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

{{Redirect|DDQ|the Australian television station|RTQ}} {{Chembox |Watchedfields = changed |verifiedrevid = 477190823 |Reference =<ref>[https://www.sigmaaldrich.com/US/en/product/aldrich/d60400 2,3-Dichloro-5,6-dicyano-''p''-benzoquinone] at Sigma-Aldrich</ref> |ImageFileL1 = Dichlorodicyanobenzoquinone.svg |ImageSizeL1 = 120 |ImageAltL1 = Structural formula of dichlorodicyanobenzoquinone |ImageFileR1 = Dichlorodicyanobenzoquinone 3D spacefill.png |ImageSizeR1 = 130 |ImageAltR1 = Space-filling model of the dichlorodicyanobenzoquinone molecule |ImageFile2= DDQpowder.jpg |PIN = 4,5-Dichloro-3,6-dioxocyclohexa-1,4-diene-1,2-dicarbonitrile<ref name=iupac2013>{{cite book | title = Nomenclature of Organic Chemistry : IUPAC Recommendations and Preferred Names 2013 (Blue Book) | publisher = The Royal Society of Chemistry | date = 2014 | location = Cambridge | page = 50 | doi = 10.1039/9781849733069-FP001 | isbn = 978-0-85404-182-4}}</ref> |OtherNames = {{unbulleted list |2,3-Dichloro-5,6-dicyano-''p''-benzoquinone |4,5-Dichloro-3,6-dioxo-1,4-cyclohexadiene-1,2-dicarbonitrile |Dichlorodicyanobenzoquinone}} |Section1={{Chembox Identifiers |Abbreviations = DDQ |ChemSpiderID_Ref = {{chemspidercite|correct|chemspider}} |ChemSpiderID = 6517 |InChI = 1/C8Cl2N2O2/c9-5-6(10)8(14)4(2-12)3(1-11)7(5)13 |InChIKey = HZNVUJQVZSTENZ-UHFFFAOYAL |StdInChI_Ref = {{stdinchicite|correct|chemspider}} |StdInChI = 1S/C8Cl2N2O2/c9-5-6(10)8(14)4(2-12)3(1-11)7(5)13 |StdInChIKey_Ref = {{stdinchicite|correct|chemspider}} |StdInChIKey = HZNVUJQVZSTENZ-UHFFFAOYSA-N |CASNo_Ref = {{cascite|correct|CAS}} |CASNo = 84-58-2 |UNII_Ref = {{fdacite|correct|FDA}} |UNII = 1H5KD39UH7 |PubChem =6775 |RTECS = GU4825000 |EINECS = 201-542-2 |SMILES = ClC=1C(=O)C(\C#N)=C(\C#N)C(=O)C=1Cl }} |Section2={{Chembox Properties |C=8 | Cl=2 | N=2 | O=2 |Appearance = yellow to orange powder |Density = 1.7g/cm3 |MeltingPtC = 210 - 215 |MeltingPt_notes = (decomposes) |BoilingPtC = 301.8 |BoilingPt_notes = at 760mmHg |Solubility = reacts}} |Section3={{Chembox Hazards |FlashPtC = 136.3 |GHSPictograms = {{GHS06}} |GHSSignalWord = Danger |HPhrases = {{H-phrases|301}} |PPhrases = {{P-phrases|264|270|301+310|321|330|405|501}} }} }}

'''2,3-Dichloro-5,6-dicyano-1,4-benzoquinone''' (or '''DDQ''') is the chemical reagent with formula C₆Cl₂(CN)₂O₂. This oxidant is useful for the dehydrogenation of alcohols,<ref name="Braude 1956">{{cite journal | journal = Journal of the Chemical Society (Resumed) |author1=Braude, E. A. |author2=Linstead, R. P. |author3=Wooldridge, K. R. H. | title = 593. Hydrogen Transfer. Part IX The Selective Dehydrogenation of Unsaturated Alcohols by High-potential Quinones | year = 1956 | volume = 1956 | pages = 3070–3074 | doi = 10.1039/JR9560003070}}</ref> phenols,<ref>{{cite journal | author = Becker, H. D. | title = Quinone Dehydrogenation. I. Oxidation of Monohydric Phenols | journal = Journal of Organic Chemistry | year = 1965 | volume = 30 | issue = 4 | pages = 982–989 | doi = 10.1021/jo01015a006 }}</ref> and steroid ketones.<ref>{{cite journal|author1=Turner, A. B. |author2=Ringold, H. J. | title = Applications of High-potential Quinones. Part I. The Mechanism of Dehydrogenation of Steroidal Ketones by 2,3-Dichloro-5,6-Dicyanobenzoquinone | journal = Journal of the Chemical Society C: Organic | year = 1967 | volume = 1967 | pages = 1720–1730 | doi = 10.1039/J39670001720}}</ref> DDQ decomposes in water, but is stable in aqueous mineral acid.<ref name=EROS>{{cite encyclopedia|first1=Derek R.|last1=Buckle|first2=Steven J.|last2=Collier|first3=Mark D.|last3=McLaws|title=2,3-Dichloro-5,6-dicyano-1,4-benzoquinone|encyclopedia=e-EROS Encyclopedia of Reagents for Organic Synthesis|year= 2005|doi= 10.1002/047084289X.rd114.pub2|isbn=0471936235 }}</ref>

==Preparation== Synthesis of DDQ involves cyanation of chloranil. J. Thiele and F. Günther first reported a 6-step preparation in 1906.<ref>{{cite journal | journal = Justus Liebig's Annalen der Chemie |author1=Thiele, J. |author2=Günther, F. | title = Ueber Abkömmlinge des Dicyanhydrochinons | year = 1906 | volume = 349 | issue = 1 | pages = 45–66 | doi = 10.1002/jlac.19063490103 |url=https://zenodo.org/record/1427563}}</ref> The substance did not receive interest until its potential as a dehydrogenation agent was discovered. A single-step chlorination from 2,3-dicyanohydroquinone was reported in 1965.<ref>{{ cite journal |author1=Walker, D. |author2=Waugh, T. D. | title = 2,3-Dichloro-5,6-Dicyanobenzoquinone (DDQ). A New Preparation | journal = The Journal of Organic Chemistry | year = 1965 | volume = 30 | issue = 9 | pages = 3240 | doi = 10.1021/jo01020a529}}</ref>

==Reactions== The reagent removes pairs of H atoms from organic molecules. The stoichiometry of its action is illustrated by the conversion of tetralin to naphthalene: :2 C₆Cl₂(CN)₂O₂ + C₁₀H₁₂ → 2 C₆Cl₂(CN)₂(OH)₂ + C₁₀H₈

The resulting hydroquinone is poorly soluble in typical reaction solvents (dioxane, benzene, alkanes), which facilitates workup.

Solutions of DDQ in benzene are red, due to the formation of a charge-transfer complex.<ref>{{Citation|last1=Rathore|first1=Rajendra|title=Donor/acceptor organizations and the electron-transfer paradigm for organic reactivity|date=2000|work=Advances in Physical Organic Chemistry|pages=193–318|publisher=Elsevier|doi=10.1016/s0065-3160(00)35014-6|isbn=9780120335350|last2=Kochi|first2=Jay K.}}</ref>

===Dehydrogenation=== :400px

===Aromatization=== :400px<ref>{{ cite journal |author1=Brown, W. |author2=Turner, A. B. | title = Application of High-potential Quinones. 7. Synthesis of Steroidal Phenanthrenes by Double Methyl Migration | journal = Journal of the Chemical Society C: Organic | year = 1971 | volume = 1971 | pages = 2566–2572 | doi = 10.1039/J39710002566 |pmid=5167256}}</ref>

===Cross-Dehydrogenative Coupling=== :400px :<ref>{{ cite journal |author1=Zhang, Y. |author2=Li, C. J. | title = DDQ-Mediated Direct Cross-Dehydrogenative-Coupling (CDC) between Benzyl Ethers and Simple Ketones | journal = Journal of the American Chemical Society | year = 2006 | volume = 128 | issue = 13 | pages = 4242–4243 | doi = 10.1021/ja060050p |pmid=16568995|bibcode=2006JAChS.128.4242Z }}</ref>

==Safety== DDQ reacts with water to release highly toxic hydrogen cyanide (HCN).<ref name=EROS/>

==References== {{Reflist}}

==External links== * [https://web.archive.org/web/20100512234642/http://hplusmagazine.com/articles/ai/%E2%80%9C-neurons-brain%E2%80%9D-molecular-computer-evolves "Like Neurons in the Brain": A Molecular Computer that Evolves]

{{DEFAULTSORT:Dichloro-5, 6-Dicyano-1, 4-Benzoquinone, 2, 3-}} Category:Nitriles Category:Chlorobenzene compounds Category:1,4-Benzoquinones Category:Oxidizing agents Category:Reagents for organic chemistry