Pharmaceutical Institute, Tohoku University, Aobayama, Sendai 980, Japan
Hoshi College of Pharmacy, Ebara 2-4-41, Shinagawa-ku, Tokyo 142, Japan
Abstract:
An efficient synthesis of 3β-hydroxy-5-cholanic acid (8) and 3β-hydroxy-Δ5-cholanic acid (16) was carried out starting from 5-dihydropregnenolene (1) and pregnenolone (9). The monoacetates (3 and 11), prepared by Grignard reaction of 1 and 9 with 3,3-ethylenedioxypropylmagnesium bromide followed by acetylation, were dehydrated selectively to give the Δ20(22)-compounds (4 and 12) which on hydrogenation followed by acid treatment and Jones oxidation yielded 8 and 16, respectively.