By-products in the analysis of β-muricholic acid in biological samples as methyl ester triacetate

Abstract

By-products were formed on analysis of β-muricholic acid (3α,6β, 7β-trihydroxy-5β-cholan-24-oic acid) in biological samples by a method involving acid-catalyzed solvolysis of sulfate esters in acetone-methanol, followed by perchloric acid-catalyzed acetylation with acetic anhydride-acetic acid. These products have been identified by mass spectrometry and nuclear magnetic resonance as methyl 3-0,6-0-diacetyl-7-0-(1-methyl-3-oxo-1-butenyl)- and methyl 3-0,7-0-diacetyl-6-0-(1-methyl-3-oxo-1-butenyl)-β-muricholate, methyl 3-0,6-0-diacetyl- and methyl 3-0, 7-0-diacetyl-β-muricholate, and a methyl diacetoxy-cholen-24-oate.