Synthesis of some oligosaccharides containing the O-(2-acetamido-2-deoxy- beta-D-glucopyranosyl)-(1----2)-O-alpha-D-mannopyranosyl unit. Potential substrates for UDP-GlcNAc:alpha-D-mannopyranosyl-(1----6)-N-acetyl-beta-D- glucosaminyltransferase (GnT-V).

Four different oligosaccharides containing the 2-acetamido-2-deoxy-beta-D-glucopyranosyl-(1----2)-alpha-D-mannopyran osy l sequence as a terminal disaccharide unit were synthesized, namely: 4-nitrophenyl O-(2-acetamido-2-deoxy-beta-D- glucopyranosyl)-(1----2)-O-alpha-D-mannopyranosyl-(1----6)-beta-D- mannopyranoside (27), 4-nitrophenyl O-(2-acetamido-2-deoxy-beta-D-glucopyranosyl)-(1----2)-O-alpha-D-mann opy ranosyl - (1----6)-beta-D-glucopyranoside (29), allyl O-(2-acetamido-2-deoxy-beta-D-glucopyranosyl-(1----2)-alpha-D- mannopyranosyl-(1----6)-beta-D-glucopyranoside (31), and allyl O-(2-acetamido-2-deoxy-beta-D-glucopyranosyl)-(1----2)-O-alpha-D- mannopyranosyl-(1----6)-O-beta-D-glucopyranosyl-(1----4)-beta-D-gluco pyr anoside (33). A common glycosyl donor, namely, 2-O-(2-acetamido-3,4,6-tri-O-acetyl-2-deoxy-beta-D- glucopyranosyl)-3,4,6-tri-O-acetyl-alpha-D-mannopyranosyl bromide was employed for the synthesis of 27, 29, 31, and 33, the structures of which were all established by 13C-n.m.r. spectroscopy.