Enzymatic syntheses of L-valyl, L-leucyl and L-isoleucyl esters of carbohydrates using Candida rugosa lipase

Abstract

L-Valyl 1 L-leucyl 2 and L-isoleucyl 3 esters of carbohydrates 4-14 have been prepared through lipase catalysis using Candida rugosa lipase in organic media. This enzymatic esterification involving unprotected and unactivated L-amino acids 1-3 and carbohydrates, comprising, aldohexoses 4-6, ketohexose 7, pentoses 8-9, disaccharides 10-12 and carbohydrate alcohols 13-14, results in the formation of both monoesters (1-O-, 2-O-, 3-O-, 4-O, 5-O-, 6-O- and 6'-O-) and diesters (1,6-di-O-, 2,5-di-O-, 2,6-di-O-, 3,6-di-O-, 4,6-di-O- and 6,6’-di-O-) with conversion yields in the range 21-68%. Among 70 esters synthesized on the whole, 65 esters are reported here for the first time.