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

2,3-Dichloro-5,6-dicyano-1,4-benzoquinone
"DDQ" redirects here. DDQ is also the former callsign of a TV station in Toowoomba, Australia.
2,3-Dichloro-5,6-dicyano-1,4-benzoquinone[1]
Identifiers
Abbreviations DDQ
CAS number 84-58-2 YesY
PubChem 6775
ChemSpider 6517 YesY
EC number 201-542-2
RTECS number GU4825000
Jmol-3D images Image 1
Properties
Molecular formula C8Cl2N2O2
Molar mass 227 g mol−1
Appearance yellow to orange powder
Density 1.7g/cm3
Melting point

210-215 °C (dec.)

Boiling point

301.8°C @ 760mmHg

Solubility in water reacts
Hazards
R-phrases R25 R29
S-phrases S22 S24/25 S37 S45
Flash point 136.3°C
 YesY (verify) (what is: YesY/N?)
Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa)
Infobox references

2,3-Dichloro-5,6-dicyano-1,4-benzoquinone (or DDQ) is the chemical reagent with formula C8Cl2N2O2. This oxidant is useful for the dehydrogenation of alcohols[2], phenols[3] and steroid ketones[4] in organic chemistry. DDQ decomposes in water, but is stable in aqueous mineral acid.

Contents

Preparation

Synthesis of DDQ involves in cyanation and chlorination of benzoquinone. Thiele and Günther first reported a 6-step preparation in 1906[5]. A single-step chlorination from 2,3-dicyanohydroquinone was reported by Walker and Waugh in 1965.[2]

Stability

DDQ can react with water and give off hydrogen cyanide (HCN), which is highly toxic. Storage should be in dry area. Low temperature and weak acid environment can increase the stability of DDQ.

Uses

It is reagent used in organic chemistry as mild oxidizing agent and a radical receptor.

Reactions

1.Dehydrogenation

DDQ-dehydrogenation.png

2.Aromatization

DDQ-aromatization.png[6]

3.Oxidative Coupling

DDQ-oxi-coupling1.png
DDQ-oxi-coupling2.png [7]

References

  1. ^ 2,3-Dichloro-5,6-dicyano-p-benzoquinone at Sigma-Aldrich
  2. ^ a b Braude. E.A,, Linstead, R. P., and Wooldridge, K. R. H. (Aug 1956). "Hydrogen Transfer. 9. The selective dehydrogenation of unsaturated alcohols by high-potential quinones". Journal of the American Chemical Society: 3070–3074. doi:10.1039/JR9560003070. 
  3. ^ Becker. H.D, (1965). "Quinone Dehydrogenation .I. Oxidation Of Monohydric Phenols". Journal of Organic Chemistry 30 (4): 982. doi:10.1021/jo01015a006. 
  4. ^ A.B. Turner, H.J Ringold (1967). "Applications of high-potential quinones. Part I. The mechanism of dehydrogenation of steroidal ketones by 2,3-dichloro-5,6-dicyanobenzoquinone". Journal of the Chemical Society: 1720–1730. doi:10.1039/J39670001720. 
  5. ^ Thiele, J., and Gunther (1906). Ann. 
  6. ^ Brown.W, Turner. AB; Turner, A. B. (1971). "Application of High-potential Quinones. 7. Synthesis of steroidal phenanthrenes by double methyl migration". J. Chem. Soc. C. (14): 2566–2572. doi:10.1039/J39710002566. 
  7. ^ YH.Zhang, CJ. Li, and Wooldridge, K. R. H. (2006). "DDQ-Mediated Direct Cross-Dehydrogenative-Coupling (CDC) between Benzyl Ethers and Simple Ketones". Journal of the American Chemical Society 128 (13): 4242–4243. doi:10.1021/ja060050p. 

External links