An efficient synthesis of 4β and 6α-hydroxylated bile acids

Article abstract of DOI:10.1016/0039-128X(93)90052-O

An efficient method for the preparation of 4β- and 6α-hydroxylated bile acids has been developed.It involved a highly stereoselective acetoxylation at the 4β and 6α 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 α-acetoxy ketones with sodium borohydride or tert-butylamine borane complex, and alkaline hydrolysis, provided the desired bile acids in good yields. Keywords: sterols; bile acid; 4β-hydroxylated bile acid;6α-hydroxylated bile acid; acetoxylation; lead tetraacetate oxidation