Synthesis of N-acetylglucosaminides of unconjugated and conjugated bile acids

Article abstract of DOI:10.1016/0039-128X(92)90021-Z

3-N-Acetylglucosaminides of unconjugated, glycine- and taurine-conjugated bile acids have been synthesized.Bile acids appropriately protected were condensed with acetochloroglucosamine through the 3α-hydroxyl group by means of the Koenigs-Knorr reaction using cadmium carbonate as a catalyst.Subsequent borohydride reduction and/or alkaline hydrolysis provided desired 3-N-acetylglucosaminides of unconjugated bile acids.Glycine-conjugates were obtained from N-acetylglucosaminides of unconjugated bile acids and ethyl glycinate by the carbodiimide method.The preparation of N-acetylglucosaminides of taurine-conjugates was attained by the Koenigs-Knorr reaction of bile acid p-nitrophenyl esters followed by condensation with taurine. 7-N-Acetylglucosaminides of ursodeoxycholates were prepared in a similar fashion.The convenient synthesis of 3-N-acetylglucosaminides of unconjugated bile acids is also described.Keywords: bile acids; N-acetylglucosaminide; glycine-conjugate; taurine-conjugate; Koenigs-Knorr reaction; p-nitrophenyl ester method