Comparative studies of ‘bile salts’. 9. The isolation and chemistry of hyocholic acid

Abstract

Hyocholic acid, C24H40O5, from pig bile was shown to be 3 alpha: 6 alpha: 7-trihydroxycholanic acid (II); the hydroxyl group at C-7 is probably alpha-orientated. This substance appears to be the first authentic example of a 6:7-dihydroxycholane: the presence of the hydroxyl group at C-6 in this cholane derivative causes marked hindrance in the reactions of the C-7 hydroxyl group and of the ketone derived from it. Pig bile contains at least one unidentified substance, giving a spot on paper chromatograms of the ethylated "bile acids." Attention is drawn to the remarkable chemical nature of pig bile salts, and it is suggested that this unique nature must be taken into consideration in studies of pig evolution.