The Nef reaction is the reaction of acid hydrolysis of nitro compounds to form carbonyl compounds . It was discovered in 1892 by the Russian chemist M. I. Konovalov and J. Nef in 1894.
Mechanism
The Nef reaction consists in the hydrolysis of acyl forms of nitro compounds (nitron acids), and therefore primary and secondary aliphatic and alicyclic nitro compounds can enter it.
At the first stage, the nitro compound interacts with aqueous or alcoholic solutions of bases ( sodium hydroxide, sodium methanolate , dimethylamine ), passing into the tautomeric acyl form:
Then, the resulting compound is added to a solution of mineral acid ( sulfuric or hydrochloric ) with nucleophilic addition of a water molecule and the subsequent removal of the nitro group in the form of nitric oxide (I) :
General reaction scheme:
The Nef reaction allows to obtain carbonyl compounds with a yield of up to 80-85%. To do this, the reaction is carried out at pH = 0.1-1, since in a less acidic environment nitronic acids are isomerized back to the nitro compound with a decrease in the conversion of the nitro compound, and in a more acidic environment, the formation of by-products ( oximes , hydroxamic and carboxylic acids ) increases.
The Nef reaction is used for the preparative synthesis of aldehydes and ketones containing other functional groups.
Literature
- Chemical Encyclopedia / Editorial Board: Knunyants I.L. et al. - M .: Soviet Encyclopedia, 1992. - T. 3 (Med-Paul). - 639 p. - ISBN 5-82270-039-8 .
- J.J. Lee. Named reactions. Organic Reaction Mechanisms = Jie Jack Lee - Name Reacions. - M .: BINOM. Laboratory of Knowledge, 2006. - 456 p. - 2000 copies. - ISBN 5-94774-368-X .