Methylsteroids. III. Reduction of ketones derived from lanosterol

Abstract

The base catalysed hydrogen transfer from solvent alcohol to carbonyl groups is studied with 7,ll-dioxolanostan-3β-yl acetate (I ; R=Ac) and shown to give almost entirely 3β,7β,llβ-trihydroxylanostane (V ; R=R'=H) and the epimeric 3β,7-di-hydroxylanostan-11-ones (VI and VIII ; R=H). Generalizations are made to account for their formation and stereochemistry. The four 3β,7,11-trihydrosylanostanes are prepared.