Synthetic mucin fragments. Methyl 6-O-(2-acetamido-2-deoxy-beta-D- glucopyranosyl)-beta-D-galactopyranoside, methyl 3,4-di-O-(2-acetamido-2-deoxy- beta-D-glucopyranosyl)-beta-D-galactopyranoside, and methyl O-(2-acetamido-2- deoxy-beta-D-glucopyranosyl)-(1----3)-O-beta-D-galactopyranosyl-(1---- 3)-O-(2- acetamido-2-deoxy-beta-D-glucopyranosyl)-(1----3)-beta-D-galactopyr ano side.
Condensation of methyl 2,6-di-O-benzyl-beta-D-galactopyranoside with 2-methyl-(3,4,6-tri-O-acetyl-1,2-dideoxy-alpha-D-glucopyrano)-[2,1 -d]-2- oxazoline (1) in 1,2-dichloroethane, in the presence of p-toluenesulfonic acid, afforded a trisaccharide derivative which, on deacetylation, gave methyl 3,4-di-O-(2-acetamido-2-deoxy-beta-D-glucopyranosyl)-2,6-di-O-benzyl-bet a-D- galactopyranoside (5). Hydrogenolysis of the benzyl groups of 5 furnished the title trisaccharide (6). A similar condensation of methyl 2,3-di-O-benzyl-beta-D-galactopyranoside with 1 produced a partially-protected disaccharide derivative, which, on O-deacetylation followed by hydrogenolysis, gave methyl 6-O-(2-acetamido-2-deoxy-beta-D-glucopyranosyl)-beta-D-galactopyranoside (10). Condensation of methyl 3-O-(2-acetamido-4,6-O-benzylidene-2-deoxy-beta-D- glucopyranosyl)-2,4,6-tri-O-benzyl-beta-D-galactopyranoside with 3-O-(2-acetamido-3,4,6-tri-O-acetyl-2-deoxy-beta-D-glucopyranosyl)-2,4,6 -tri-O-acetyl-alpha-D-galactopyranosyl bromide in 1:1 benzene-nitromethane in the presence of powdered mercuric cyanide gave a fully-protected tetrasaccharide derivative, which was O-deacetylated and then subjected to catalytic hydrogenation to furnish methyl O-(2-acetamido-2-deoxy-beta-D-glucopyranosyl)-(1----3)-O-beta- D-galactopyranosyl-(1----3)-O-(2-acetamido-2-deoxy-beta-D-glucopyranosyl )- (1----3)-beta-D-galactopyranoside (15). The structures of 6, 10, and 15 were established by 13C-n.m.r. spectroscopy.
D002236:Carbohydrate Conformation; D002240:Carbohydrate Sequence; D007202:Indicators and Reagents; D009682:Magnetic Resonance Spectroscopy; D009077:Mucins / Q000138:chemical synthesis*; D009844:Oligosaccharides / Q000138:chemical synthesis*; D009904:Optical Rotation
D007202:Indicators and Reagents; D009077:Mucins; D009844:Oligosaccharides