Synthetic mucin fragments. Benzyl O-(2-acetamido-2-deoxy-alpha-D-glucopyranosyl)-(1----3)-O-beta-D- galactopyranosyl-(1----3)-O-[(2-acetamido-2-deoxy-beta-D-glucopyran osy l)- (1----6)]-2-acetamido-2-deoxy-alpha-D-galactopyranoside and benzyl O-(2-acetamido-2-deoxy-beta-D-glucopyranosyl)-(1----3)-O-beta-D- galactopyranosyl-(1----3)-O-[beta-D-galactopyranosyl-(1----6)]-2-ac eta mido- 2-deoxy-alpha-D-galactopyranoside.

Treatment of benzyl 2-acetamido-2-deoxy-alpha-D-galactopyranoside with 4-methoxybenzaldehyde dimethyl acetal in N,N-dimethylformamide in the presence of 4-toluenesulfonic acid afforded the 4,6-O-(4-methoxybenzylidene) acetal, which was glycosylated with 2,3,4,6-tetra-O-acetyl-alpha-D-galactopyranosyl bromide (1). Reductive ring-opening of the acetal group provided a 6-O-(4-methoxybenzyl) derivative (4) which was glycosylated with 1, followed by removal of the 4-methoxybenzyl ether group, to give benzyl 2-acetamido-2-deoxy-3,4-di-O-(2,3,4,6-tetra-O-acetyl-beta-D-galactopyran osyl)- alpha-D-galactopyranoside (7). The disaccharide diol 5, obtained from 4, and benzyl O-(2-acetamido-3,4,6-tri-O-acetyl-2-deoxy-beta-D-glucopyranosyl-(1----3) -O- (2,4,6-tri-O-acetyl-beta-D-galactopyranosyl)-(1----3)-2-acetamido-2-deox y- alpha-D-galactopyranoside (11) were similarly glycosylated with 1 to afford a trisaccharide derivative 9 and a tetrasaccharide derivative 14, respectively. Diol 11 was also condensed with 2-methyl-(3,4,6-tri-O-acetyl-1,2-di-deoxy-alpha-D-glucopyrano)-[2, 1-d]-2- oxazoline to give a tetrasaccharide derivative 16. O-Deacetylation of trisaccharides 7 and 9, and tetrasaccharides 14 and 16 furnished trisaccharides 8 and 10, and the title tetrasaccharides 15 and 17, respectively. The structures of compounds 8, 10, 15, and 17 were established by 13C-n.m.r. spectroscopy.