Glucuronidation of Two Novel Metabolites of Benproperine with Trichloroacetimidate Donor1

The glucuronide metabolites of benproperine were synthesized from mono-hydroxylate metabolites of benproperine that were treated with methyl(2,3,4-tri-O-acetyl-l-O-trichloroacetimidoyl)-α-D-glucopyranurone with BF3 · Et2O as the promoter followed by basic hydrolyzation with Na2CO3. The form of basic acceptors, the order of addition, and the promoter are all important variables in this glucuronidation. The salt form of the basic acceptor was found to be better than its free form for glucuronidation with a Lewis acid as the promoter. Two mono-hydroxylated benproperines were synthesized from 2-benzylphenol in three steps.