title: Enzymatic glycosidation of sugar oxazolines having a carboxylate group catalyzed by chitinase.
abstract: Enzymatic glycosidation using sugar oxazolines 1-3 having a carboxylate group as glycosyl donors and compounds 4-6 as glycosyl acceptors was performed by employing a chitinase from Bacillus sp. as catalyst. All the glycosidations proceeded with full control in stereochemistry at the anomeric carbon of the donor and regio-selectivity of the acceptor. The N,N'-diacetyl-6'-O-carboxymethylchitobiose oxazoline derivative 1 was effectively glycosidated, under catalysis by the enzyme, with methyl N,N'-diacetyl-beta-chitobioside (4), pent-4-enyl N-acetyl-beta-D-glucosaminide (5), and methyl N-acetyl-beta-D-glucosaminide (6), affording in good yields the corresponding oligosaccharide derivatives having 6-O-carboxymethyl group at the nonreducing GlcNAc residue. The N,N'-diacetyl-6-O-carboxymethylchitobiose oxazoline derivative 2 was subjected to catalysis by the enzyme catalysis; however, no glycosidated products were produced through the reactions with 4, 5, and 6. Glycosidation reactions of the beta-d-glucosyluronic-(1-->4)-N-acetyl-D-glucosamine oxazoline derivative 3 proceeded with each of the glycosyl acceptors, giving rise to the corresponding oligosaccharide derivative having a GlcA residue at their nonreducing termini in good yields.
authors.affiliation: Department of Materials Chemistry, Graduate School of Engineering, Kyoto University, Kyoto 615-8510, Japan.
authors.forename: Hirofumi
authors.initials: H
authors.lastname: Ochiai
authors.forename: Masashi
authors.initials: M
authors.lastname: Ohmae
authors.forename: Shiro
authors.initials: S
authors.lastname: Kobayashi
mesh_terms: D001407:Bacillus / Q000201:enzymology; D002236:Carbohydrate Conformation; D002240:Carbohydrate Sequence; D002241:Carbohydrates / Q000737:chemistry*; D002264:Carboxylic Acids / Q000737:chemistry*; D002384:Catalysis; D002688:Chitinases / Q000737:chemistry*; D004187:Disaccharides / Q000737:chemistry; D006031:Glycosylation; D008969:Molecular Sequence Data; D010080:Oxazoles / Q000138:chemical synthesis*
chemical_list: D002241:Carbohydrates; D002264:Carboxylic Acids; D004187:Disaccharides; D010080:Oxazoles; D002688:Chitinases