title: Synthesis of 2-methyl-[2-acetamido-4-O-acetyl-6-O-benzyl-3-O-(2-butenyl)-1,2-dideoxy-alpha-D -glucopyrano]-[2,1-d]-2-oxazoline, a versatile intermediate for the synthesis of complex oligosaccharides of bacterial cell-wall, human milk, and blood-group substances.
abstract: 2-Methyl-[2-acetamido-4-O-acetyl-6-O-benzyl-3-O-(2-butenyl)-1,2-dideoxy-alpha-D-glucopyrano]-[2,1-d]-2-oxazoline (2), a glycosylating agent in which the three hydroxyl groups are blocked with protecting groups of differing "persistence", is of utility in the synthesis of oligosaccharides containing highly branched 2-acetamido-2-deoxy-D-glucosyl residues, and it was synthesized in a ten-step sequence from 2-acetamido-2-deoxy-D-glucose via allyl 2-acetamido-4,6-O-benzylidene-2-deoxy-beta-D-glucopyranoside (3). Alkylation of 3 with 2-butenyl (crotyl) bromide, hydrolysis of the benzylidene acetal group, benzylation of the 6-hydroxyl group, and acetylation of the 4-hydroxyl group afforded allyl 2-acetamido-4-O-acetyl-6-O-benzyl-3-O-(2-butenyl)-2-deoxy-beta-D-glucopyranoside(10). Treatment of 10 with chlorotris(tri-phenylphosphine)rhodium(I) gave mainly the corresponding 1-propenyl beta-glycoside, which was converted into oxazoline 2 by the action of mercuric chloride-mercuric oxide in acetonitrile. Glycosylation of benzyl 2-acetamido-3,6-di-O-benzyl-2-deoxy-alpha-D-glucopyranoside with 2, and subsequent O-deacetylation at O-4' gave a glycosyl acceptor, benzyl 2-acetamido-4-O-[2-acetamido-6-O-benzyl-3-O-(2-butenyl) -2-deoxy-beta-D-glucopyranosyl]-3,6-di-O-benzyl-2-deoxy-alpha-D-glucopyranoside .
mesh_terms: D000117:Acetylglucosamine / Q000031:analogs & derivatives* / Q000138:chemical synthesis; D001419:Bacteria / Q000276:immunology; D001789:Blood Group Antigens; D002236:Carbohydrate Conformation; D002473:Cell Wall / Q000276:immunology*; D005260:Female; D005944:Glucosamine / Q000031:analogs & derivatives*; D006801:Humans; D007202:Indicators and Reagents; D009682:Magnetic Resonance Spectroscopy; D008722:Methods; D008895:Milk, Human / Q000276:immunology*; D009844:Oligosaccharides / Q000138:chemical synthesis*; D011247:Pregnancy; D013329:Structure-Activity Relationship
chemical_list: D001789:Blood Group Antigens; D007202:Indicators and Reagents; D009844:Oligosaccharides; C030146:2-methyl-(2-acetamido-4-O-acetyl-6-O-benzyl-3-O-(2-butenyl)-1,2-dideoxy alpha-D-glucopyrano)(2,1-d)-2-oxazoline; D005944:Glucosamine; D000117:Acetylglucosamine