Steroids 1993-02-01

An efficient synthesis of 4 beta- and 6 alpha-hydroxylated bile acids.

T Yoshimura, R Mahara, T Kurosawa, S Ikegawa, M Tohma

Index: Steroids 58(2) , 52-8, (1993)

Full Text: HTML

Abstract

An efficient method for the preparation of 4 beta- and 6 alpha-hydroxylated bile acids has been developed. It involved a highly stereoselective acetoxylation at the 4 beta and 6 alpha positions of 3- and 7-oxo bile acids, respectively, with lead tetraacetate in the presence of boron trifluoride etherate in acetic acid. Reduction of the resulting alpha-acetoxy ketones with sodium borohydride or tert-butylamine borane complex, and alkaline hydrolysis, provided the desired bile acids in good yields.