Bile acids. LXIV. Synthesis of 5 alpha-cholestane-3 alpha, 7 alpha, 25-triol and esters of new 5 alpha-bile acids.

Interest in the structural requirements of a sterol or bile acid for maximal activity by an hepatic microsomal steroid 12 alpha-hydroxylase prompted the preparation of 5 alpha-cholestane-3 alpha, 7 alpha, 25-triol and 5 alpha-analogs of 3 alpha, 7 alpha-dihydroxy-5 beta-cholane-24-carboxylic acid. Methyl 3 alpha, 7 alpha-dihydroxy-5 beta-cholane-24-carboxylate derived from methyl chenodeoxycholate via the Arndt-Eistert reaction was allomerized with Raney nickel in boiling p-cymene to provide a number of product of which methyl 3, 7-dioxo-5 beta- and 5 alpha-cholane-24-carboxylates, methyl 3-oxo-7 alpha-hydroxy-5 beta-and 5 alpha-cholane-24-carboxylates, were identified. Reduction with K-Selectride of methyl 3-oxo-7 alpha-hydroxy-5 beta-cholane-24-carboxylate, provided a high yield of methyl 3 alpha, 7 alpha-dihydroxy-5 alpha-cholane-24-carboxylate. Treatment of this ester with an excess of methyl magnesium iodide afforded 5 alpha-cholestane-3 alpha, 7 alpha, 25-triol. The products were characterized by thin-layer and gas liquid chromatography, proton resonance, infrared and mass spectrometry.