Synthesis of Novel Amide-Linked Dimers of Lithocholic Acid

Abstract

An efficient synthesis of lithocholic amides and amide-linked dimers under mild conditions is described. New o-, m- and p-phenylenediamine-derived dimers of lithocholic acid were synthesised by the activation of the carboxyl group of the bile acid as a mixed anhydride resulting from the reaction of the acid with ethyl chloroformate. The reduction of lithocholic amides afforded the corresponding 24-amino-5β-cholane derivatives. All compounds were characterised by IR, 1H and 13C NMR and mass spectra.