Reactions of Δ7-steroids. Part III. Conformational transmission effects in the methylation of 5β-cholest-7-en-3-one

Abstract

Methylation of 5β-cholest-7-en-3-one yields 2β-methyl-5β-cholest-7-en-3-one and 2,2-dimethyl-5β-cholest-7-en-3-one. The structure of the former was proven by its conversion into the known 2β-methyl-5β-cholestan-3-one; the structure of the latter was established from the mass spectrum of its ethylene acetal. Use is made of Bucourt's rules of dihedral angle changes in describing the conformational transmission effects which may account for methylation at C-2 rather than at C-4.