Hydroxylation reactions by Udenfriend's system and the related systems were studied on the aqueous solutions of deoxycholic acid (I). No ascorbic acid and EDTA were necessary in the hydroxylation of I. A new bile acid (II), mp 322-325°, was obtained when an aqueous solution of FeSO4·7H2O (54 mmole) was added dropwise to a stirred buffer solution (0.1M Na2HPO4, pH 6.8) of I (2.25 mmole) under bubbling oxygen for 4 hr at 70°. The methyl ester of II gave triketo steroid (V), mp 176-177°, by chromate oxidation and the third oxygen function introduced was found to be situated at C15 as a result of Mass spectrum analysis (Fig. 3). From the smaller effect on the nuclear magnetic resonance signal peak of 18-CH3 (Table II & III), the configuration of C15-OH was concluded to be of alpha. Hydroboration-oxidation of methyl 3α, 12α-dihydroxy-5β-chol-14-en-24-oate (VI) gave the methyl ester of II. The chemical structure of II was thus elucidated as 3α, 12α, 15α-trihydroxy-5β-cholan-24-oic acid.
