Steroids. Part IV. Functionalisation of the 5β-methyl group in derivatives of Westphalen's diol (5-methyl-19-nor-5β-cholest-9-ene-3β,6β-diol)

Abstract

Reaction of three 3β-hydroxy-derivatives of Westphalen's diol with lead tetra-acetate is described. The major products are the ethers 6β-acetoxy-3β,5-oxaethano-19-nor-5β-cholest-9(10)-ene (VIa), 6β-acetoxy-16,16-dibenzyl-3β,5-oxaethano-19-nor-5β-androst-9(10)-17-one (VIb), and 6β-fluoro-3β,5-oxaethano-19-nor-5β-androst-9(10)-en-17-one (VIc) in which the original 5β-methyl group has been functionalised. Oxidation of (VIa) with chromic acid gave products of attack at the 9,10-double bond and/or the allylic position 11. The reduction of (VIa) and subsequent oxidation and boron trifluoride-catalysed cleavage of the tetrahydrofuran ring is described. The configurations of certain compounds were determined from ¹H n.mr. spectra data and the mass spectra of some compounds are briefly discussed.