The Synthesis of an O,C-Trisaccharide: The O,C-Analog of Methyl 4′-O-β-d-glucopyranosylgentiobioside

The synthesis of an O,C-trisaccharide, namely methyl O-β-d-glucopyranosyl-(1→4)-C-β-d-glucopyranosyl-(1→6)-α-d-glucopyranoside, was achieved in 14 steps by way of the nitro–aldol coupling of hepta-O-acetyl-β-cellobiosylnitromethane and methyl 6-aldehydo-2,3,4-tri-O-benzyl-α-d-gluco-hexodialdo-1,5-pyranoside, followed by the elaboration of the coupling product. The resulting O,C-trisaccharide constitutes a potential inhibitor of the β-glucanases of the cellulase family. The perbenzylated derivative of cellobiosylnitromethane was also prepared. Both disaccharide-C-glycosides constitute useful starting materials for the preparation of higher mixed O,C-oligosaccharides.