TRANSFORMED STEROIDS .20. DIRECTION OF OXIDE CYCLE OPENING OF STEREOISOMERIC 16,17-OXIDES OF DEHYDROPREGNENOLONE 20-HYDRAZONE

Opening of the oxide cycle in stereoisomeric 16,17-oxides of dehydropregnenolone caused by the action of acetic acid in the presence of diphenylhydrazine is strictly selective and takes place at C(17) only. With the 16α,17α-oxide cis-opening is the case and results in 16α-acetoxy-3β,17α-dihydroxypregn-5-en-20-one, whereas the 16β,17β-oxide involves a 16 → 17 hydride shift and leads to 3β-hydroxypregn-5-en-16,20-dione. These results corroborate the mechanism of the reaction described as a reversible electronic shift in the hydrazone fragment of the side chain. © 1969.