Enzymatic regioselective deprotection of peracetylated mono- and disaccharides

Selective enzymatic hydrolysis of the peracetylated disaccharides, namely c ellobiose, lactose, maltose and melibiose, with lipase from Asperilligus ni ger in aqueous buffer and organic solvent for 30 min afforded exclusively t he corresponding heptaacetates with a free hydroxyl group at C-l in high yi eld. Prolonged reaction of the beta-1,4 linked cellobiose and lactose perac etates afforded selectively their hexaacetates with free hydroxyl groups at C-1,2, whereas the alpha-1,4 linked disaccharides maltose and melibiose pe racetate gave a complex mixture of products. The reaction of 2-acetamido-2- deoxy-1,3,4,6-tetra-O-acetylglucopyranose (11) for 22 h afforded as the maj or product the diacetate 12 with free hydroxyl groups at C-1,4. (C) 1999 El sevier Science B.V. All rights reserved.