Comparative studies of ‘bile salts’. 11. 3α:6α:12α-Trihydroxycholanic acid and related substances

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Abstract
Care-ful alkaline hydrolysis of ethyl 3[alpha], 7[alpha]-diacetoxy-6[alpha] -bromo-7-oxocholanate has given, after appropriate further treatment, methyl 3[alpha], 6[alpha], 12[alpha]-tri-acetoxy-7-oxocholanate and an isomer, probably methyl 3[alpha], 6[beta], 12[alpha]-triacetoxy-7-oxocholanate. The thio ketal of the 6[alpha]-compound with Raney nickel gave derivatives of deoxycholic acid, and, in minor yield, of 3[alpha], 6[alpha], 12[alpha]-trihydroxycholanic acid. This last acid has been converted into hyodeoxycholic acid. These results confirm and extend those of Takeda, K. and Igarashi, K. (1956). J. Pharm. Soc. Japan, 76, 867. There is no doubt that 3[alpha], 6[alpha], 12[alpha]-trihydroxycholanic acid is not the substance ("3, 6, 12-trihydroxycholanic acid") obtained by Ohta, K. (1939). Hoppe-Seyl. Z. 259, 53, from "tetrahydroxynorsterocholanic acid". The enol acetate of ethyl 3[alpha], 12[alpha]-diacetoxy-7-oxocholanate has been prepared and treated with perbenzoic acid. Hydrolysis of the epoxide gave, in fair yield, an acid C24H38O6 which in Kishner-Wolff condition was converted into two other acids, C24H40O6 and (probably) 024H3805. The chemical reactions of these substances have been explored, and it is suggested that a possible formula for the acid C24H38O5 is (X). Crystalline diacetyl ethyl hypo-cholate ([alpha])D + 23[degree] has been converted into ethyl 3[alpha], 6[alpha]-diacetoxy-7-oxocholanate,([alpha]) D+ 25". Hot alkaline hydrolysis of this gave, after purification, a new preparation of "acid A" (Haslewood, G.A.D. (1956). Biochem. J. 62, 637), m.p. 226-227[degree], ([alpha])D + 35[degree]. Hence, as Ziegler, P. (1956b). Canad. J. Chem. 34, 1528) suggested, the original "acid A" was impure. It could not have been chiefly 3[alpha], 6[alpha]-dihydroxy-7-oxocho-lanic acid.