MICROWAVE-INDUCED ORGANIC-REACTIONS OF BILE-ACIDS - ESTERIFICATION DEFORMYLATION AND DEACETYLATION USING MILD REAGENTS

An efficient and convenient procedure for the esterification, deformyl ation, and deacetylation of bile acids is described. This is achieved by the addition of a catalytic amount of methanesulfonic acid or para- toluene sulfonic acid to a solution of bile acid in methanol in the do mestic microwave oven. All these reactions were completed in the micro wave oven within 1-3 min at 60% power (390 W) and the desired bile aci ds, namely trihydroxy-5 beta-cholestanoic acid, (23R)-3 alpha,7 alpha, 23-trihydroxy-5 beta-cholan-24-oic acid, ursocholic acid and 7-ketolit hocholic acid were isolated in 86-94% yield.