Transformed steroids. 189. Synthesis and transformations of 21-hydroxy-5α-H-pregnane 2′,2′-dimethyl-[16α,17α-d]-thioxalanes

In a continuation of the research on use of 20-keto-16α,17α-epoxysteroid 20-hydrazones for synthesis of 17-thio analogs of 20-ketosteroid 16α,17α-acetonides [2, 3], we synthesized 5α-H-pregnane-3β,16α,21-trihydroxy-17α-thiol-20-one 16,17-acetonide and found methods for its microbiological dehydrogenation and hydroxylation into Δ4-3-keto-and 9α-hydroxy-Δ4-3-keto derivatives.