Synthetic study on a novel Asn-linked core structure: synthesis of a pentasaccharide α-d-Man-(1→3)-[α-d-Man-(1→6)]-β-d-Man-(1→4)-[β-d-GlcNAc-(1→6)]-β-d-GlcNAc→OMp

Synthesis of a pentasaccharide α-d-Man-(1→3)-[α-d-Man-(1→6)]-β-d-Man-(1→4)-[β-d-GlcNAc(1→6)]-β-d-GlcNAc→OMp (2) is described. A comparison between the 1H NMR data of 2 and those of a novel Asn-linked core structure 1 containing a new GlcNAc residue suggests an α-d-configuration for the new linkage.