Molecular conformations. Part III. X-ray analysis of 17aβ-p-bromobenzenesulphonyloxy-17α-methyl-19-nor-9β,10α-D-homoandrost-4-en-3-one

Abstract

The stereochemical course of an unusually facile D-homo rearrangement of 20β-p-bromobenzenesulphonyloxy-19-nor-9β,10α-pregn-4-ene-3-one to 17aβ-p-bromobenzenesulphonyloxy-17α-methyl-19-nor-9β, 10α-D-homoandrost-4-en-3-one has been established by an X-ray crystallographic study. The product molecule is free from major conformational distortion; ring A is in the half-chair form, and rings B, C, and D exhibit chair forms with average valency angles slightly greater than tetrahedral.