Highly efficient and selective biocatalytic acylation studies on triazolylsugars

Different acid anhydrides (of C-2 to C-7 aliphatic fatty acids and benzoic acid) have been used to study the selective acylation of primary/secondary hydroxyl groups in 2-phenyl-4-(D-threo-1',2',3'-trihydroxypropyl)-2H-1,2,3-triazole, 2-phenyl-4-(D-erythro-1',2',3'-trihydroxypropyl)-2H-1,2,3-triazole, 2-phenyl-4-(D-arabino-1',2',3,4'-tetrahydroxybutyl)-2H-1,2,3-triazole and 2-phenyl-4-(D-lyxo-1',2',3',4'-tetrahydroxybutyl)-2H-1,2,3-triazole in the presence of Candida antarctica lipase B in diisopropyl ether. Among the different acid anhydrides, butanoic anhydride was found to be the most efficient acylating agent (for butanoylation); for acetylation, vinyl acetate gave the best results. The reactions with both these acylating agents were highly selective and efficient yielding exclusively the monoacylated products in 95-99% yields in 1-5 h. (C) 2003 Elsevier Ltd. All rights reserved.