The Beckmann rearrangement of 3β-Chloro-5α-cholestan-7-one oxime and related compounds and the Schmidt reaction of the corresponding ketones

Abstract

The chromic acid oxidation of cholesteryl chloride gave 3β- chlorocholest-5-en-7-one, which on hydrogenation gave 3β-chloro-5α- cholestan-7-one. The Schmidt reaction of this ketone afforded a single lactam, 3β-chloro-7a-aza-B-homo-5α-cholestan-7-one. The Beckmann rearrangement of its oxime by means of thionyl chloride or p- toluenesulphonyl chloride and pyridine gave the same lactam. The structure of the lactam was established by its conversion into a known lactam by reduction. 3β-Chlorocholest-5-en-7-one oxime on treatment with thionyl chloride or the corresponding O-tosyloxime on passing through a column of alumina underwent Beckmann rearrangement to give a single lactam, 3β-chloro-7α-aza-B-homocholest-5-en-7-one.