Synthesis of some oligosaccharides containing the O-(2-acetamido-2-deoxy-β-d-glucopyranosyl)-(1→2)-O-α-d-mannopyranosyl unit. Potential substrates for UDP-GlcNAc: α-d-mannopyranosyl-(1→6)-N-acetyl-β-d-glucosaminyl-transferase (GnT-V)

Four different oligosaccharides containing the 2-acetamido-2-deoxy-β-d-glucopyranosyl-(1→2)-α-d-mannopyranosyl sequence as a terminal disaccharide unit were synthesized, namely: 4-nitrophenyl O-(2-acetamido-2-deoxy-β-d-glucopyranosyl)-(1→2)-O-α-d-mannopyranosyl-(1→6)-β-d-mannopyranoside (27), 4-nitrophenyl O-(2-acetamido-2-deoxy-β-d-glucopyranosyl)-(1→2)-O-α-d-mannopyranosyl-(1→6)-β-d-glucopyranoside (29), allyl O-(2-acetamido-2-deoxy-β-d-glucopyranosyl-(1→2)-α-d-mannopyranosyl-(1→6)-β-d-glucopyranoside (31), and allyl O-(2-acetamido-2-deoxy-β-d-glucopyranosyl)-(1→2)-O-α-d-mannopyranosyl-(1→6)-O-β-d-glucopyranosyl-(1→4)-β-d- glucopyranoside (33). A common glycosyl donor, namely, 2-O-(2-acetamido-3,4,6-tri-O-acetyl-2-deoxy-β-d-glucopyranosyl)-3,4,6-tri-O-acetyl-α-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.