The synthesis of some 32-functionalised lanostane derivatives

Abstract

Lanosterol has been converted into 3β-acetoxylanost-7-en-32-onitrile and thence into 3β-acetoxylanost-7-en-32-al and 3β,32-diacetoxylanost-7-ene. 3β-Acetoxy-11-oxolanost-8-en-32-onitrile and methyl 3β-acetoxy-32-nitrilo-11-oxo-25,26,27-trinorlanost-8-en-24-oate have been synthesised by an analogous route. Unsuccessful attempts to prepare 3β-acetoxylanost-7-en-32-oic acid are reported, together with some novel methods for the oxidation of sterically hindered aldehydes as exemplified by using pivalaldehyde as a model compound.