reflex may determine breathing rate and depth in newborns and in adult humans when [[Tidal volume#Measurement and values|tidal volume]] is more than 1 L, as when exercising.<ref name="West"/>

==Hering-Breuer deflation reflex==

The Hering-Breuer deflation reflex serves to shorten exhalation when the lung is deflated.<ref>http://www.lib.mcg.edu/edu/eshuphysio/program/section4/4ch6/s4ch6_15.htm</ref> It is initiated either by stimulation of stretch receptors or stimulation of propriocetors activated by lung deflation. Like the inflation reflex, impulses from these receptors travel afferently via the vagus. Unlike the inflation reflex, the afferents terminate on inspiratory centers rather than the pontine apneustic center. These reflexes appear to play a more minor role in humans than in non-human mammals.

==References==
{{reflist|2}}

==External links==
* {{GeorgiaPhysiology|4/4ch6/s4ch6_15}}
* {{eMedicineDictionary|Hering-Breuer+reflex}}

{{Respiratory physiology}}

[[Category:Respiratory physiology]]
[[Category:Reflexes]]

[[de:Hering-Breuer-Reflex]]
[[it:Riflesso di Hering-Breuer]]
[[ja:ヘーリング・ブロイウェル反射]]
[[pl:Odruch Heringa-Breuera]]

The Journal of Organic Chemistry

2009-11-11T15:11:09Z

Su-no-G: modifying ja

{{Infobox Journal
| cover = [[Image:joc_cover.jpg|150 px]]
| editor = C. Dale Poulter
| discipline = [[Chemistry]]
| language = English
| abbreviation = J. Org. Chem.
| website = http://pubs.acs.org/journals/joceah/
| publisher = [[American Chemical Society]]
| country = {{Flag|USA}}
| frequency = Bi-monthly
| history = 1936 to present
| impact = 3.952
| impact-year = 2008
| website = http://pubs.acs.org/journal/joceah
| RSS = http://pubs.acs.org/action/showFeed?ui=0&mi=qjmolc&ai=53h&jc=joceah&type=etoc&feed=rss
| CODEN = joceah
| ISSN = 0022-3263
| eISSN = 1520-6904
}}

The '''''Journal of Organic Chemistry''''' (abbreviated as ''J. Org. Chem.'' or ''JOC'') is a [[scientific journal]] for original contributions of fundamental research in [[organic chemistry|organic]] and [[bioorganic chemistry]]. It is published by the [[American Chemical Society]]. The [[impact factor]] of this journal is 3.959 (2007).<ref>Journal Citation Reports, 2007 </ref>

''JOC'' is currently indexed in: [[CAS]], [[SCOPUS]], [[EBSCOhost]], [[British Library]], [[PubMed]], [[Ovid]], [[Web of Science]], [[Gale Group]], [[Proquest]], [[CABI]] and SwetsWise.

The current Editor-in-Chief is C. Dale Poulter.<ref>[http://pubs.acs.org/page/joceah/profile.html Editor profile]</ref>

==References==
<references/>
{{Reflist}}

[[Category:ACS journals]]

{{chem-journal-stub}}

[[de:Journal of Organic Chemistry]]
[[es:Journal of Organic Chemistry]]
[[id:Journal of Organic Chemistry]]
[[ja:Journal of Organic Chemistry]]
[[pl:Journal of Organic Chemistry]]
[[zh:有机化学期刊]]

Etomidate

2009-11-03T08:17:46Z

Su-no-G: +ja

{{Refimprove|date=April 2007}}

{{drugbox | verifiedrevid = 309735310
|
| IUPAC_name = ethyl 3-[(1''R'')-1-phenylethyl]imidazole- 4-carboxylate
| image = Etomidat Structural Formulae.png
| image2 = Etomidate3d.png
| CASNo_Ref = {{cascite}}
| CAS_number = 33125-97-2
| ATC_prefix = N01
| ATC_suffix = AX07
| PubChem = 667484
| DrugBank = APRD00965
| C = 14 |H = 16 |N = 2 |O = 2
| molecular_weight = 244.289 [[Gram|g]]/[[Mole (unit)|mol]]
| protein_bound = 75%
| metabolism = [[Ester]] [[hydrolysis]]
| elimination_half-life = 75 [[Minutes|min]]
| excretion = [[Kidney|Renal]] (85%) and biliary (15%)
| pregnancy_category = D ([[United States|U.S.]])
| legal_UK = POM
| routes_of_administration = [[Intravenous therapy|Intravenous]]
}}

'''Etomidate''' is a short acting [[intravenous]] anaesthetic agent used for the induction of [[general anaesthesia]] and for [[sedation]]<ref name="pmid12023700">{{cite journal |author=Vinson DR, Bradbury DR |title=Etomidate for procedural sedation in emergency medicine |journal=Ann Emerg Med |volume=39 |issue=6 |pages=592–8 |year=2002 |month=June |pmid=12023700 |doi= |url=http://linkinghub.elsevier.com/retrieve/pii/S0196064402840033}}</ref> for short procedures such as reduction of dislocated joints and [[cardioversion]]. It was discovered at [[Janssen Pharmaceutica]] in [[1964]].

A new form of etomidate is being tested at Harvard University Medical School in animals; two advantages it offers are a lesser, more stable drop in blood pressure (most all general anesthetics will cause some drop in blood pressure, which is not problematic for young and healthy and fit patients but can be for the elderly or those with blood loss, shock, sepsis, arrhythmias, vascular disease, or hematological disorders or malignancies), and secondly less repression of adrenal activity. These are two potentially significant improvements over the previous version and other general anesthesia drugs, making this version better for seriously ill or injured patients.

==Drug class==
Etomidate, a hypnotic is a carboxylated [[imidazole]] derivative. Etomidate has [[anesthesia|anesthetic]] and [[amnesia|amnestic]] properties, but has no [[analgesia|analgesic]] properties.

==Uses==
Etomidate is commonly used in the emergency setting as part of a [[facilitated intubation]] to induce anesthesia or for [[conscious sedation]]. It is often used in this setting since it has a rapid onset of action and a low cardiovascular risk profile, and therefore is less likely to cause a significant drop in blood pressure than other induction agents.

In the operating room with a stable patient, anesthesia providers may choose an alternative induction agent, such as [[propofol]], [[thiopental]] or [[methohexital]]. (see Side effects below).

At the typical dose, anesthesia is induced for about 5–10 minutes even though the half-life of drug metabolism is approximately 75 minutes. This is because etomidate is redistributed from the plasma to other tissues.

==Dosage==
The anaesthetic induction dose for adult humans is 0.3 mg/kg intravenously, with a typical dose ranging from 20-40 mg. In common with all induction agents, etomidate causes loss of consciousness after one '''arm-brain circulation time'''. In very brief procedures such as cardioversion, a 10 mg dose may be used which may be repeated for effect.

DOSING: ADULTS — Anesthesia: I.V.: Initial: 0.2-0.6 mg/kg over 30-60 seconds for induction of anesthesia; maintenance: 5-20 mcg/kg/minute

==Pharmacology==
Etomidate is an agonist at [[GABAA receptor|GABAA]] [[Receptor (biochemistry)|receptors]]<ref>Vanlersberghe C, Camu F. Etomidate and other non-barbiturates. ''Handbook of Experimental Pharmacology''. 2008;(182):267-82. PMID 18175096</ref> containing β3 subunits.<ref>Drexler B, Jurd R, Rudolph U, Antkowiak B. Distinct actions of etomidate and propofol at beta3-containing gamma-aminobutyric acid type A receptors. ''Neuropharmacology''. 2009 Sep;57(4):446-55. PMID 19555700</ref>

==Metabolism==
Etomidate is highly protein bound in [[blood plasma]] and is metabolised by hepatic and plasma [[esterase]]s to inactive products. It exhibits a [[Exponential decay|bi-exponential decline]], with a redistribution [[half-life]] of 2–5 minutes and an elimination half-life of 68–75 minutes.

==Side effects==
The use of etomidate infusions for [[sedation]] of critically ill patients in [[intensive care unit]]s has been associated with increased mortality, which is due to suppression of [[steroid]] synthesis (both [[glucocorticoid]]s and [[mineralocorticoid]]s) in the [[adrenal cortex]]. Thus, etomidate contributes to [[critical illness–related corticosteroid insufficiency]]. This effect has been demonstrated after a single dose, and lasts about 24 hours. There is no evidence that a single induction dose of etomidate has any effect on morbidity or mortality. However, some sources advise giving a prophylactic dose of steroids (e.g. [[hydrocortisone]]) if etomidate is used.

Seizure-like activity is occasionally seen with anesthetic induction. In the absence of concurrent EEG monitoring, it is difficult to ascribe this to cortical activity. [[Myoclonic]] movement originating at the spinal cord level is often a likely mechanism. Excitatory phenomena, and epileptiform movements and [[EEG]] activity may be observed during induction. Etomidate consistently increases the amplitude of somatosensory [[evoked potentials]] (in contrast to most anaesthetic agents).

Etomidate in the propylene glycol formulation may produce [[Pain and nociception|pain]] on injection, a side effect which is less likely with the lipid formulation.

There is a 30-fold difference between the [[effective dose]] and the [[lethal dose]] of etomidate, making it an extremely safe agent.

Post operative vomiting is more common than with other induction agents.

==Formulation==
Etomidate is usually presented as a clear colourless solution for injection containing 2 mg/ml of etomidate in an aqueous solution of 35% [[propylene glycol]], although a [[lipid]] [[emulsion]] preparation (of equivalent strength) has also been introduced. Etomidate is presented as a [[racemic]] mixture, but only the D-[[isomer]] has pharmacological activity.

==Pharmacokinetics==

*Onset of action: 30-60 seconds
*Peak effect: 1 minute
*Duration: 3-5 minutes; terminated by redistribution
*Distribution: Vd: 2-4.5 L/kg
*Protein binding: 76%
*Metabolism: Hepatic and plasma esterases
*Half-life elimination: Terminal: 2.6 hours

==References==

Cotton, B. A., O. D. Guillamondegui, S. B. Fleming, R. O. Carpenter, S. H. Patel, J. A. Morris, Jr. and P. G. Arbogast (2008). "Increased risk of adrenal insufficiency following etomidate exposure in critically injured patients." Arch Surg 143(1): 62-7; discussion 67.

den Brinker, M., A. C. Hokken-Koelega, J. A. Hazelzet, F. H. de Jong, W. C. Hop and K. F. Joosten (2008). "One single dose of etomidate negatively influences adrenocortical performance for at least 24h in children with meningococcal sepsis." Intensive Care Med 34(1): 163-8.

Hildreth, A. N., V. A. Mejia, R. A. Maxwell, P. W. Smith, B. W. Dart and D. E. Barker (2008). "Adrenal suppression following a single dose of etomidate for rapid sequence induction: a prospective randomized study." J Trauma 65(3): 573-9.

Marik, P. E., S. M. Pastores, D. Annane, G. U. Meduri, C. L. Sprung, W. Arlt, D. Keh, J. Briegel, A. Beishuizen, I. Dimopoulou, S. Tsagarakis, M. Singer, G. P. Chrousos, G. Zaloga, F. Bokhari and M. Vogeser (2008). "Recommendations for the diagnosis and management of corticosteroid insufficiency in critically ill adult patients: consensus statements from an international task force by the American College of Critical Care Medicine." Crit Care Med 36(6): 1937-49.

Mullins, M. E. and D. L. Theodoro (2008). "Lack of evidence for adrenal insufficiency after single-dose etomidate." Arch Surg 143(8): 808-9; author reply 809.

Sacchetti, A. (2008). "Etomidate: not worth the risk in septic patients." Ann Emerg Med 52(1): 14-6.

Sprung, C. L., D. Annane, D. Keh, R. Moreno, M. Singer, K. Freivogel, Y. G. Weiss, J. Benbenishty, A. Kalenka, H. Forst, P. F. Laterre, K. Reinhart, B. H. Cuthbertson, D. Payen and J. Briegel (2008). "Hydrocortisone therapy for patients with septic shock." N Engl J Med 358(2): 111-24.

Tekwani, K., H. Watts, C. Chan, K. Rzechula, S. Nanini and E. Kulstad (2008). "The effect of single-bolus etomidate on septic patient mortality: a retrospective review." West J of Emerg Med 9(4): 195-200.

Tekwani, K. L., H. F. Watts, K. H. Rzechula, R. T. Sweis and E. B. Kulstad (2009). "A prospective observational study of the effect of etomidate on septic patient mortality and length of stay." Acad Emerg Med 16(1): 11-4.

Vinclair, M., C. Broux, P. Faure, J. Brun, C. Genty, C. Jacquot, O. Chabre and J. F. Payen (2008). "Duration of adrenal inhibition following a single dose of etomidate in critically ill patients." Intensive Care Med 34(4): 714-9.

Walls, R. M. and M. F. Murphy (2008). "Clinical controversies: etomidate as an induction agent for endotracheal intubation in patients with sepsis: continue to use etomidate for intubation of patients with septic shock." Ann Emerg Med 52(1): 13-4.

{{reflist}}

{{General anesthetics}}
{{GABAergics}}

[[Category:General anesthetics]]
[[Category:Imidazoles]]

[[de:Etomidat]]
[[es:Etomidato]]
[[fr:Étomidate]]
[[it:Etomidate]]
[[ja:エトミデート]]
[[nl:Etomidaat]]
[[pl:Etomidat]]
[[pt:Etomidato]]
[[ru:Этомидат]]

Cobalt fluoride

2009-11-03T01:15:18Z

Su-no-G: +ja

'''Cobalt fluoride''' may refer to:

* [[Cobalt trifluoride]] (cobalt(III) fluoride), CoF3
* [[Cobalt(II) fluoride]] (cobalt difluoride), CoF2

{{disambig}}

[[ja:フッ化コバルト]]

Meisenheimer complex

2009-10-23T14:12:21Z

Su-no-G: +ja

A '''Meisenheimer complex''' or '''Jackson-Meisenheimer''' complex in [[organic chemistry]] is a 1:1 reaction [[adduct]] between an [[arene compound|arene]] carrying [[electron withdrawing group]]s and [[nucleophile]]. These complexes are found as [[reactive intermediate]]s in [[nucleophilic aromatic substitution]] but stable and isolated Meisenheimer salts are also known.<ref>{{cite journal | title = Some aspects of anionic σ-complexes | author = G. A. Artamkina, M. P. Egorov, I. P. Beletskaya | journal = [[Chem. Rev.]] | year = 1982 | volume = 82 | issue = 4 | pages = 427–459 | doi = 10.1021/cr00050a004}}</ref><ref>{{cite journal | title = Rate and equilibrium studies in Jackson-Meisenheimer complexes | author = Francois Terrier | journal = [[Chem. Rev.]] | year = 1982 | volume = 82 | issue = 2 | pages = 77–152 | doi = 10.1021/cr00048a001}}</ref><ref>{{GoldBookRef | title = Meisenheimer complex | file = M03819}}</ref>

==Background==
The early development of this type of complex takes place around the turn of the 19th century. In 1886 Janovski observed an intense violet color when he mixed meta-dinitrobenzene with an alcoholic solution of alkali. In 1895 [[Cornelis Adriaan Lobry van Troostenburg de Bruyn|Lobry de Bruyn]] investigated a red substance formed in the reaction of [[trinitrobenzene]] with [[potassium hydroxide]] in [[methanol]]. In 1900 Jackson and Gazzolo reacted trinitroanisole with sodium [[methoxide]] and proposed a [[quinoid]] structure for the reaction product.

:[[Image:MeisenheimerComplex.png|500px|Scheme 1. The Meisenheimer complex]]

In 1902 [[Jakob Meisenheimer]] <ref>{{cite journal
| title = Ueber Reactionen aromatischer Nitrokörper
| author = [[Jakob Meisenheimer]]
| journal = [[Annalen der Chemie|Justus Liebigs Annalen der Chemie]]
| volume = 323
| issue = 2
| year = 1902
| pages = 205–246
| doi = 10.1002/jlac.19023230205}}</ref> observed that by acidifying their reaction product, the starting material was recovered.

With three electron withdrawing groups, the negative charge in the complex is located at one of the nitro groups according to the quinoid model. When less electron poor arenes this charge is delocalized over the entire ring (structure to the right in ''scheme 1'').

In one study<ref>{{cite journal | title = Evidence for Carbon-Carbon Meisenheimer-Wheland Complexes between Superelectrophilic and Supernucleophilic Carbon Reagents | author = Carla Boga, Erminia Del Vecchio, Luciano Forlani, Andrea Mazzanti, Paolo E. Todesco | journal = [[Angewandte Chemie]] | volume = 117 | issue = 21 | pages = 3349–3353 | year = 2005 | doi = 10.1002/ange.200500238}}</ref> a Meisenheimer arene (4,6-Dinitrobenzofuroxan) was allowed to react with a strongly electron-releasing arene (1,3,5-tris(N-pyrrolidinyl)benzene) forming a [[zwitterion]]ic Meisenheimer - Wheland complex. The [[Wheland intermediate]] is its opposite number and the [[reactive intermediate]] in [[electrophilic aromatic substitution]].

:[[Image:MeisenHeimerWhelandComplex.png|380px|Scheme 2 Meisenheimer -Wheland complex]]

The structure of this complex was confirmed by [[NMR spectroscopy]].

==Janovski reaction==

The '''Janovski reaction''' is the reaction of 1,3-[[dinitrobenzene]] with an [[enol]]izable [[ketone]] to the Meisenheimer adduct.

==Zimmermann reaction==
In the '''Zimmermann reaction''' the Janovski adduct is oxidized with excess base to a strongly colored enolate with subsequent reduction of the dinitro compound to the aromatic nitro amine.<ref>{{cite journal | title = Electronic structure of [n.1.1]propellanes. PE (photoelectron) spectroscopic investigations | author = Rolf Gleiter, Karl Heinz Pfeifer, Guenter Szeimies, Johannes Belzner, and Klaus Lehne |journal = [[J. Org. Chem.]] | year = 1990 | volume = 55 | issue = 2 | pages = 633–636 | doi = 10.1021/jo00289a044}}</ref> This reaction is the basis of the '''Zimmermann test''' used for the detection of [[Ketosteroids]].

[[Image:ZimmermannReaction.png|400px|Scheme 3. Zimmermann reaction]]

==References==
<references/>

[[Category:Reactive intermediates]]
[[Category:salts]]
[[ja:マイゼンハイマー錯体]]

Terbium(III) oxide

2009-10-21T14:01:22Z

Su-no-G: +ja

{{chembox
| ImageFile = Tl2O3structure.jpg
| ImageSize =
| IUPACName =
| OtherNames = terbium trioxide, terbia
| Section1 = {{Chembox Identifiers
| Abbreviations =
| CASNo = 12036-41-8
| EINECS = 234-849-5
| PubChem = 159410
| SMILES =
| InChI = 1/3O.2Tb/q3*-2;2*+3
| RTECS =
| MeSHName =
| ChEBI =
| KEGG =
| ATCCode_prefix =
| ATCCode_suffix =
| ATC_Supplemental =}}
| Section2 = {{Chembox Properties
| Tb = 2 | O = 3
| Formula =
| MolarMass =
| Appearance = white crystals
| Density =
| MeltingPtC = 2410
| Melting_notes =
| BoilingPt =
| Boiling_notes =
| Solubility =
| SolubleOther =
| MagneticSusceptibility = 0.07834 cm3/mol
| Solvent =
| pKa =
| pKb =
}}
| Section3 = {{Chembox Structure
| CrystalStruct = [[Cubic]], [[Pearson symbol|cI80]]
| SpaceGroup = Ia-3, No. 206<ref>{{cite journal| journal = J. Phys. F| year = 1973 | volume = 3 | page = 1-5| title = The observation of face centred cubic Gd, Tb, Dy, Ho, Er and Tm in the form of thin films and their oxidation|doi=10.1088/0305-4608/3/1/009| author = Curzon A.E., Chlebek H.G.}}</ref>
}}
| Section7 = {{Chembox Hazards
| EUClass = not listed
| EUIndex =
| MainHazards =
| NFPA-H =
| NFPA-F =
| NFPA-R =
| NFPA-O =
| RPhrases =
| SPhrases =
| RSPhrases =
| FlashPt =
| Autoignition =
| ExploLimits =
| PEL = }}
}}
'''Terbium(III) oxide''', also known as '''terbium sesquioxide''', is a [[sesquioxide]] of the rare earth metal [[terbium]], having [[chemical formula]] {{chem|Tb|2|O|3}}. It is a p-type [[semiconductor]],<ref>{{cite journal|journal=Solid State Ionics|volume=176|issue=39–40|month=December | year=2005|pages=2957–2961|doi=10.1016/j.ssi.2005.09.030|publisher=Elsevier B.V.|title=Proton conductivity of Ca-doped {{chem|Tb|2|O|3}}|author=Reidar Haugsrud, Yngve Larring, and Truls Norby}}</ref> and may be prepared by the reduction of [[Terbium(III,IV) oxide|{{chem|Tb|4|O|7}}]] in [[hydrogen]] at 1300°C for 24 hours.<ref>{{cite journal|journal=Journal of Applied Crystallography|volume=4|issue=5|month=October | year=1971|pages=399–400|doi=10.1107/S0021889871007295|title=Crystal data on C-type terbium sesquioxide ({{chem|Tb|2|O|3}})|author=G. J. McCarthy}}</ref>

==References==
{{reflist}}

{{Terbium compounds}}

[[Category:Oxides]]
[[Category:Terbium compounds]]
[[Category:Inorganic compound stubs]]

{{inorganic-compound-stub}}

[[de:Terbium(III)-oxid]]
[[ja:酸化テルビウム(III)]]

Category:Acetylides

2009-10-20T14:17:16Z

Su-no-G: +ja

See also: [[Acetylene]]
{{Commons cat|Acetylides}}

[[Category:Carbides]]

[[ar:تصنيف:أسيتيليدات]]
[[ja:Category:アセチリド]]
[[ru:Категория:Ацетилениды]]

Lomefloxacin

2009-10-17T08:31:41Z

Su-no-G: +ja

{{drugbox
| IUPAC_name = (''RS'')-1-ethyl-6,8-difluoro- 7-(3-methylpiperazin-1-yl)- 4-oxo-quinoline-3- carboxylic acid
| image = Lomefloxacin.svg
| CAS_number = 98079-51-7
| ATC_prefix = J01
| ATC_suffix = MA07
| ATC_supplemental = {{ATC|S01|AX17}}
| PubChem = 3948
| DrugBank = APRD01076
| C = 17 | H = 19 | F = 2 | N = 3 | O = 3
| molecular_weight = 351.348 g/mol
| bioavailability =
| protein_bound = 10%
| metabolism =
| elimination_half-life = 8 hours
| excretion =
| pregnancy_AU = 
| pregnancy_US = 
| pregnancy_category =
| legal_AU = 
| legal_UK = 
| legal_US = 
| legal_status =
| routes_of_administration =
}}
'''Lomefloxacin hydrochloride''' (sold under the following brand names in English speaking countries '''Maxaquin''', '''Okacyn''', '''Uniquin'''), is a [[fluoroquinolone]] [[antibiotic]], used to treat [[bacteria]]l infections including [[bronchitis]] and [[urinary tract infection]]s. It is also used to prevent urinary tract infections prior to [[surgery]]. It is taken orally, usually daily for 10-14 days.

October 2008 the FDA added the following Black Box Warning to the product insert for Maxaquin:

WARNING: Fluoroquinolones, including Maxaquin, are associated with an increased risk of tendinitis and tendon rupture in all ages. This risk is further increased in older patients usually over 60 years of age, in patients taking corticosteroid drugs, and in patients with kidney, heart or lung transplants (See WARNINGS). To reduce the development of drug-resistant bacteria and maintain the effectiveness of Maxaquin and other antibacterial drugs, Maxaquin should be used only to treat or prevent infections that are proven or strongly suspected to be caused by bacteria'.<ref>October 2008 revision of the package insert for maxaquin</ref>

Lomefloxacin is unique in that it forms a magnesium [[chelate]] with itself. The chelate is formed between the 2-carbonyl group of two separate lomefloxacin molecules.

==See also==
*[[Fluoroquinolone toxicity]]
*[[Fluoroquinolone]]

==References==
{{reflist}}

{{QuinoloneAntiBiotics}}

[[Category:Fluoroquinolone antibiotics]]
{{antibiotic-stub}}

[[de:Lomefloxacin]]
[[it:Lomefloxacina]]
[[ja:ロメフロキサシン]]

Incubator (egg)

2009-10-13T03:51:35Z

Su-no-G: + ja

{{Orphan|date=October 2009}}
An '''incubator''' is a device simulating [[avian incubation]] by keeping [[egg (biology)|egg]]s warm and in the correct [[humidity]], and if needed to turn them, to hatch them. Modern incubators are electrically-heated with a thermostat and an automatic egg-turner.

A magazine published in Britain during [[World War II|WWII]] described an incubator as "a wooden box, hot water, and a curtain".{{Citation needed|date=October 2009}}

[[Category:Poultry]]
[[Category:Aviculture]]

{{poultry-stub}}

[[ja:孵卵器]]

Incubator (culture)

2009-10-13T03:38:35Z

Su-no-G: modifying ja

[[Image:Bacteriological_incubator.jpg|thumb|right|A Bacteriological incubator]]

In microbiology, an ''incubator'' is a device for controlling the temperature, humidity, and other conditions in which a [[microbiological culture]] is being grown. The simplest incubators are insulated boxes with an adjustable heater, typically going up to 60 to 65 °C (140 to 150 °F), though some can go slightly higher (generally to no more than 100 °C). More elaborate incubators can also include the ability to lower the temperature (via refrigeration), or the ability to control humidity or [[carbon dioxide|CO2]] levels.

Most incubators include a timer; some can also be programmed to cycle through different temperatures, humidity levels, etc. Incubators can vary in size from tabletop to units the size of small rooms.

Incubators also contain certain features such as the shake speed, measured by revolutions per minute. As for temperature, most commonly used is approximately 36 to 37 degrees Celsius. Most bacteria, especially the frequently used [[E. Coli]], grow well under such conditions. For other experimental organisms, such as the budding yeast [[Saccharomyces cerevisiae]], a growth temperature of 30 °C is optimal.

{{Laboratory equipment}}

[[Category:Laboratory equipment]]
[[Category:Microbiology equipment]]
[[Category:Articles lacking sources (Erik9bot)]]

[[de:Inkubator (Biologie)]]
[[es:Incubadora]]
[[fr:Incubateur (biologie)]]
[[ja:インキュベーター (生物学)]]
[[uk:Інкубатор (біологія)]]

Elbs reaction

2009-09-05T07:06:40Z

Su-no-G: +ja

The '''Elbs reaction''' is an [[organic reaction]] describing the [[pyrolysis]] of a [[ortho substitution|ortho]] [[methyl]] substituted [[benzophenone]] to condensed [[polyaromatic]]. The reaction is named after its inventor, the German chemist [[Karl Elbs]] also responsible for the [[Elbs oxidation]]. The reaction was published in 1884 <ref name=elbs>K. Elbs, E. Larsen: ''Ueber Paraxylylphenylketon'', in: ''[[Chemische Berichte|Ber. Dtsch. Chem. Ges.]]'' '''1884''', ''17'', 2847–2849; {{DOI|10.1002/cber.188401702247}}.</ref><ref name=elbs2>K. Elbs: ''Beiträge zur Kenntniss aromatischer Ketone. Erste Mittheilung'', in: ''[[Journal für Praktische Chemie|J. Prakt. Chem.]]'' '''1886''', ''33'', 180–188; {{DOI|10.1002/prac.18860330119}}.</ref>

Elbst however did not correctly interpret the reaction product due to a lack of knowledge about [[naphthalene]] structure.

== Scope ==
The Elbs reaction enables the synthesis of condensed aromatic systems. As already demonstrated by Elbs in 1884 it is possible to obtain [[anthracene]] through [[dehydration]]. Larger aromatic systems like [[pentacene]] are also feasible. This reaction does not take place in a single step but leads first to dihydropentacene that is dehydrogenated in a second step with [[copper]] as a catalyst. <ref name=breit>E. Breitmaier, G. Jung: ''Organische Chemie'', 5. Auflage, S. 183, Thieme Verlag, Stuttgart, '''2005''', ISBN 978-3135415055.</ref>

[[Image:Elbs-Reaktion.png|center|600px|Elbs reaction to anthracite and pentacene]]

The [[acyl]] compounds required for this reaction can be obtained through a [[Friedel-Crafts acylation]] with [[aluminum chloride]]. <ref name=elbs2/><ref name=breit/>

== Variations ==
It is also possible to synthesise [[heterocyclic compound]]s via the Elbs reaction. In 1956 an Elbs reaction of a [[thiophene]] derivative was published. The expected linear product was not obtained due to a change in [[reaction mechanism]] after formation of the first intermediate which caused multiple [[free radical]] reaction steps.<ref>G. M. Badger, B. J. Christie: ''Polynuclear heterocyclic systems. Part X. The elbs reaction with heterocyclic ketones'', in: ''[[Journal of the Chemical Society|J. Chem. Soc.]]'' '''1956''', 3435–3437; {{DOI|10.1039/JR9560003435}}.</ref>

[[Image:Elbs-Hetero.png|center|400px|Heterocyclic Elbs reaction]]

==References==
<references />

[[Category:Organic reactions]]
[[Category:Name reactions]]

[[de:Elbs-Reaktion]]
[[ja:エルブス反応]]
[[ru:Реакция_Эльбса]]

Epimer

2009-09-05T06:13:31Z

Su-no-G: +ja

In [[chemistry]], '''epimers''' are [[diastereomers]] that differ in configuration of only one [[stereogenic center]]. Diastereomers are a class of [[stereoisomers]] that are non-superposable, non-mirror images of one another, unlike [[enantiomers]] which are non-superposable mirror images of one another.<ref>March, Jerry and Smith, Michael B.. March's Advanced Organic Chemistry: ''Reactions, Mechanisms and Structure''. ''6th ed.'' Hoboken, NJ: momo peon & Sons, Inc., 2007.</ref>

[[image:Glucoseab.png|center|350px]]
For example, the [[sugar]]s α-glucose and β-glucose are epimers. In α-glucose, the -OH group on the first (anomeric) carbon is in the direction opposite the methylene group (in the [[axial]] position). In β-glucose, the -OH group is oriented in the same direction as the methylene group (in the [[equatorial]] position).<ref>[http://www.biotopics.co.uk/as/glucose2.html Structure of the glucose molecule]</ref> These two molecules are both epimers and [[anomers]].

[[image:Sugars.PNG|center|350px]]

In this case, β-D-glucopyranose and β-D-mannopyranose are epimers because they differ only in the stereochemistry at the 2 position. The hydroxyl group in β-D-glucopyranose is [[Cyclohexane conformation#Chair conformation|equatorial]] (in the "plane" of the ring) while in β-D-mannopyranose the 2 hydroxyl group is [[Cyclohexane conformation#Chair conformation|axial]] (up from the "plane" of the ring). These two molecules are epimers but not anomers.

In chemical nomenclature, one of the epimeric pairs is given the prefix '''epi-''' for example in [[quinine]] and ''epi-quinine''. When the pairs are enantiomers, the prefix becomes '''ent-'''.

==References==
<references/>

== External links ==
* {{GoldBookRef | title = epimers | file = E02167}}

[[Category:Stereochemistry]]

[[ar:صنو]]
[[ca:Epímer]]
[[es:Epímero]]
[[fr:Épimère]]
[[id:Epimer]]
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[[he:אפימר]]
[[ms:Epimer]]
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[[pl:Epimery]]
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[[zh:差向异构]]

Cyclophane

2009-09-04T15:28:17Z

Su-no-G: +ja

[[Image:Cyclophanes.png|300px|right|Scheme 1. Cyclophanes]]A '''cyclophane''' is a [[hydrocarbon]] consisting of an [[aromatic]] unit (typically a [[benzene]] ring) and an [[aliphatic]] [[Chain (sequence)|chain]] that forms a [[bridge]] between two non-adjacent positions of the aromatic ring. More complex derivatives with multiple aromatic units and bridges forming [[cage]]like [[structure]]s are also known. Cyclophanes are well-studied in [[organic chemistry]] because they adopt unusual chemical conformations due to build-up of [[Strain (chemistry)|
strain]]. Despite this, cyclophane structures are not unknown to biomolecules.

[[Image:-6-cyclophanes.png|300px|right|Scheme 2. [6]paracyclophanes]]Basic cyclophane types are '''[n]metacyclophanes''' ('''I''') in ''scheme 1'', '''[n]paracyclophanes''' ('''II''') and '''[n,n']cyclophanes''' ('''III'''). the prefixes ''meta'' and ''para'' correspond to the usual [[arene substitution patterns]] and n refers to the number of atoms making up the bridge.

==Structure==
Paracyclophanes adopt the [[boat conformation]] normally observed in cyclohexanes but are still able to retain [[aromaticity]]. The smaller the value of n the larger the deviation from aromatic planarity. In [6]paracyclophane which one of the stable cyclophanes [[X-ray crystallography]] shows that the aromatic bridgehead carbon atom makes an angle of 20.5° with the plane. The [[benzyl]] carbons deviate by another 20.2°. The carbon to carbon bond length alternation has increased from 0 for [[benzene]] to 39 [[picometer|pm]].<ref>''Synthesis and molecular structure of (Z)-[6]Paracycloph-3-enes'' Yoshito Tobe, Kenichi Ueda, Teruhisa Kaneda, Kiyomi Kakiuchi, Yoshinobu Odaira, Yasushi Kai, Nobutami Kasai [[J. Am. Chem. Soc.]]; '''1987'''; 109(4); 1136-1144. [http://pubs.acs.org/cgi-bin/abstract.cgi/jacsat/1987/109/i04/f-pdf/f_ja00238a024.pdf Abstract]</ref><ref>J. Hunger, C. Wolff, W. Tochtermann, E-M. Peters, K.Peters, H.G. von Schering [[Chem. Ber.]], 119, 2698 ('''1986''')</ref>

In organic reactions [6]cyclophane tends to react as a diene derivative and not as an aromat. With [[bromine]] it gives 1,4-addition and with [[chlorine]] the 1,2-addition product forms.

Yet the [[proton NMR]] spectrum displays the aromatic protons and their usual deshielded positions around 7.2 ppm and the central methylene protons in the aliphatic bridge are even severely deshielded to a position of around - 0.5 ppm, that is, even deshielded compared to the internal reference [[tetramethylsilane]]. With respect to the [[diamagnetic ring current]] criterion for aromaticity this cyclophane is still aromatic.
[[Image:Incyclophanes.png|right|400px|In-cyclophanes, pyridinophanes and superphanes]]

One particular research field in cyclophanes involves probing just how close atoms can get above the center of an aromatic nucleus.<ref>''Molecular Iron Maidens: Ultrashort Nonbonded Contacts in Cyclophanes
and Other Crowded Molecules'' Robert A. Pascal, Jr Eur. J. Org. Chem. '''2004''', 3763-3771
{{DOI|10.1002/ejoc.200400183}}</ref> In so-called '''in-cyclophanes''' with part of the molecule forced to point '''in'''wards one of the closest hydrogen to arene distances experimentally determined is just 168 [[picometer]].

A non-bonding nitrogen to arene distance of 244 pm is recorded for a pyridinophane and in the totally weird [[superphane]] the two benzene rings are separated by a mere 262 pm. Another representative of this group are [[in-methylcyclophane]]s.

==Synthetic methods==
[6]paracyclophane can be synthesized<ref>''[6]Paracyclophane'' Vinayak V. Kane, Anthony D. Wolf, Maitland Jones, , Jr. [[J. Am. Chem. Soc.]]; '''1974'''; 96(8); 2643-2644. [http://pubs.acs.org/cgi-bin/abstract.cgi/jacsat/1974/96/i08/f-pdf/f_ja00815a070.pdf Abstract]</ref><ref>''Interconversion of [6]paracyclophane and 1,4-hexamethylene(Dewar benzene)'' Seetha L. Kammula, Linda D. Iroff, Maitland Jones, , Jr. J. W. Van Straten, W. H. De Wolf, F. Bickelhaupt [[J. Am. Chem. Soc.]]; '''1977'''; 99(17); 5815-5815. [http://pubs.acs.org/cgi-bin/abstract.cgi/jacsat/1977/99/i17/f-pdf/f_ja00459a055.pdf Abstract]</ref> in the laboratory by a [[Bamford-Stevens reaction]] with [[spiro compound|spiro]] [[ketone]] '''1''' in ''scheme 3'' rearranging in a [[pyrolysis]] reaction through the [[carbene]] intermediate '''4'''. The cyclophane can be [[photochemistry|photochemically]] converted to the [[Dewar benzene]] '''6''' and back again by application of heat. A separate route to the Dewar form is by a cationic [[silver perchlorate]] induced [[rearrangement reaction]] of the bicyclopropenyl compound '''7'''.

[[Image:-6-cyclophaneSynthesis.png|500px|center|Scheme 3. [6]paracyclophane synthesis]]

'''Metaparacyclophanes''' constitute another class of cyclophans like the [14][14]metaparacyclophane<ref>''[14][14]Metaparacyclophane: First Example of an [m][n]Metaparacyclophane''Chunmei Wei, Kai-For Mo, and Tze-Lock Chan [[J. Org. Chem.]]; '''2003'''; 68(7) pp 2948 - 2951; (Note) [http://dx.doi.org/10.1021/jo0267044 Abstract]</ref> in ''scheme 4''<ref>Scheme 4. Reaction scheme: with para-ring in place ring closure of meta part by [[nucleophilic displacement]] of [[alkyl halide|dibromide]] by [[sulfide|disulfide]]. Then [[organic oxidation|oxidation]] of sulfide to [[sulfone]] by [[hydrogen peroxide]] followed by in-situ [[Ramberg-Bäcklund Reaction]] with halide donor dibromodifluoromethane and base [[potassium hydroxide]]. Final step [[hydrogenation]] pf [[alkene]] by hydrogen and [[palladium on carbon]]</ref> featuring a in-situ [[Ramberg-Bäcklund Reaction]] converting the [[sulfone]] '''3''' to the [[alkene]] '''4'''.

[[Image:Metaparacyclophane.png|600px|center|Scheme 4. [14][14]metaparacyclophane]]

== Naturally occurring cyclophanes ==
Despite carrying strain, the cyclophane motif does exist in nature. One example of a metacyclophane is [[cavicularin]].

Haouamine A is a paracyclophane found in a certain species of [[tunicate]]. Because of its potential application as an anticancer [[drug]] it is also available from [[total synthesis]] via an [[alkyne]] - [[pyrone]] [[Diels-Alder reaction]] in the crucial step with expulsion of carbon dioxide (''scheme 5'').<ref>''Total Synthesis of (±)-Haouamine A'' Phil S. Baran and Noah Z. Burns [[J. Am. Chem. Soc.]]; '''2006'''; ASAP Web Release Date: 04-Mar-2006; [http://dx.doi.org/10.1021/ja0602997 Abstract] The authors mark the biosynthetic origin as ''mysterious''</ref>

[[Image:Haouamine.png|500px|center|Scheme 5. Haouamine A]]

In this compound the deviation from planarity is 13° for the benzene ring and 17° for the bridgehead carbons.<ref>''Synthesis of the 3-Aza-[7]-paracyclophane Core of Haouamine A and B'' Peter Wipf and Markus Furegati Org. Lett.; '''2006'''; 8(9) pp 1901 - 1904; (Letter) [http://dx.doi.org/10.1021/ol060455e Abstract]</ref> An alternative cyclophane formation strategy in ''scheme 6''<ref>Scheme 6. Reaction scheme: step I [[elimination reaction]] of methanol with [[trifluoroethanol]] and [[diisopropylamine]], step II [[methylation]] with [[dimethyl sulfate]]. Ns = [[Nosylate]] </ref> was developed based on [[aromatization]] of the ring well after the formation of the bridge.

[[Image:Haouamine aromatization.png|500px|center|Scheme 6. Haouamine cyclophane substructure synthesis]]

==[n,n]Paracyclophanes==
A well exploited member of the [n,n]paracyclophane family is '''[2,2]paracyclophane'''. One method for its preparation is by a [[Hofmann elimination|1,6-Hofmann elimination]]:<ref>[[Organic Syntheses]], Coll. Vol. 5, p.883 ('''1973'''); Vol. 42, p.83 ('''1962''') [http://www.orgsyn.org/orgsyn/orgsyn/prepContent.asp?prep=cv5p0883 Link].</ref>

[[Image:2,2-paracyclophane.png|center|400px|Scheme 7. 2,2-paracyclophane synthesis]]

The [2.2]paracyclophane-1,9-diene has been applied in [[Ring opening metathesis polymerisation|ROMP]] to a [[poly(p-phenylene vinylene)]] with alternating [[cis-alkene]] and [[trans-alkene]] bonds using [[Grubbs' catalyst|Grubbs' second generation catalyst]]:<ref>''Soluble Poly(p-phenylenevinylene)s through Ring-Opening Metathesis Polymerization'' Chin-Yang Yu and Michael L. Turner [[Angew. Chem. Int. Ed.]] '''2006''', 45, 7797 –7800 {{DOI|10.1002/anie.200602863}}</ref>

[[Image:2,2-paracyclophanedienePolymerization.png|center|400px|Scheme 8. 2,2-paracyclophane-1,9-diene polymerization]]

The driving force for ring-opening and polymerization is strain relief. The reaction is believed to be a [[living polymerization]] due to the lack of competing reactions.

Because the two benzene rings are in close proximity this cyclophane type also serves as guinea pig for [[photochemical]] [[dimerization]] reactions as illustrated by this example:<ref>''Photoreaction of a 2,11-Diaza[3.3]paracyclophane Derivative: Formation of Octahedrane by Photochemical Dimerization of Benzene'' Hideki Okamoto, Kyosuke Satake, Hiroyuki Ishida, and Masaru Kimura [[J. Am. Chem. Soc.]]; '''2006'''; 128(51) pp 16508 - 16509; (Communication) {{DOI|10.1021/ja067350r}}</ref>

[[Image:CyclophaneOctahedraneFormation.png|center|400px|Formation of Octahedrane by Photochemical Dimerization of Benzene]]

The product formed has an [[octahedrane]] skeleton. Interestingly when the [[amine]] group is replaced by a [[methylene]] group no reaction takes place: the dimerization requires [[through-bond electron transfer|through-bond overlap]] between the aromatic [[pi electron]]s and the [[sigma bond|sigma electrons]] in the C-N bond in the reactants [[LUMO]].

==References==
<div class="references-small"><references/></div>

[[Category:Hydrocarbons]]

[[fr:Cyclophane]]
[[it:Ciclofani]]
[[ja:シクロファン]]
[[pl:Cyklofany]]
[[zh:环芬]]

Cycloheptatriene

2009-09-01T14:31:43Z

Su-no-G: +ja

{{Otheruses4|a chemical compound|for other uses|CHT}}
{{chembox
| ImageFile = Cycloheptatriene.png
| ImageSize =
| IUPACName =
| OtherNames = CHT, 1,3,5-cycloheptatriene
| Section1 = {{Chembox Identifiers
| CASNo = 544-25-2
| SMILES=C1C=CC=CC=C1
| PubChem =
}}
| Section2 = {{Chembox Properties
| Formula = '''[[Carbon|C]]'''7'''[[Hydrogen|H]]'''8
| MolarMass = 92.141 g mol-1
| Appearance =
| Density =
| MeltingPt = -80 °C
| BoilingPt = 116 °C
| Solubility = Insoluble in water
}}
| Section3 = {{Chembox Hazards
| MainHazards =
| FlashPt =
| Autoignition =
| RPhrases = {{R10}} {{R11}} {{R21}} {{R23/24/25}} {{R36/37/38}}
| SPhrases = {{S9}} {{S16}} {{S23}} {{S28}}A {{S33}} {{S36/37}} {{S45}}
}}
}}
'''Cycloheptatriene''' or '''CHT''' is a colourless liquid that has been of recurring theoretical interest in [[organic chemistry]]. It is widely used as a ligand in [[organometallic chemistry]] and as a building block in [[organic synthesis]].

Cycloheptatriene is not [[aromatic]], and the ring is not planar, due to the presence of the -[[Carbon|C]][[Hydrogen|H]]2- group. Removal of a [[hydride]] ion from the [[methylene]] group gives the planar and aromatic cycloheptatriene cation, also called the [[tropylium]] ion. A practical route to this cation employs [[Phosphorus pentachloride|PCl5]] as the oxidant.<ref>{{cite journal
|author = Conrow, K.
|title = Tropylium Fluoroborate
|journal = Organic Syntheses, Collected Volume 5,
|pages = 1138
|year = 1973
|url= http://www.orgsyn.org/orgsyn/pdfs/CV5P1138.pdf}}</ref>

Although [[Albert Ladenburg]] discovered cycloheptatriene in 1881 by the decomposition of [[tropine]],<ref>{{cite journal
| author = [[Albert Ladenburg|A. Ladenburg]]
| title = Die Constitution des Atropins
| journal = [[Liebigs Annalen|Justus Liebig's Annalen der Chemie]]
| volume = 217
| issue = 1
| pages = 74–149
| year = 1883
| doi= 10.1002/jlac.18832170107}}</ref><ref>{{cite journal
| author = [[Albert Ladenburg|A. Ladenburg]]
| title = Die Zerlegung des Tropines
| journal = [[Chemische Berichte|Berichte der Deutschen chemischen Gesellschaft]]
| volume = 14
| issue =
| pages = 2126–2131
| year = 1881
| url= http://gallica.bnf.fr/ark:/12148/bpt6k906939/f537.chemindefer
| doi = 10.1002/cber.188101402127}}</ref> the structure was finally proven by the synthesis of [[Richard Willstätter]] in 1901. This synthesis started from cycloheptanone and proved therefore the seven membered ring structure of the compound.<ref>{{cite journal
| author = [[Richard Willstätter|R. Willstätter]]
| title = Synthesen in der Tropingruppe. I. Synthese des Tropilidens
| journal = [[Liebigs Annalen|Justus Liebig's Annalen der Chemie]]
| volume = 317
| issue = 2
| pages = 204–265
| year = 1901
| doi= 10.1002/jlac.19013170206}}</ref>

Cycloheptatriene can be obtained in the laboratory by [[photochemical reaction]] of [[benzene]] with [[diazomethane]] or the pyrolysis of the adduct of [[cyclohexene]] and [[dichlorocarbene]].<ref>{{cite journal
| author = H.E. Winberg
| title = Synthesis of Cycloheptatriene
| journal = [[Journal of Organic Chemistry]]
| volume = 24
| issue = 2
| pages = 264–265
| year = 1959
| doi= 10.1021/jo01084a635}}</ref>

Another classic reaction for (a cycloheptatriene derivative) called the '''Buchner ring enlargement''' starts from reaction of [[benzene]] with [[ethyl diazoacetate]] to the corresponding [[norcaradiene]] [[carboxylic acid]] which at high temperatures rearranges with [[Ring expansion reaction|ring expansion]] to the cycloheptatriene carboxylic acid ethyl ester <ref>Buchner, et al., Ber., 18, 2377 ('''1885''');</ref> <ref>For a variation: ''Studies on the Polymethylbenzenes. IX. Addition of Ethyl Diazoacetate to Durene'' Lee Irvin Smith, Pliny O. Tawney [[J. Am. Chem. Soc.]]; '''1934'''; 56(10); 2167-2169. {{DOI|10.1021/ja01325a054}}</ref>.

[[Cyclooctatetraene]] and cycloheptatriene are used as a [[Spin triplet|triplet]] quencher for [[rhodamine 6G]] [[dye laser]]s.<ref>{{cite journal
| author = Tomi Nath Das, K. lndira Priyadarsini
| title = Triplet of Cyclooctatetraene : Reactivity and Properties
| journal = Journal of Chemical Society Faraday Transaction
| volume = 90
| issue = 7
| pages = 963–968
| year = 1994
| url=
| doi = 10.1039/ft9949000963 }}</ref><ref>{{cite journal
| author = R. Pappalardo, H. Samelson, and A. Lempicki
| title = Long Pulse Laser Emission From Rhodamine 6G Using Cyclooctatetraene
| journal = [[Applied Physics Letters]]
| volume = 16
| issue = 7
| pages = 267–269
| year = 1970
| doi= 10.1063/1.1653190}}</ref>

==See also==
* [[Cyclopentadiene]]
* [[Cyclooctatetraene]]
* [[Benzene]]

==References==
{{Reflist}}

==External links==
*

[[Category:Cycloalkenes]]

[[de:Cycloheptatrien]]
[[fr:Cycloheptatriène]]
[[ja:シクロヘプタトリエン]]

Silanol

2009-08-30T04:55:44Z

Su-no-G: +ja

'''Silanols''' are [[chemical compound|compound]]s containing [[silicon]] [[atoms]] to which [[hydroxy]] [[substituent]]s bond directly. They are similar to [[alcohol]]s just as [[silane]]s are similar to [[alkane]]s.

Silanols are named, when the [[hydroxy]] group is the principal one, by adding the suffix –ol to their mother name.
If the [[hydroxy]] group is not the principal one, silanols are named by using the prefix hydroxy- according to the substitutive nomenclature.
These rules are almost the same as those of [[alcohol]], with the exception that [[silane]] is used as the mother hydride.

==History==
Silanols were first synthesized in 1871 by Albert Ladenburg. The first example was triethylsilanol. At that time, they were called silicols, a word that he coined.

==Synthesis==
Silanols are generally synthesized by [[hydrolysis]] of halosilane, alkoxysilane, or aminosilane; by [[oxidation]] of hydrosilane; or by [[hydrolysis]] of arylsilane in the presence of strong [[acid]].

==Properties==
Silanols are generally [[dehydration reaction|dehydrated]] very easily, giving disiloxanes in the presence of [[acid]], [[base (chemistry)|base]], or even [[heat]].
Because of this property of self-condensation, the synthesis and isolation of silanols are difficult.

Silanols have [[hydroxy]] substituents, and so they have [[hydrogen bonding]] to each other in solution and even in crystals.

Silanols can also be crosslinked using borax, or boric acid, to form 3-dimensional silicon gels.

Silanols exist not only as [[chemical compound]]s but also on the surface of [[silica]].
From the viewpoint of [[organometallic chemistry]], [[silica]] can be considered as an enormous [[ligand]], and it is used as supports for [[catalyst]]s of many reactions.
In [[chromatography]], derivitization of accessible silanol groups in a bonded [[stationary phase]] with [[trimethylsilyl]] groups is referred to as [[endcapping]].

==See also==
* [[Trimethylsilanol]]
* [[Diphenylsilanediol]]
* [[Organosilicon]]

[[Category:Inorganic compounds]]
[[Category:Silicon compounds]]
[[Category:Organosilicon compounds]]
[[Category:Articles lacking sources (Erik9bot)]]

[[de:Silanole]]
[[ja:シラノール]]

Trimethylsilylacetylene

2009-08-30T03:45:32Z

Su-no-G: +ja

{{Chembox
| ImageFile = Trimethylsilylacetylene.PNG
| ImageSize =
| IUPACName = ethynyl-trimethyl-silane
| OtherNames =
| Section1 = {{Chembox Identifiers
| CASNo = 1066-54-2
| PubChem = 66111
| ChemSpiderID = 59499
| SMILES = C#C[Si](C)(C)C
| InChI = InChI=1S/C5H10Si/c1-5-6(2,3)4/h1H,2-4H3
}}
| Section2 = {{Chembox Properties
| C = 5 | H = 10 | Si = 1
| Appearance = colorless liquid
| Density = 0.69 g/mL
| MeltingPt =
| BoilingPtC = 53
| Solubility =
}}
| Section3 = {{Chembox Hazards
| ExternalMSDS = [http://fscimage.fishersci.com/msds/20433.htm External MSDS]
| EUClass = {{Hazchem F}}
| RPhrases = {{R11}}
| SPhrases = {{S16}} {{S24/25}} {{S29}} {{S33}} {{S9}}
| FlashPt =
| Autoignition =
}}
}}
'''Trimethylsilylacetylene''' is an [[acetylene]] protected on one end by the [[trimethylsilyl group]]. It is popularly used in alkynylations, e.g. the [[Sonogashira reaction]]. After [[desilylation]] (e.g. with [[TBAF]], the ethynyl group is introduced. Using a protected alkyne, as opposed to acetylene gas, prevents further (undesired) coupling reactions.

Trimethylsilylacetylene may be prepared in a manner similar to other silyl compounds: deprotonation of [[acetylene]] with a [[Grignard reagent]], followed by reaction with [[trimethylsilyl chloride]].<ref>{{OrgSynth | title = Trimethylsilylacetylene | author = Andrew B. Holmes and Chris N. Sporikou | prep = cv8p0606 | collvol = 8 | collvolpages = 606 | year = 1993}}</ref>

==References==
<references/>

[[Category:Silanes]]
[[Category:Alkynes]]
[[ja:トリメチルシリルアセチレン]]

Sodium amide

2009-08-29T08:34:36Z

Su-no-G: +ja

{{chembox
| ImageFile = Sodium-amide-3D-balls-B.png

| Name = Sodium amide
| OtherNames = Sodamide
| Section1 = {{Chembox Identifiers
| CASNo = 7782-92-5
| CASNo_Ref = {{cascite}}
| PubChem = 24533
| RTECS =
}}
| Section2 = {{Chembox Properties
| Formula = NaNH2
| MolarMass = 39.0124 g/mol
| Appearance = gray powder (colourless when pure)
| Density = 1.39 g/cm3
| Solubility = reacts
| MeltingPt = 210 °C
| BoilingPt = 400 °C
| pKa = 38 <ref>Buncel; Menon J. Organomet. Chem. 1977, 141, 1</ref>
}}
| Section3 = {{Chembox Structure
| Coordination =
| CrystalStruct = orthogonal
}}
| Section7 = {{Chembox Hazards
| EUIndex = Not listed
| FlashPt = 4.44 °C
| NFPA-H = 3
| NFPA-F = 2
| NFPA-R = 3
| NFPA-O = W
| Autoignition = 450 °C
}}
| Section8 = {{Chembox Related
| OtherAnions = [[Sodium bis(trimethylsilyl)amide]]
| OtherCations = [[Potassium amide]]
| OtherCpds = [[Ammonia]]
}}
}}

'''Sodium amide''', commonly called sodamide, is the [[chemical compound]] with the [[chemical formula|formula]] NaNH2. This solid, which is dangerously reactive toward water, is white when pure, but commercial samples are typically gray due to the presence of small quantities of metallic iron from the manufacturing process. Such impurities do not usually affect the utility of the [[reagent]]. NaNH2 has been widely employed as a strong base in [[organic synthesis]].

==Preparation and structure==
Sodium amide can be prepared by the reaction of [[sodium]] with ammonia gas,<ref>Bergstrom, F. W. (1955). "[http://www.orgsyn.org/orgsyn/prep.asp?prep=cv3p0778 Sodium amide]". ''[[Org. Synth.]] Coll. Vol.'' '''3''':778.</ref> but it is usually prepared by the reaction in liquid ammonia using [[iron(III) nitrate]] as a [[catalyst]]. The reaction is fastest at the boiling point of the ammonia, ca. -33 °C.<ref>Greenlee, K. W.; Henne, A. L. (1946). "Sodium Amide". ''Inorganic Syntheses'' '''2''':128–35.</ref>
:2 Na + 2 NH3 → 2 NaNH2 + H2

NaNH2 is a salt-like material and as such, crystallizes as an infinite polymer.<ref>Zalkin, A.; Templeton, D. H. "The Crystal Structure Of Sodium Amide" Journal of Physical Chemistry 1956, Volume 60, pp 821 - 823. DOI: 10.1021/j150540a042</ref> The geometry about sodium is tetrahedral.<ref>Wells, A.F. (1984) Structural Inorganic Chemistry, Oxford: Clarendon Press. ISBN 0-19-855370-6.</ref> In ammonia, NaNH2 forms conductive solutions, consistent with the presence of Na(NH3)6+ and NH2- anions.

==Uses==
Sodium amide is used in the industrial production of [[Indigo dye|indigo]], [[hydrazine]], and [[sodium cyanide]].<ref>{{Merck12th}}</ref> It is the reagent of choice for the drying of [[ammonia]] (liquid or gaseous) and is also widely used as a strong [[base (chemistry)|base]] in organic chemistry, often in liquid ammonia solution. One of the main advantages to the use of sodamide is that it is an excellent base and rarely serves as a nucleophile. It is however poorly soluble and its use has been superseded by the related reagents such as [[sodium hydride]], [[sodium bis(trimethylsilyl)amide]] (NaHMDS), and [[lithium diisopropylamide]] (LDA).

===Preparation of alkynes===
Sodium amide induces the loss of two molecules of [[hydrogen bromide]] from a [[Vicinal (chemistry)|vicinal]] dibromoalkane to give a [[carbon-carbon triple bond]], as in the preparation of [[phenylacetylene]] below.<ref>Campbell, Kenneth N.; Campbell, Barbara K. (1950). "[http://www.orgsyn.org/orgsyn/prep.asp?prep=cv4p0763 Phenylacetylene]". ''[[Org. Synth.]]'' '''30''':72; ''Coll. Vol.'' '''4''':763.</ref>
Normally two equivalents of sodium amide yields the desired alkyne. However, three equivalents are necessary in the preparation of a terminal alkyne because, as this alkyne forms, its acidic terminal hydrogen immediately protonates an equivalent amount of base.

[[Image:Phenylacetylene prepn.png|300px]]

[[Hydrogen chloride]] and/or [[ethanol]] can also be eliminated in this way,<ref>Jones, E. R. H.; Eglinton, Geoffrey; Whiting, M. C.; Shaw, B. L. (1954). "[http://www.orgsyn.org/orgsyn/prep.asp?prep=cv4p0404 Ethoxyacetylene]". ''[[Org. Synth.]]'' '''34''':46; ''Coll. Vol.'' '''4''':404. 
Bou, Anna; Pericàs, Miquel A.; Riera, Antoni; Serratosa, Fèlix (1987). "[http://www.orgsyn.org/orgsyn/prep.asp?prep=cv8p0161 Dialkoxyacetylenes: di-''tert''-butoxyethyne, a valuable synthetic intermediate]". ''[[Org. Synth.]]'' '''65''':68; ''Coll. Vol.'' '''8''':161. 
Magriotis, Plato A.; Brown, John T. (1995). "[http://www.orgsyn.org/orgsyn/prep.asp?prep=cv9p0656 Phenylthioacetylene]". ''[[Org. Synth.]]'' '''72''':252; ''Coll. Vol.'' '''9''':656. 
Ashworth, P. J.; Mansfield, G. H.; Whiting, M. C. (1955). "[http://www.orgsyn.org/orgsyn/prep.asp?prep=cv4p0128 2-Butyn-1-ol]". ''[[Org. Synth.]]'' '''35''':20; ''Coll. Vol.'' '''4''':128.</ref> as in the preparation of [[1-ethoxy-1-butyne]].<ref>Newman, Melvin S.; Stalick, W. M. (1977). "[http://www.orgsyn.org/orgsyn/prep.asp?prep=cv6p0564 1-Ethoxy-1-butyne]". ''[[Org. Synth.]]'' '''57''':65; '''6''':564.</ref>

[[Image:Ethoxybutyne prepn.png|500px]]

===Cyclization reactions===
Where there is no β-hydrogen to be eliminated, cyclic compounds may be formed, as in the preparation of [[methylenecyclopropane]] below.<ref>Salaun, J. R.; Champion, J.; Conia, J. M. (1977). "[http://www.orgsyn.org/orgsyn/prep.asp?prep=cv6p0320 Cyclobutanone from methylenecyclopropane ''via'' oxaspiropentane]". ''[[Org. Synth.]]'' '''57''':36; ''Coll. Vol.'' '''6''':320.</ref>

[[Image:Methylenecyclopropane prepn.png|400px]]

[[Cyclopropene]]s,<ref>Nakamura, Masuharu; Wang, Xio Qun; Isaka, Masahiko; Yamago, Shigeru; Nakamura, Eiichi (2003). "[http://www.orgsyn.org/orgsyn/prep.asp?prep=v80p0144 Synthesis and (3+2)-cycloaddition of a 2,2-dialkoxy-1-methylenecyclopropane: 6,6-dimethyl-1-methylene-4,8-dioxaspiro(2.5)octane and ''cis''-5-(5,5-dimethyl-1,3-dioxan-2-ylidene)hexahydro-1(2''H'')-pentalen-2-one]". ''[[Org. Synth.]]'' '''80''':144.</ref> [[aziridine]]s<ref>Bottini, Albert T.; Olsen, Robert E. (1964). "[http://www.orgsyn.org/orgsyn/prep.asp?prep=cv5p0541 ''N''-Ethylallenimine]". ''[[Org. Synth.]]'' '''44''':53; ''Coll. Vol.'' '''5''':541.</ref>
and [[cyclobutane]]s<ref>Skorcz, J. A.; Kaminski, F. E. (1968). "[http://www.orgsyn.org/orgsyn/prep.asp?prep=cv5p0263 1-Cyanobenzocyclobutene]". ''[[Org. Synth.]]'' '''48''':55; ''Coll. Vol.'' '''5''':263.</ref> may be formed in a similar manner.

===Deprotonation of carbon and nitrogen acids===
Carbon acids which can be [[Deprotonation|deprotonated]] by sodium amide in liquid ammonia include terminal [[alkyne]]s,<ref>Saunders, J. H. (1949). "[http://www.orgsyn.org/orgsyn/prep.asp?prep=cv3p0416 1-Ethynylcyclohexanol]". ''[[Org. Synth.]]'' '''29''':47; ''Coll. Vol.'' '''3''':416. 
Peterson, P. E.; Dunham, M. (1977). "[http://www.orgsyn.org/orgsyn/prep.asp?prep=cv6p0273 (''Z'')-4-Chloro-4-hexenyl trifluoroacetate]". ''[[Org. Synth.]]'' '''57''':26; ''Coll. Vol.'' '''6''':273. 
Kauer, J. C.; Brown, M. (1962). "[http://www.orgsyn.org/orgsyn/prep.asp?prep=cv5p1043 Tetrolic acid]". ''[[Org. Synth.]]'' '''42''':97; ''Coll. Vol.'' '''5''':1043.</ref>
methyl [[ketone]]s,<ref>Coffman, Donald D. (1940). "[http://www.orgsyn.org/orgsyn/prep.asp?prep=cv3p0320 Dimethylethynylcarbinol]". ''[[Org. Synth.]]'' '''20''':40; ''Coll. Vol.'' '''3''':320. 
Hauser, C. R.; Adams, J. T.; Levine, R. (1948). "[http://www.orgsyn.org/orgsyn/prep.asp?prep=cv3p0291 Diisovalerylmethane]". ''[[Org. Synth.]]'' '''28''':44; ''Coll. Vol.'' '''3''':291.</ref>
[[cyclohexanone]],<ref>Vanderwerf, Calvin A.; Lemmerman, Leo V. (1948). "[http://www.orgsyn.org/orgsyn/prep.asp?prep=cv3p0044 2-Allylcyclohexanone]". ''[[Org. Synth.]]'' '''28''':8; ''Coll. Vol.'' '''3''':44.</ref>
[[phenylacetic acid]] and its derivatives<ref>Hauser, Charles R.; Dunnavant, W. R. (1960). "[http://www.orgsyn.org/orgsyn/prep.asp?prep=cv5p0526 α,β-Diphenylpropionic acid]". ''[[Org. Synth.]]'' '''40''':38; ''Coll. Vol.'' '''5''':526. 
Kaiser, Edwin M.; Kenyon, William G.; Hauser, Charles R. (1967). "[http://www.orgsyn.org/orgsyn/prep.asp?prep=cv5p0559 Ethyl 2,4-diphenylbutanoate]". ''[[Org. Synth.]]'' '''47''':72; ''Coll. Vol.'' '''5''':559. 
Wawzonek, Stanley; Smolin, Edwin M. (1951). "[http://www.orgsyn.org/orgsyn/prep.asp?prep=cv4p0387 α,β-Diphenylcinnamonitrile]". ''[[Org. Synth.]]'' '''31''':52; ''Coll. Vol.'' '''4''':387.</ref>
and [[diphenylmethane]].<ref>Murphy, William S.; Hamrick, Phillip J.; Hauser, Charles R. (1968). "[http://www.orgsyn.org/orgsyn/prep.asp?prep=cv5p0523 1,1-Diphenylpentane]". ''[[Org. Synth.]]'' '''48''':80; ''Coll. Vol.'' '''5''':523.</ref>
[[Acetylacetone]] loses two protons to form a [[Anion|dianion]].<ref>Hampton, K. Gerald; Harris, Thomas M.; Hauser, Charles R. (1971). "[http://www.orgsyn.org/orgsyn/prep.asp?prep=cv6p0928 Phenylation of diphenyliodonium chloride: 1-phenyl-2,4-pentanedione]". ''[[Org. Synth.]]'' '''51''':128; ''Coll. Vol.'' '''6''':928. 
Hampton, K. Gerald; Harris, Thomas M.; Hauser, Charles R. (1967).</ref>

[[Image:Double deprotonation of acetylacetone.png|300px]]

Sodium amide will also deprotonate [[indole]]<ref>Potts, K. T.; Saxton, J. E. (1960). "[http://www.orgsyn.org/orgsyn/prep.asp?prep=cv5p0769 1-Methylindole]". ''[[Org. Synth.]]'' '''40''':68; ''Coll. Vol.'' '''5''':769.</ref> and [[piperidine]].<ref>Bunnett, J. F.; Brotherton, T. K.; Williamson, S. M. (1960). "[http://www.orgsyn.org/orgsyn/prep.asp?prep=cv5p0816 ''N''-β-Naphthylpiperidine]". ''[[Org. Synth.]]'' '''40''':74; ''Coll. Vol.'' '''5''':816.</ref>

===Other reactions===
*Rearrangement with orthodeprotonation<ref>Brazen, W. R.; Hauser, C. R. (1954). "[http://www.orgsyn.org/orgsyn/prep.asp?prep=cv4p0585 2-Methylbenzyldimethylamine]". ''[[Org. Synth.]]'' '''34''':61; ''Coll. Vol.'' '''4''':585.</ref>
*Oxirane synthesis (by carbene reaction?)<ref>Allen, C. F. H.; VanAllen, J. (1944). "[http://www.orgsyn.org/orgsyn/prep.asp?prep=cv3p0727 Phenylmethylglycidic ester]". ''[[Org. Synth.]]'' '''24''':82; ''Coll. Vol.'' '''3''':727.
</ref>
*Indole synthesis<ref> Allen, C. F. H.; VanAllen, James (1942). "[http://www.orgsyn.org/orgsyn/prep.asp?prep=cv3p0597 2-Methylindole]". ''[[Org. Synth.]]'' '''22''':94; ''Coll. Vol.'' '''3''':597.</ref>
*[[Chichibabin reaction]]

==Safety==
Sodium amide reacts violently with water to produce [[ammonia]] and [[sodium hydroxide]] and will burn in air to give oxides of [[sodium]] and [[nitrogen]].
:NaNH2 + H2O → NH3 + NaOH
:2NaNH2 + 4O2 → [[Sodium peroxide|Na2O2]] + 2[[Nitrogen dioxide|NO2]] + 2H2O
In the presence of limited quantities of air and moisture, such as in a poorly closed container, explosive mixtures of oxidation products can form. This is accompanied by a yellowing or browning of the solid. As such, sodium amide should always be stored in a tightly closed container, if possible under an atmosphere of nitrogen gas.
Sodium amide samples which are yellow or brown in color should be destroyed immediately: one method for destruction is the careful addition of [[ethanol]] to a suspension of sodium amide in a [[hydrocarbon]] solvent.

Sodium amide may be expected to be corrosive to the skin, eyes and mucous membranes. Care should be taken to avoid dispersal of the dust.

==See also==
* [[Lithium amide]]
* [[Sodium bis(trimethylsilyl)amide]]

==References==
<references/>

==External links==
*[http://www.orgsyn.org/orgsyn/default.asp?formgroup=basenp_form_group&dataaction=db&dbname=orgsyn Sodium amide reactions] (from ''[[Organic Syntheses]]'')

{{Sodium compounds}}

[[Category:Sodium compounds]]
[[Category:Amides]]

[[ar:أميد الصوديوم]]
[[de:Natriumamid]]
[[fr:Amidure de sodium]]
[[it:Ammoniuro di sodio]]
[[ja:ナトリウムアミド]]
[[nl:Natriumamide]]
[[pt:Amida de sódio]]
[[ru:Амид натрия]]
[[fi:Natriumamidi]]
[[zh:氨基钠]]

Dimethylglyoxime

2009-08-29T05:11:40Z

Su-no-G: +ja

{{chembox
| ImageFile = Dimethylglyoxime.png
| ImageName = Dimethylglyoxime
| IUPACName = 2,3-Butanedione Dioxime
| OtherNames = Dimethylglyoxime, Diacetyl dioxime, Chugaev's Reagent 2,3-diisonitrosobutane
| Section1 = {{Chembox Identifiers
| CASNo = 95-45-4
| CASNo_Ref = {{cascite}}
| RTECS = EK2975000
}}
| Section2 = {{Chembox Properties
| Formula = C4H8N2O2
| MolarMass = 116.12 g/mol
| Appearance = White/Off White Powder
| Density = 1.37 g/cm3
| Solubility = low
| MeltingPt = 240 - 241 °C (513.15 K)
| BoilingPt = decomp.
}}
| Section3 = {{Chembox Structure
| Dipole = 0
}}
| Section7 = {{Chembox Hazards
| ExternalMSDS = [http://www.sigmaaldrich.com/cgi-bin/hsrun/Suite7/Suite/HAHTpage/Suite.HsSigmaAdvancedSearch.formAction External MSDS]
| MainHazards = Toxic, Skin/Eye Irritant
| NFPA-H = 2
| NFPA-F =
| NFPA-R =
| RPhrases = 20/22
| SPhrases = 22-36/37
}}| Section8 = {{Chembox Related
| OtherCpds = [[Hydroxylamine]], [[salicylaldoxime]]
}}
}}
'''Dimethylglyoxime''' is a [[chemical compound]] described by the formula CH3C(NOH)C(NOH)CH3. This colourless solid is the di[[oxime]] derivative of the diketone [[diacetyl]] (also known as 2,3-butanedione). DmgH2 is used in the analysis of [[palladium]] or [[nickel]]. Its [[coordination complex]]es are of theoretical interest as models for enzymes and as catalysts. Many related ligands can be prepared from other diketones, e.g. [[benzil]].

==Preparation==
Dimethylglyoxime can be prepared from [[butanone]] first by reaction with [[alkyl nitrites|ethylnitrite]] followed by conversion of the biacetyl monoxime using sodium [[hydroxylamine]] monosulfonate:<ref>{{OrgSynth | author = Semon, W. L.; Damerell, V. R. | title = Dimethylglyoxime | collvol = 2 | collvolpages = 204 | year = 1943 | prep = cv2p0204}}</ref>

:[[File:Preparation_of_dimethylglyoxime.png|400px]]

==Ni(dmgH)2==
[[Image:Nidmg.png|left|thumb|Structure of Ni(dmgH)2]]
[[File:Ni(dmg)2.JPG|right|thumb|A sample of Ni(dmgH)2]]
Dimethylglyoxime is used as a [[chelation|chelating agent]] in the [[gravimetric analysis]] of nickel. The use of DMG as a reagent to detect [[nickel]] was discovered by [[Lev Aleksandrovich Chugaev|L. A. Chugaev]] in 1905.<ref>{{cite journal
| title = Über ein neues, empfindliches Reagens auf Nickel
| author = Lev Tschugaeff
| journal = Berichte der deutschen chemischen Gesellschaft
| volume = 38
| issue = 3
| pages = 2520–2522
| year = 1905
| url =
| doi = 10.1002/cber.19050380317 }}</ref> For [[Qualitative inorganic analysis|qualitative analysis]], dmgH2 is often used as a solution in [[ethanol]]. It is the [[conjugate base]], not dmgH2 itself, that forms the complexes. Furthermore, a pair of dmgH- ligands are joined through hydrogen bonds to give a [[macrocycle|macrocyclic ligand]]. The most famous complex is the bright red Ni(dmgH)2, formed by treatment of Ni(II) sources with dmgH2. This planar complex is very poorly soluble and so [[precipitates]] from solution. This method is used for the gravimetric determination of nickel, e.g. in ores.
 

==Cobaloximes==
The nitrogen atoms in dmgH2 and its complexes are sp2 hybridized.<ref>{{cite book | author = Girolami, G.. S.; Rauchfuss, T.B.; Angelici, R. J.| title = Synthesis and Technique in Inorganic Chemistry: A Laboratory Manual | edition = 3rd | date = 1999 | pages = 213–215 }}</ref> Because of the planarity of the resulting ligand, the macrocycle [dmgH]22- resembles some biologically important macrocyclic ligands, as found for example in vitamin B12 and myoglobin. A well known family of model complexes, the cobaloximes, have the formula CoR(dmgH)2L, where R is an [[alkyl]] group and L is typically pyridine. In such complexes, L and R occupy “axial” positions on the cobalt, perpendicular to the plane of the (dmgH)2.

==References==
{{reflist}}

[[Category:Oximes]]
[[Category:Chelating agents]]

[[cs:Diacetyldioxim]]
[[de:Diacetyldioxim]]
[[nl:Dimethylglyoxime]]
[[ja:ジメチルグリオキシム]]
[[pl:Dimetyloglioksym]]
[[ru:Диметилглиоксим]]
[[zh:丁二酮肟]]

Furazan

2009-08-29T04:24:05Z

Su-no-G: +ja

{{chembox
|ImageFile=furazan numbering.png
|ImageSize=120px
|IUPACName=1,2,5-oxadiazole
|OtherNames=
|Section1= {{Chembox Identifiers
| CASNo=288-37-9
| PubChem=67517
| SMILES=C1=NON=C1
}}
|Section2= {{Chembox Properties
| Formula=C2H2N2O
| MolarMass=70.05008
| Appearance=
| Density=
| MeltingPt=
| BoilingPtC= 98
| Solubility=
}}
|Section3= {{Chembox Hazards
| MainHazards=
| FlashPt=
| Autoignition=
}}
}}

'''Furazan''', or 1,2,5-oxadiazole, is an [[heterocyclic compound|heterocyclic]] [[aromaticity|aromatic]] [[organic compound]] with a five-atom ring containing 1 oxygen and 2 nitrogen atoms. Furazan and its derivatives are obtained by heating [[glyoxime]]s ([[dioxime]]s of ortho-[[diketone]]s) with [[alkali]]s or [[ammonia]].

==Derivatives==
3,4-Dimethylfurazan is prepared by heating [[dimethylglyoxime]] with an excess of ammonia for six hours at 165 °C. A liquid at ordinary temperature, it boils at 156 °C. [[Potassium permanganate]] oxidizes it first to methylfurazancarboxylic acid and then to furazandicarboxylic acid. Methylethylfurazan and diphenylfurazan are also known. By warming oxyfurazan acetic acid with excess of potassium permanganate to 100 °C, oxyfurazancarboxylic acid is obtained. It crystallizes in prisms, which melt at 175 °C. Furazancarboxylic acid is prepared by the action of a large excess of potassium permanganate on a hot solution of furazanpropionic acid. It melts at 107 °C, and dissolves in caustic soda, with a deep yellow color and formation of nitrosocyanacetic acid.

The furazan ring system is also found in the steroid [[furazabol]].

==References==
*{{1911}}

[[Category:Nitrogen heterocycles]]
[[Category:Oxygen heterocycles]]

[[ja:フラザン]]
[[lv:Furazāns]]

Isobenzofuran

2009-08-28T15:31:03Z

Su-no-G: +ja

{{chembox
|ImageFile=Isobenzofuran.svg
|ImageSize=150px
|IUPACName=2-Benzofuran
|OtherNames=2-Oxa-2''H''-isoindene; Benzo[''c'']furan
|Section1={{Chembox Identifiers
| CASNo=270-75-7
| PubChem=11378474
| SMILES=C1=CC2=COC=C2C=C1
}}
|Section2={{Chembox Properties
| Formula=C8H6O
| MolarMass=118.13 g/mol
| Appearance=
| Density=
| MeltingPt=
| BoilingPt=
| Solubility=
}}
|Section3={{Chembox Hazards
| MainHazards=
| FlashPt=
| Autoignition=
}}
}}

'''Isobenzofuran''' is a [[heterocyclic compound]] consisting of fused [[benzene]] and [[furan]] rings. It is [[isomer]]ic with [[benzofuran]].

Isobenzofuran is highly reactive and rapidly polymerizes; however, it has been identified<ref>{{cite journal | author = [[Louis Fieser|Fieser, Louis F]] Haddadin Makhluf J.| title = Isobenzofuran, a Transient Intermediate| journal = J. Am. Chem. Soc.| year = 1964 | volume = 86 | issue = 10 | pages = 2081–2 | doi = 10.1021/ja01064a044}}</ref> and prepared by [[thermolysis]] of suitable precursors and trapped at low temperature.<ref>{{cite journal | author = Wege, D | title = Isolation of isobenzofuran | journal = Tetrahedron Letters | year = 1971 | volume = 12 | issue = 25 | pages = 2337–8 | doi = 10.1016/S0040-4039(01)96856-X}}</ref>

Though isobenzofuran itself is not stable, it is the parent of related stable compounds with more complex structures.<ref>''Heterocyclic Chemistry'', J.A. Juole, K. Mills, and G.F. Smith, 3rd Edition, pages 364-365</ref>

==References==
{{reflist}}

[[Category:Benzofurans]]
[[Category:Oxygen heterocycles]]
[[Category:Simple aromatic rings]]

[[fr:Isobenzofurane]]
[[id:Isobenzofuran]]
[[ja:イソベンゾフラン]]

Diazine

2009-08-28T15:01:32Z

Su-no-G: +ja

{{confused|Diazene}}
'''Diazine''' refers to a group of [[organic compound]]s having the [[molecular formula]] C4H4N2. Each contains a [[benzene]] ring in which two of the C-H fragments have been replaced by [[isolobal]] nitrogen. There are three [[isomer]]s: 
* [[pyrazine]] (1,4-diazine) [[image:pyrazine_simple_structure.svg]]
* [[pyrimidine]] (1,3-diazine) [[image:pyrimidine_simple_structure.svg]]
* [[pyridazine]] (1,2-diazine) [[image:pyridazine_simple_structure.svg]]
[[category:simple aromatic rings]]
[[Category:Articles lacking sources (Erik9bot)]]

[[de:Diazine]]
[[es:Diazina]]
[[fr:Diazine]]
[[it:Diazine]]
[[ja:ジアジン]]
[[nl:Diazine]]
[[ru:Диазины]]
[[zh:二嗪]]

Midazolam

2009-08-28T13:43:09Z

Su-no-G: +ja

{{Drugbox|
| IUPAC_name = 8-chloro- 6-(2-fluorophenyl)- 1-methyl- 4H-imidazo[1,5-a] [1,4]benzodiazepine
| image = Midazolam.svg
| width = 140
| image2 = Midazolam3d.png
| image3 = Dormicum.JPG
| image4 = Midazolam.JPG
| CAS_number = 59467-70-8
| ChemSpiderID = 4047
| ATC_prefix = N05
| ATC_suffix = CD08
| ATC_supplemental =
| PubChem = 4192
| DrugBank = APRD00680
| C = 18 | H = 13 | Cl = 1 | F = 1 | N = 3
| molecular_weight = 325.78
| bioavailability = Oral ~36% I.M. 90%+
| metabolism = [[Liver|Hepatic]]
| elimination_half-life = 1.8-6.4 hours
| excretion = [[Kidney|Renal]]
| pregnancy_category = D ([[United States|USA]]) C ([[Australia|Aus]])
| legal_status = [[Schedule IV controlled substance|Schedule IV]](US)
| routes_of_administration = Oral, I.M., I.V., parenteral
}}
'''Midazolam''', pronounced mɪˈdæzəlæm (and marketed in English-speaking countries under brand names '''Dormicum''', '''Hypnovel''', '''Midacum''' and '''Versed''')<ref>{{cite web| url= http://www.non-benzodiazepines.org.uk/benzodiazepine-names.html| title=Benzodiazepine Names| accessdate=2008-12-29| publisher=non-benzodiazepines.org.uk}}</ref> is an ultra short-acting [[benzodiazepine]] [[derivative (chemistry)|derivative]]. It has potent [[anxiolytic]], [[amnestic]]<ref>http://www.mayoclinic.com/health/drug-information/DR600929</ref>, [[hypnotic]], [[anticonvulsant]], [[skeletal muscle relaxant]], and [[sedative]] properties.<ref>{{cite journal |author=Mandrioli R, Mercolini L, Raggi MA |title=Benzodiazepine metabolism: an analytical perspective |journal=Curr. Drug Metab. |volume=9 |issue=8 |pages=827–44 |year=2008 |month=October |pmid=18855614 |doi= 10.2174/138920008786049258|url=http://www.benthamdirect.org/pages/content.php?CDM/2008/00000009/00000008/0009F.SGM}}</ref> Midazolam is water-soluble and fat-soluble in physiologic pH. Freely soluble in alcohol and acetone. It is considered an ultra short-acting benzodiazepine, with an [[elimination half-life]] of about 2 hours. It is used in some countries for the short term treatment of [[insomnia]] and in many countries as a [[premedication]] before surgery.<ref>{{cite journal |author=Kanto JH |title=Midazolam: the first water-soluble benzodiazepine. Pharmacology, pharmacokinetics and efficacy in insomnia and anesthesia |journal=Pharmacotherapy |volume=5 |issue=3 |pages=138–55 |year=1985 |pmid=3161005 |doi= |url=}}</ref> It is therefore a very useful drug to use for short minor procedures such as [[dental extraction]].

Midazolam was first synthesized in 1976 by Fryer and Walser.

==Indications==
Intravenous midazolam is indicated for [[procedural sedation]] (often in combination with an opioid, such as [[fentanyl]]), for pre-op sedation, for the induction of [[general anesthesia]], and for sedation of ventilated patients in critical care units.

Oral midazolam is indicated for the short term treatment of moderately severe insomnia in patients who did not adequately react to other hypnotics, and who have persistent trouble in falling asleep. Because of midazolam's extremely short duration, midazolam is not used for patients who have trouble staying asleep through the night; moderate to long acting benzodiazepines like [[temazepam]], [[nitrazepam]], [[flunitrazepam]] and [[lormetazepam]] are used for those purposes. Like other benzodiazepines, midazolam produces a decrease in delta activity, though the effect of benzodiazepines on delta may not be mediated via benzodiazepine receptors. Delta activity is an indicator of depth of sleep within non-REM sleep; it is thought to reflect sleep quality, with lower levels of delta sleep reflecting poorer sleep. Thus midazolam and other benzodiazepines cause a deterioration in sleep quality. [[Cyproheptadine]] may be superior to [[nitrazepam]] in the treatment of insomnia as it enhances sleep quality based on [[EEG]] studies.<ref>{{cite journal | author = Tokunaga S | coauthors = Takeda Y, Shinomiya K, Hirase M, Kamei C. | year = 2007 | month = February | title = Effects of some H1-antagonists on the sleep-wake cycle in sleep-disturbed rats | journal = J Pharmacol Sci. | volume = 103 | issue = 2 | pages = 201–6 | pmid = 17287588 | url = http://www.jstage.jst.go.jp/article/jphs/103/2/201/_pdf | format = pdf | doi = 10.1254/jphs.FP0061173}}</ref>

Midazolam is also indicated for the acute management of [[aggressive]] or [[delirium|delirious]] patients and also is sometimes used for the acute management of seizures such as [[status epilepticus]]. Long term use for the management of epilepsy is not recommended however, due to the significant risk of tolerance which renders midazolam and other benzodiazepines ineffective and as well the significant side effect of sedation.<ref>{{cite journal | last = Isojärvi | first = JI | coauthors = Tokola RA. | year = 1998 | month = December | title = Benzodiazepines in the treatment of epilepsy in people with intellectual disability | journal = J Intellect Disabil Res. | volume = 42 | issue = 1 | pages = 80–92 | pmid = 10030438 }}</ref>
In mice given chronic midazolam a slowly evolving tolerance developed to the anticonvulsant properties of midazolam over 15 days, although some anticonvulsant effects were still apparent after 15 days of continued administration.<ref>{{cite journal | author = Garratt JC | coauthors = Gent JP, Feely M, Haigh JR. | date = January 5, 1988 | title = Can benzodiazepines be classified by characterising their anticonvulsant tolerance-inducing potential? | journal = Eur J Pharmacol. | volume = 145 | issue = 1 | pages = 75–80 | pmid = 2894998 | doi = 10.1016/0014-2999(88)90351-2}}</ref>

==Availability==
Dormicum brand midazolam is marketed by Roche as white, oval 7.5 mg tablets in boxes of 2 or 3 blisterstrips of 10 tablets, and as blue, oval 15 mg tablets in boxes of 2 blisterstrips of 10 tablets. The tablets are imprinted with "Roche" on one side and the dose of the tablet on the other side.
Dormicum is also available as 1ml, 3ml and 10ml ampoules at a concentration of 5 mg/ml. Another manufacturer, Novell Pharmaceutical Laboratories, makes it available as '''Miloz''' in 3 ml and 5 ml ampoules.

==Side effects==
Residual 'hangover' effects after nighttime administration of midazolam such as sleepiness, impaired psychomotor and [[cognitive]] functions may persist into the next day which may impair the ability of users to drive safely and increase risks of falls and [[hip fractures]].<ref>{{cite journal | author = Vermeeren A. | coauthors = | year = 2004 | month = | title = Residual effects of hypnotics: epidemiology and clinical implications | journal = CNS Drugs. | volume = 18 | issue = 5 | pages = 297–328 | pmid = 15089115 | doi = 10.2165/00023210-200418050-00003 }}</ref> [[Confusion]] and [[amnesia]] are reported with midazolam.<ref>{{cite journal |author=Lieberherr S, Scollo-Lavizzari G, Battegay R |title=[Confusional states following administration of short-acting benzodiazepines (midazolam/triazolam)] |language=German |journal=Schweiz. Rundsch. Med. Prax. |volume=80 |issue=24 |pages=673–5 |year=1991 |month=June |pmid=2068441 |doi= |url=}}</ref>

Midazolam has been known to cause a [[paradoxical reaction]] in susceptible individuals, a well-documented complication with benzodiazapines. When this occurs, the individual may experience anxiety, involuntary movements, aggressive or violent behavior, uncontrollable crying or verbalization, and other similar effects. This seems to be related to the altered state of consciousness or [[disinhibition]] produced by the drug.

Case studies have suggested that this type of negative reaction may be more likely in individuals with a history of psychiatric disorder or substance abuse, though it has also been shown to occur in patients with no such history. This reaction may be linked to use of midazolam in higher doses, among children, or among the elderly. Case studies involving identical twins have demonstrated a possible genetic susceptibility. Paradoxical behavior is often not recalled by the patient due to the amnesia-producing properties of the drug. In extreme situations, [[flumazenil]] can be administered to inhibit or reverse the effects of midazolam. Anti-psychotic medications such as [[haloperidol]] have also been used for this purpose.<ref>{{cite journal |author=Carissa E. Mancuso, Maria G. Tanzi, Michael Gabay |title=[Paradoxical Reactions to Benzodiazepines: Midazolam] [language=English |journal=Pharmacotherapy |year=2004 |url=http://www.medscape.com/viewarticle/489358_6}}</ref>

==Tolerance, dependence and withdrawal==
Midazolam can cause a rapid development of [[drug tolerance]], [[benzodiazepine dependence]] and upon discontinuation a [[benzodiazepine withdrawal syndrome]] can occur, including [[rebound insomnia]]. Gradual reduction of midazolam after regular use can minimise withdrawal and [[rebound effects]]. Tolerance and the resultant withdrawal syndrome may be due to alterations in gene expression which results in long term changes in the function of the GABAergic neuronal system.<ref>{{cite journal |author=Fukuda K, Shoda T, Mima H, Uga H |title=Midazolam induces expression of c-Fos and EGR-1 by a non-GABAergic mechanism |journal=Anesth. Analg. |volume=95 |issue=2 |pages=373–8, table of contents |year=2002 |month=August |pmid=12145054 |doi= 10.1097/00000539-200208000-00024|url=http://www.anesthesia-analgesia.org/cgi/pmidlookup?view=long&pmid=12145054}}</ref><ref>{{cite journal |author=Kales A, Soldatos CR, Bixler EO, Goff PJ, Vela-Bueno A |title=Midazolam: dose-response studies of effectiveness and rebound insomnia |journal=Pharmacology |volume=26 |issue=3 |pages=138–49 |year=1983 |pmid=6132414 |doi= 10.1159/000137795|url=}}</ref><ref>{{cite journal |author=Cho HH, O'Connell JP, Cooney MF, Inchiosa MA |title=Minimizing tolerance and withdrawal to prolonged pediatric sedation: case report and review of the literature |journal=J Intensive Care Med |volume=22 |issue=3 |pages=173–9 |year=2007 |pmid=17569173 |doi= 10.1177/0885066607299556|url=http://jic.sagepub.com/cgi/pmidlookup?view=long&pmid=17569173}}</ref> A study in rats found that midazolam is [[cross tolerant]] with [[barbiturates]] and is able to effectively substitute for barbiturates and suppress barbiturate withdrawal signs.<ref>{{cite journal |author=Yutrzenka GJ, Patrick GA, Rosenberger W |title=Substitution of temazepam and midazolam in pentobarbital-dependent rats |journal=Physiol. Behav. |volume=46 |issue=1 |pages=55–60 |year=1989 |month=July |pmid=2573097 |doi= 10.1016/0031-9384(89)90321-1|url=http://linkinghub.elsevier.com/retrieve/pii/0031-9384(89)90321-1}}</ref>
Patients who are chronic users of benzodiazepine medication who are given midazolam experience reduced therapeutic effects of midazolam, due to tolerance to benzodiazepines.<ref>{{cite journal |author=Potokar J, Coupland N, Wilson S, Rich A, Nutt D |title=Assessment of GABA(A)benzodiazepine receptor (GBzR) sensitivity in patients on benzodiazepines |journal=Psychopharmacology (Berl.) |volume=146 |issue=2 |pages=180–4 |year=1999 |month=September |pmid=10525753 |doi= 10.1007/s002130051104|url=http://link.springer.de/link/service/journals/00213/bibs/9146002/91460180.htm}}</ref>

==Contraindications==
Hypersensitivity, acute narrow angle glaucoma, shock, hypotension, head injury, and drug or alcohol use. Most are relative contraindications.

===Pregnancy===
Midazolam when taken during the [[third trimester]] of pregnancy may cause severe risk to the neonate, including [[benzodiazepine withdrawal syndrome]] with possible symptoms including [[hypotonia]], [[apnoeic]] spells, [[cyanosis]], and impaired [[metabolic]] responses to cold stress. Symptoms of hypotonia and the neonatal benzodiazepine withdrawal syndrome have been reported to persist from hours to months after birth.<ref>{{cite journal | author = McElhatton PR. | coauthors = | year = 1994 | month = Nov-Dec | title = The effects of benzodiazepine use during pregnancy and lactation | journal = Reprod Toxicol. | volume = 8 | issue = 6 | pages = 461–75 | pmid = 7881198 | doi = 10.1016/0890-6238(94)90029-9}}</ref>

==Interactions==
Midazolam is metabolized almost completely by [[CYP3A4|cytochrome P450-3A4]]. [[Grapefruit juice]] reduces intestinal 3A4 and results in less metabolism and higher plasma concentrations, which could result in overdose.

==Mechanism of action==
Like other benzodiazepines, midazolam acts on the benzodiazepine binding site of GABAA receptors. When bound it enhances the binding of [[Gamma-aminobutyric acid|GABA]] to the GABAA receptor which results in inhibitory effects on the [[central nervous system]].<ref>{{cite journal | author = Skerritt JH | coauthors = Johnston GA. | date = May 6, 1983 | title = Enhancement of GABA binding by benzodiazepines and related anxiolytics | journal = Eur J Pharmacol. | volume = 89 | issue = 3-4 | pages = 193–8 | pmid = 6135616 | doi = 10.1016/0014-2999(83)90494-6}}</ref>

==Overdose==
{{See also|Benzodiazepine overdose}}
Symptoms of midazolam overdose include:
*[[Somnolence]] (difficulty staying awake)
*Mental confusion
*[[Hypotension]]
*Impaired motor functions
** Impaired reflexes
** Impaired coordination
** Impaired balance
** Dizziness
*[[Coma]]
*[[Death]]

In animal models, the oral LD50 of midazolam is 825 mg/kg.

Midazolam overdose is considered a medical emergency and generally requires the immediate attention of medical personnel. The [[antidote]] for an overdose of midazolam (or any other benzodiazepine) is [[flumazenil]] (Anexate).
The risk of midazolam overdose is increased significantly if midazolam is abused in conjunction with opiates as was highlighted in a review of deaths of users of the opioid buprenorphine in Singapore.<ref>{{cite journal | last = Lai | first = SH | coauthors = Yao YJ, Lo DS. | year = 2006 | month = October | title = A survey of buprenorphine related deaths in Singapore | journal = Forensic Sci Int. | volume = 162(1-3) | pages = 80–6 | pmid = 16879940 | doi = 10.1016/j.forsciint.2006.03.037 }}</ref>

==Legal status==
In the Netherlands, midazolam is a List II drug of the [[Opium Law]].
Midazolam is a Schedule IV drug under the [[Convention on Psychotropic Substances]].<ref name="ScheduleIV">[http://www.incb.org/pdf/e/list/green.pdf List of psychotropic substances under international control]</ref> In the United Kingdom midazolam is a Schedule III controlled drug.<ref>{{cite web | author = Blackpool NHS Primary Care Trust | title = Medicines Management Update | url = http://www.blackpool.nhs.uk/images/uploads/CD-update-GP-v2-may08.pdf | publisher = [[National Health Service]] | location = United Kingdom | format = PDF | year = 2007}}</ref>

==Law enforcement and criminal justice==
Midazolam is offered to death row inmates before execution in the [[United States]], according to the 1992 film ''[[The Execution Protocol]]''. A [[Missouri]] prison doctor interviewed in the film said virtually no prisoners turned down the drug when it was offered a few hours prior to execution.The doctor also reported to HBO that Versed(R) (midazolam)is about 5 times as potent as Valium(R)(diazepam/Roche)which makes it beneficial for the inmate and staff.

The drug is also used by trained Paramedics to assist in controlling psychotic or mentally disturbed patients.<ref>{{cite news|url=http://www.wsmv.com/news/16844880/detail.html|publisher=WSMV Nashville|title=I-Team: Injection Used To Subdue Prisoners:Medical Expert Says Practice Is Troubling|author=Demetria Kalodimos}}</ref><ref>{{cite news|url=http://blogs.wsj.com/health/2008/07/17/taking-sedatives-to-the-streets/|publisher=The Wall Street Journal Health Blog|title=Taking Sedatives to the Streets|author=Jacob Goldstein}}</ref>

==See also==
*[[Benzodiazepine]]
*[[Benzodiazepine dependence]]
*[[Benzodiazepine withdrawal syndrome]]
*[[Long term effects of benzodiazepines]]
*[[Triazolam]]
*[[Brotizolam]]
*[[Estazolam]]

==Notes==
{{reflist}}

==References==
* [[European Medicines Agency|EMEA]] [http://www.emea.europa.eu/pdfs/human/referral/462002en.pdf Summary of Product Characteristics: Hypnovel and associated names].
* [http://mars.bbraun.de/mars/docman/delivery?contextName=CW_COM_VIEW_CONTEXT&documentId=BPB0000000000000001000001106--000 Clinical Use of Midazolam] by John Shou.
*{{cite journal
| author = Brevoord J, Joosten K, Arts W, van Rooij R, de Hoog M
| title = Status epilepticus: clinical analysis of a treatment protocol based on midazolam and phenytoin
| journal = J Child Neurol
| volume = 20
| issue = 6
| pages = 476–81
| year = 2005
| pmid = 15996395
}}
*{{cite journal
| author = Wolfe T, Macfarlane T
| title = Intranasal midazolam therapy for pediatric status epilepticus
| journal = Am J Emerg Med
| volume = 24
| issue = 3
| pages = 343–6
| year = 2006
| pmid = 16635708
| doi = 10.1016/j.ajem.2005.11.004
}}
*{{cite journal
| author = Johnson T, Rostami-Hodjegan A, Goddard J, Tanner M, Tucker G
| title = Contribution of midazolam and its 1-hydroxy metabolite to preoperative sedation in children: a pharmacokinetic-pharmacodynamic analysis
| journal = Br J Anaesth
| volume = 89
| issue = 3
| pages = 428–37
| year = 2002
| pmid = 12402721
| url = http://bja.oxfordjournals.org/cgi/content/full/89/3/428
| doi = 10.1093/bja/aef213
}}
*''Prediction of the disposition of midazolam in surgical patients by a physiologically based pharmacokinetic model'', Bjorkman, S et al., J Pharm Sci 2001:90(9)1226-1241.
*{{cite journal
| author = Merritt P, Hirshman E, Hsu J, Berrigan M
| title = Metamemory without the memory: are people aware of midazolam-induced amnesia?
| journal = Psychopharmacology (Berl)
| volume = 177
| issue = 3
| pages = 336–43
| year = 2005
| pmid = 15290003
| doi = 10.1007/s00213-004-1958-8
}}

==External links==
*[http://www.pubpk.org/index.php?title=Midazolam PubPK - Midazolam Pharmacokinetics]
*[http://www.rxlist.com/cgi/generic2/versedinj.htm Rx-List - Midazolam (Versed)]
*[http://www.inchem.org/documents/pims/pharm/pim674.htm Inchem - Midazolam]

{{Benzodiazepines}}
{{Anticonvulsants}}
{{Hypnotics and sedatives}}

[[Category:Anticonvulsants]]
[[Category:Anxiolytics]]
[[Category:Benzodiazepines]]
[[Category:Hypnotics]]
[[Category:Imidazoles]]
[[Category:Muscle relaxants]]
[[Category:Sedatives]]

[[de:Midazolam]]
[[es:Midazolam]]
[[eu:Midazolam]]
[[fr:Midazolam]]
[[it:Midazolam]]
[[ja:ミダゾラム]]
[[hu:Midazolam]]
[[nl:Midazolam]]
[[no:Midazolam]]
[[pl:Midazolam]]
[[pt:Midazolam]]
[[ro:Midazolam]]
[[ru:Мидазолам]]
[[fi:Midatsolaami]]
[[sv:Midazolam]]

Quinazoline

2009-08-28T08:43:34Z

Su-no-G: +ja

{{chembox
|ImageFile=Quinazoline numbering.png|
|ImageSize=120px
|IUPACName=Quinazoline
|OtherNames=Benzopyrimidine
|Section1={{Chembox Identifiers
| CASNo=253-82-7
| PubChem=9210
| SMILES=C1=CC=C2C(=C1)C=NC=N2
}}
|Section2={{Chembox Properties
| Formula=C8H6N2
| MolarMass=130.15 g/mol
| Appearance=
| Density=
| MeltingPt=
| BoilingPt=
| Solubility=
}}
|Section3={{Chembox Hazards
| MainHazards=
| FlashPt=
| Autoignition=
}}
}}

'''Quinazoline''' is a compound made up of two fused six-membered [[simple aromatic ring]]s, a [[benzene]] ring and a [[pyrimidine]] ring. Its chemical formula is C8H6N2. Quinazoline is yellow and crystalline. Any derivative of quinazoline may be described as a quinazoline compound.

Medicinally it has been used in various areas especially as an anti-malarial agent and in cancer treatment.
One example of a compound containing the quinazoline structure is [[doxazosin mesylate]].

== See also ==
*[[Quinoxaline]]
*[[Niementowski quinazoline synthesis]]

[[Category:Quinazolines| ]]
[[Category:Nitrogen heterocycles]]
[[Category:Aromatic compounds]]
[[Category:Heterocyclic compounds]]
[[Category:Simple aromatic rings]]
[[Category:Aromatic bases]]
[[Category:Articles lacking sources (Erik9bot)]]

[[de:Chinazolin]]
[[es:Quinazolina]]
[[ja:キナゾリン]]

Propargyl chloride

2009-08-27T11:15:27Z

Su-no-G: +ja

{{chembox
| ImageFile = Propargyl chloride.png
| ImageSize = 100px
| IUPACName = 3-Chloroprop-1-yne
| OtherNames = Propargyl chloride, 3-Chloropropyne, 1-Chloro-2-propyne, 2-Propynyl chloride, Gamma-Chloroallylene, UN 2345
| Section1 = {{Chembox Identifiers
| CASNo = 624-65-7
| EINECS = 210-856-9
| PubChem = 12221
| SMILES = C#CCCl
| InChI = 1/C3H3Cl/c1-2-3-4/h1H,3H2
}}
| Section2 = {{Chembox Properties
| Formula = C3H3Cl
| MolarMass = 74.51 g/mol
| Appearance = Clear to brown liquid
| Density = 1.0306 g/cm³
| MeltingPt = -78 °C
| BoilingPt = 57 °C
| Solubility = Insoluble
}}
| Section3 = {{Chembox Hazards
| MainHazards =
| EUClass = Highly flammable ('''F+'''), highly toxic ('''T+''')
| FlashPt = 18 °C
| Autoignition =
| NFPA-H = 3
| NFPA-F = 3
| NFPA-R = 1
| NFPA-O =
| RPhrases = {{R23/24/25}}, {{R34}}
| SPhrases = {{S16}}, {{S23}}, {{S24/25}}, {{S36/37}}, {{S39}}, {{S45}}
}}
}}

'''Propargyl chloride''', or '''3-chloro-1-[[propyne]]''', is a highly [[toxic]] and [[flammable]] clear brown [[liquid]] with [[chemical formula]] [[Carbon|C]][[Hydrogen|H]][[Carbon|C]][[Carbon|C]][[Hydrogen|H]]2[[Chlorine|Cl]]. It is [[miscible]] with [[benzene]] or [[ethanol]] and [[soluble|insoluble]] in [[water]]. Its refractive index is 1.4350. Common uses for propargyl chloride include [[soil]] fumigation, [[corrosion]] prevention, and as an intermediate in [[organic synthesis]].

It reacts with [[alcohol]]s to form [[propargyl]] [[ether]]s.

== See also ==
* [[Allyl chloride]]
* [[Propargyl]]
* [[Propargyl alcohol]]

==References==
*''Merck Index'', 11th Edition, '''7820'''.

==External links==
* [http://www.chemicalland21.com/specialtychem/finechem/PROPARGYL%20CHLORIDE.htm Entry at chemicalland21.com]

[[Category:Alkynes]]
[[Category:Organochlorides]]

{{organohalide-stub}}
[[ja:塩化プロパルギル]]
[[nl:Propargylchloride]]

Signalling (economics)

2009-08-26T15:08:46Z

Su-no-G: +ja

{{dablink|For the analogous theory in [[evolutionary biology]], see [[signalling theory]]}}

In [[economics]], more precisely in [[contract theory]], '''signalling''' is the idea that one party (termed the ''[[Agent (law)|agent]]'') conveys some meaningful information about itself to another party (the ''[[Principal (commercial law)|principal]]''). For example, in [[Michael Spence|Michael Spence's]] job-market signalling model, (potential) employees send a signal about their ability level to the employer by acquiring certain education credentials. The informational value of the credential comes from the fact that the employer assumes it is positively correlated with having greater ability.

==Introductory questions==
Signaling took root in the idea of [[asymmetric information]] (a deviation from [[perfect information]]), which says that in some economic transactions, inequalities in access to information upset the normal market for the exchange of goods and services. In his seminal 1973 article, [[Michael Spence]] proposed that two parties could get around the problem of asymmetric information by having one party send a '''signal''' that would reveal some piece of relevant information to the other party. That party would then interpret the signal and adjust her purchasing behaviour accordingly — usually by offering a higher price than if she had not received the signal.
There are, of course, many problems that these parties would immediately run into.
* How much time, energy, or money should the sender (''agent'') spend on sending the signal?
* How can the receiver (the ''principal'', who is usually the buyer in the transaction) trust the signal to be an honest declaration of information?
* Assuming there is a '''signaling equilibrium''' under which the sender signals honestly and the receiver trusts that information, under what circumstances will that equilibrium break down?

==A basic job-market signaling model==
In the job market, potential employees seek to sell their services to employers for some [[wage]], or [[price]]. Generally, employers are willing to pay higher wages to employ better workers. While the individual may know his or her own level of ability, the hiring firm is not (usually) able to observe such an intangible trait - thus there is an asymmetry of information between the two parties. Education credentials can be used as a signal to the firm, indicating a certain level of ability that the individual may possess; thereby narrowing the informational gap. This is beneficial to both parties as long as the signal indicates a desirable attribute - a signal such as a criminal record may not be so desirable.

===Assumptions and groundwork===
Spence began his 1973 model with a hypothetical. Suppose that there are two types of employees — good and bad — and that employers are willing to pay a higher wage to the good type than the bad type. Spence assumes that for employers, there's no real way to tell in advance which employees will be of the good or bad type.
Bad employees aren't upset about this, because they get a [[free rider problem|free ride]] from the hard work of the good employees. But good employees know that they deserve to be paid more for their higher productivity, so they desire to invest in the signal — in this case, some amount of [[education]]. Spence assumes that education does not increase the productivity of an individual. But he does make one key assumption: ''good-type employees pay less for one unit of education than bad-type employees''. The cost he refers to is not necessarily the cost of tuition and living expenses, sometimes called out of pocket expenses, as one could make the argument that higher ability persons tend to enroll in "better" (i.e. more expensive) institutions. Rather, the cost Spence is referring to is the [[opportunity cost]]. This is a combination of 'costs', monetary and otherwise, including psychological, time, effort and so on. Of key importance to the value of the signal is the differing cost structure between "good" and "bad" workers. The cost of obtaining identical credentials is strictly lower for the "good" employee than it is for the "bad" employee.

The differing cost structure need not preclude "bad" workers from obtaining the credential. All that is necessary for the signal to have value (informational or otherwise) is that the group with the signal is positively correlated with the previously unobservable group of "good" workers. In general, the degree to which a signal is thought to be correlated to unknown or unobservable attributes is directly related to its value.

===The result===
Spence discovered that even if education did not contribute anything to an employee's productivity, it could still have value to both the employer and employee. If the appropriate cost/benefit structure exists (or is created), "good" employees will buy more education in order to signal their higher productivity.


[[Image:Simple_signalling_framework.PNG]]

The increase in wages associated with obtaining a higher credential is sometimes referred to as the Sheepskin Effect, since "sheepskin" informally denotes a diploma. It is important to note that this is not the same as the returns from an additional year of education. The "sheepskin" effect is actually the wage increase above what would normally be attributed to the extra year of education. This can be observed empirically in the wage differences between 'drop-outs' vs. 'completers' with an equal number of years of education. It is also important that one does not equate the fact that higher wages are paid to more educated individuals entirely to signaling or the 'sheepskin' effects. In reality education serves many different purposes to individuals and society as a whole. Only when all of these aspects, as well as all the many factors affecting wages, are controlled for, does the effect of the "sheepskin" approach its true value. Empirical studies of signalling indicate it as a statistically significant determinant of wages, however it is one of a host of other attributes - age, sex, and geography are examples of other important factors.

One of the consequences of the existence of a pure signaling value to education is that public funding of education, especially higher education, is questioned. The debate is not so much about whether there should be any public funding at all; but what the correct level of funding should be. In purely economic terms, the optimal level of public funding would equal the total public benefits from the educated population - the private value of the signal would be excluded.

==References==
*{{cite journal | author=Michael Spence | title=Job Market Signaling | journal=Quarterly Journal of Economics | volume=87 | issue=3 | year=1973 | pages=355–374 | doi=10.2307/1882010}}

*{{cite journal | author=Michael Spence | title=Signaling in Retrospect and the Informational Structure of Markets | journal=American Economic Review | volume=92 | issue=3 | year=2002 | pages=434–459 | doi=10.1257/00028280260136200}}(also available as his [[Nobel Prize]] [http://nobelprize.org/economics/laureates/2001/spence-lecture.pdf lecture] [[PDF]])

*{{cite journal | author=Andrew Weiss| title=Human Capital vs. Signalling Explanations of Wages | journal=The Journal of Economic Perspectives| volume=9 | issue=4 | year=1995 | pages=133–154}}

==See also==
*[[Countersignaling]]
*[[Impression management]]
*[[Signaling game]]

[[Category:Game theory]]
[[Category:Asymmetric information]]

[[fr:Théorie du signal]]
[[ja:シグナリング]]