Lactams

C-alkylated lactams in which the C-alkyl substituent is a primary or secondary alkyl substituent having 1 to 4 carbon atoms is produced by subjecting an organic compound containing a cyclohexyl ring having two tertiary carbon atoms, at least one of which bears a primary or secondary alkyl substituent having from 1 to 4 carbon atoms to the action of a nitrosating agent. The other tertiary carbon atom may be attached to a carboxyl or ketonic group, or 1 to an aliphatic, aromatic-aliphatic, alicyclic, aliphatic-alicyclic, ketonic acid, carbonil, sulphonic acid, sulphinic acid, sulphone, aryl or aroyl radical. The preferred nitrosating agent is nitrosyl sulphuric acid although nitrosyl sulphuric anhydride, nitrosyl chloride, nitrosyl bromide, nitrites, alkyl nitrites, nitrous anhydride or nitrogen monoxide may be used together with chlorosulphonic acid, SO2 and SO3, or SO3 in a nitroparafin. In examples, g - and S -caprolactams are prepared from 4-methyl cyclo hexane carboxylic acid and 2-methyl cyclohexane carboxylic acid respectively. Specifications 904,302, 904,413, 912,034, 922,273, 949,383 and 957,676 are referred to.