| Nitrosobenzene | |
|---|---|
 |
|
| IUPAC name |
Nitrosobenzene
|
| Other names | ? |
| Identifiers | |
| CAS number | 586-96-9 |
| RTECS number | DA6497525 |
| SMILES |
O=Nc1ccccc1
|
| Properties | |
| Molecular formula | C6H5NO |
| Molar mass | 107.11 g/mol |
| Appearance | colourless solid |
| Density | ? g/cm3, ? |
| Melting point |
65-69 °C |
| Boiling point |
59 °C, 18 mm Hg |
| Solubility in water | low |
| Solubility in other solvents | sol. in organic solvents |
| Structure | |
| Molecular shape | N is sp2 |
| Hazards | |
| R-phrases | 20/21-25 |
| S-phrases | 26-36/37-45 |
| Related compounds | |
| Related compounds | Nitrobenzene Aniline |
| Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa) | |
| Infobox references | |
Nitrosobenzene is the organic compound with the formula C6H5NO. The compound can be viewed as hybrid of singlet O2 and azobenzene. This diamagnetic species exists in equilibrium with its dimer.
Contents |
Preparation
C6H5NO was first prepared by Adolf von Baeyer by the reaction of diphenylmercury and nitrosyl bromide:[1]
-
- [C6H5]2Hg + BrNO → C6H5NO + C6H5HgBr
The modern synthesis entails reduction of nitrobenzene to phenylhydroxylamine, C6H5NHOH, which is then oxidized by Na2Cr2O7.[2] C6H5NO can also be prepared by oxidation of aniline using peroxymonosulfuric acid, Caro's acid.[3] It is usually purified by steam distillation, where it comes over as a green liquid that solidifes to a colorless solid.
Characteristic reactions
The monomer undergoes Diels-Alder reactions with dienes.[4] Condensation with anilines affords azobenzene derivatives (Mills reaction)[5]. Reduction of PhNO produces C6H5NH2.
Most characteristically nitrosobenzene condenses with "active" methylene groups, e.g. of malonic esters, benzylcyanide etc. For example, condensation with benzylcyanide PhCH2CN gives the imine PhC(CN)=NPh (The Ehrlich-Sachs Reaction)[6] :
Ph-CH2-CN + Ph-NO => Ph-CH(CN)-N(OH)-Ph (oxyamination adduct) => PhC(CN)=N(OH)Ph
Sometimes condensation with "active" methylene compounds could give products of O-nitroso-aldol reaction [7]:
R-CH2-CHO + Ph-NO => R-CH(CHO)-O-NHPh (aminoxylation adduct)
See also
References
- ^ Baeyer, A. "Nitrosobenzol und Nitrosonaphtalin" Chemische Berichte 1874, volume 7, pp.1638–1640.
- ^ G. H. Coleman, C. M. McCloskey, F. A. Stuart (1955), "Nitrosobenzene", Org. Synth., http://www.orgsyn.org/orgsyn/orgsyn/prepContent.asp?prep=CV3P0668; Coll. Vol. 3: 668
- ^ H. Caro, Z. angew. Chem., volume 11, p 845ff (1898).
- ^ H. Yamamoto, N. Momiyama "Rich Chemistry of Nitroso Compounds" Chemical Communications 2005, pp.3514–3525.
- ^ H. D. Anspon (1955), "p-Phenylazobenzoic Acid", Org. Synth., http://www.orgsyn.org/orgsyn/orgsyn/prepContent.asp?prep=CV3P0711; Coll. Vol. 3: 711
- ^ H. Feuer in S. Patai (ed.) "The Chemistry of the Nitro and Nitroso Groups Part 1," Wiley: New York. pp. 278-283
- ^ Asymmetric O- and N- Nitroso Aldol Reaction - an efficient access to a-oxy and a-amino carbonyl compound
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