title: Synthetic mucin fragments: benzyl 2-acetamido-6-O-(2-acetamido-2-deoxy-beta- D-glucopyranosyl)-2-deoxy-3-O-beta-D-galactopyranosyl-alpha-D- galactopyranoside and benzyl 2-acetamido-6-O-(2-acetamido-2-deoxy-beta-D-glucopyranosyl)- 3-O-[6-O-(2-acetamido-2-deoxy-beta-D-glucopyranosyl)-beta-D- galactopyranosyl]-2-deoxy-alpha-D-galactopyranoside.
abstract: Glycosylation of benzyl 2-acetamido-4,6-O-benzylidene-2-deoxy-alpha-D- galactopyranoside with 2,3,4,6-tetra-O-acetyl-alpha-D-galactopyranosyl bromide, catalyzed by mercuric cyanide, afforded benzyl-2-acetamido-4,6-O-benzylidene-2-deoxy-3- O-(2,3,4,6-tetra-O-acetyl-beta-D-galactopyranosyl)-alpha-D- galactopyranoside (3). O-Deacetylation of 3 gave benzyl 2-acetamido-4,6-O-benzylidene-2-deoxy-3-O-beta- D-galactopyranosyl-alpha-D-galactopyranoside which, on acetalation with benzaldehyde-zinc chloride complex followed by acetylation of the resulting dibenzylidene acetal, gave the disaccharide diacetate (7). Cleavage of the acetal groups of 3 and 7 in hot, 80% aqueous acetic acid furnished, respectively, the disaccharide tetraacetate (4) and diacetate (8). O-Deacetylation of 8 in methanolic sodium methoxide gave the disaccharide (9). Condensation of 4 or 8 with 2-methyl-(3,4,6-tri-O-acetyl-1,2- dideoxy-alpha-D-glucopyrano)-[2,1-d]-2-oxazoline, followed by O-deacetylation, afforded the title tri- and tetra-saccharides, 12 and 14, respectively. The structures of compounds 9, 12, and 14 were established by 13C-n.m.r. spectroscopy.
mesh_terms: D007202:Indicators and Reagents; D009682:Magnetic Resonance Spectroscopy; D009077:Mucins / Q000138:chemical synthesis*; D009844:Oligosaccharides / Q000138:chemical synthesis*; D009904:Optical Rotation
chemical_list: D007202:Indicators and Reagents; D009077:Mucins; D009844:Oligosaccharides