The preparation and chemical properties of some glucuronyl esters of β-glycyrrhetic acid (3β-hydroxy-11-oxo-olean-12-en-30-oic acid) and its derivatives

Abstract

The methyl triacetylglucosiduronates of 18β-glycyrrhetic acid and its 3-O-acetyl and 3-oxo-derivatives, and of carbenoxolone (the 3-hemisuccinate of 18β-glycyrrhetic acid) and its 30-methyl and 4′-methyl ester derivatives have been prepared by the condensation of these triterpenoids with methyl triacetylbromoglucuronate in the presence of silver oxide and quinoline, in order to obtain glucuronide conjugates for the identification of metabolites of 18β-glycyrrhetic acid and carbenoxolone. The methyl triacetylglucosiduronates have been hydrolysed with methanolic solutions of trimethylamine to yield 18β-glycyrrhet-30-yl β-glucosiduronic acid and the corresponding carbenoxolone derivative.