Journal of Lipid Research, Vol 26, 1205-1211, Copyright © 1985 by Lipid Research, Inc.
Synthesis of potential cholelitholytic agents: 3 alpha,7 alpha,12 alpha- trihydroxy-7 beta-methyl-5 beta-cholanoic acid, 3 alpha,7 beta,12 alpha- trihydroxy-7 alpha-methyl-5 beta-cholanoic acid, and 3 alpha,12 alpha- dihydroxy-7 xi-methyl-5 beta-cholanoic acid
S Kuroki, M Une and EH Mosbach
This report describes the chemical synthesis of six new bile acid analogs,
namely, 3 alpha,7 alpha,12 alpha-trihydroxy-7 beta-methyl-5 beta-cholanoic
acid (7 beta-methyl-cholic acid), 3 alpha,7 beta,12 alpha-trihydroxy-7
alpha-methyl-5 beta-cholanoic acid (7 alpha-methyl- ursocholic acid), 3
alpha,12 alpha-dihydroxy-7 xi-methyl-5 beta- cholanoic acid (7
xi-methyl-deoxycholic acid), 3 alpha,12 alpha- dihydroxy-7-methyl-5
beta-chol-7-en-24-oic acid, 3 alpha,12 alpha- dihydroxy-7-methyl-5
beta-chol-6-en-24-oic acid, and 3 alpha,12 alpha- dihydroxy-7-methylene-5
beta-cholan-24-oic acid. The carboxyl group of the starting material 3
alpha,12 alpha-dihydroxy-7-oxo-5 beta-cholanoic acid was protected by
conversion to its oxazoline derivative. A Grignard reaction of the bile
acid oxazoline with CH3MgI followed by acid hydrolysis gave two epimeric
trihydroxy-7-methyl-cholanoic acids and three dehydration products. The
latter were purified by silica gel column chromatography and silica
gel-AgNO3 column chromatography of their methyl ester derivatives.
Catalytic hydrogenation of 3 alpha,12 alpha-dihydroxy-7-methyl-5
beta-chol-6-en-24-oic acid and 3 alpha,12 alpha-dihydroxy-7-methylene-5
beta-cholan-24-oic acid gave 3 alpha,12 alpha-dihydroxy-7 xi-methyl-5
beta-cholanoic acid. The configuration of the 7-methyl groups and the
position of the double bonds were assigned by proton nuclear magnetic
resonance spectroscopy and the chromatographic and mass spectrometric
properties of the new compounds. These compounds were synthesized for the
purpose of exploring new and potentially more effective cholelitholytic
agents. The hydrophilic bile acids 7 beta-methyl-cholic acid and 7
alpha-methyl-ursocholic acid are of particular interest because they should
be resistant to bacterial 7- dehydroxylation.