title: Synthesis of 3 alpha, 7 alpha-dihydroxy-5 beta-cholestan-26-oic acid from 3 alpha,7 alpha,12 alpha-trihydroxy-5 beta-cholestan-26-oic acid: configuration in the bile of Alligator mississippiensis.
abstract: Synthesis of 25R- and 25S-diastereoisomers of 3 alpha,7 alpha-dihydroxy-5 beta-cholestan-26-oic acid from 3 alpha,7 alpha,12 alpha-trihydroxy-5 beta-cholestan-26-oic acid is described. The 25S-diastereoisomer of 3 alpha,7 alpha,12 alpha-trihydroxy-5 beta-cholestan- 26-oic acid was obtained by vigorous hydrolysis of the bile of Alligator mississippiensis followed by repeated crystallization of the hydrolysate, and the 25R-diastereoisomer was isolated by hydrolysis of the bile salts in bile of A mississippiensis with rat feces. Acetylation of the 25R- or 25S-diastereoisomer of methyl 3 alpha,7 alpha,12 alpha-trihydroxy-5 beta-cholestan-26-oic acid under controlled conditions yielded the corresponding 3 alpha,7 alpha-diacetate in approximately 70% yield. The diacetate was quantitatively oxidized to methyl 3 alpha,7 alpha-diacetoxy-12-oxo-5 beta-cholestan-26-oate, which was converted into the 12-tosylhydrazone in approximately 58% yield. Reduction of the tosylhydrazone with sodium borohydride in acetic acid yielded the 25R- or the 25S-diastereoisomer of 3 alpha,7 alpha-dihydroxy-5 beta-cholestan-26-oic acid as the major product. Purification via column chromatography yielded the pure diastereoisomers in approximately 25% overall yield. The two diastereoisomers were resolved on thin-layer chromatography and high-performance liquid chromatography. When the bile of A mississippiensis was hydrolyzed with rat fecal bacteria, the 3 alpha,7 alpha-dihydroxy-5 beta-cholestan-26-oic acid isolated via chromatographic purification was shown to be the 25R-diastereoisomer.
authors.affiliation: Department of Medicine, University of Medicine and Dentistry of New Jersey, New Jersey Medical School, Newark.
authors.forename: A K
authors.initials: AK
authors.lastname: Batta
authors.forename: R
authors.initials: R
authors.lastname: Mirchandani
authors.forename: G
authors.initials: G
authors.lastname: Salen
authors.forename: S
authors.initials: S
authors.lastname: Shefer
mesh_terms: D000107:Acetylation; D000489:Alligators and Crocodiles / Q000378:metabolism*; D000818:Animals; D001646:Bile / Q000737:chemistry*; D002777:Cholestanols / Q000138:chemical synthesis* / Q000737:chemistry* / Q000302:isolation & purification; D002851:Chromatography, High Pressure Liquid; D002855:Chromatography, Thin Layer; D008401:Gas Chromatography-Mass Spectrometry; D009682:Magnetic Resonance Spectroscopy; D013237:Stereoisomerism
chemical_list: C000986:3,7-dihydroxycholestan-26-oic acid; D002777:Cholestanols; C022069:3,7,12-trihydroxycholestan-26-oic acid