Reactions of the enol sulphite of 3β-acetoxy-5β-hydroxycholestan-6-one

Abstract

Treatment of 3β-acetoxy-5β-hydroxycholestan-6-one (I) with thionyl chloride in pyridine at 0° gave a highly reactive enol sulphite (V), which when chromatographed on aluminium oxide gave 3β-aceloxy-5α,-hydroxy-cholestan-6-one (IVa), 3β-actoxycholest-4-en-6-one (III), and cholesta-2,4-dien-6-one (VI). In 0·1N-hydrochloric acid the enol sulphite gave 3β-acetoxy-5α-hydroxycholestan-6-one, 3β-acetoxycholest-4-en-6-one, and 3β,7α-diacetoxy-5α-cholestan-6-one (VIII). A 1,3-dipolar intermediate is postulated to retionalise these reactions.