Steroidal sulphur compounds. Part IV. Configuration, conformation, and chiroptic properties of 6-alkylsulphinyl-5α-cholestanes

Abstract

The configurations of 18 6-alkylsulphinyl-5α-cholestanes have been determined by the pyrolytic method. Steric considerations were usually more important than statistical factors in deciding the direction of pyrolytic elimination. N.m.r. evidence suggested that their preferred conformations (except for the t-butyl sulphoxides) were similar to those of their methylsulphinyl analogues. The empirical rule relating o.r.d. characteristics with chirality at sulphur in methylsulphinyl alkanes is not generally applicable to 6-alkylsulphinyl-5α-cholestanes. The irregular manner in which their chiroptic properties varied with the nature of the alkyl group could not be attributed to variations in solvational or conformational equilibria.