RESUMO
A synthesis of /23R and 23S/-3 alpha, 7 alpha, 23-trihydroxy-5 beta-cholan-24-oic acids is described. Lithium enolate of completely protected starting chenodeoxycholic acid was directly hydroxylated at C-23 by the oxidoperoxymolybdenum /hexamethylphosphoric triamide/ /pyridine/ complex. The resulting derivatives containing hydroxyl group at C-23 were separated by liquid column chromatography and their configurations at C-23 were assigned by molecular rotation as well as circular dichroism measurements. In a similar way /23R and 23S/-3 alpha, 7 alpha, 12 alpha, 23-tetrahydroxy-5 beta-cholan-24-oic acids were prepared and their structures identified. Synthetic compounds of the 23R configuration proved to be identical with the bile acids previously isolated from seal bile.
