Methyl 4-O-(4-alpha-D-glucopyranosyloxy-4-methoxybutyl)-alpha-D-+ ++glucopyranosi de, a modified oligosaccharide for studying interactions of carbohydrates with multisite proteins

Methyl 4-O-(4-alpha-D-glucopyranosyloxy-4-methoxybutyl)-alpha-D-glu copyranoside (9) was synthesised by transacetalation from methyl 2,3,6-tri-O-acetyl-4-O-(4,4-dimethoxybutyl)-alpha-D-glucopyranosid e and trimethylsilyl 2,3,4,6-tetra-O-acetyl-alpha-D-glucopyranoside followed by removal of the blocking groups. Compound 9, which is methyl alpha-maltotrioside modified by replacing the middle D-glucosyl residue with an acyclic spacer, competitively inhibits the hydrolysis of p-nitrophenyl alpha-maltotrioside by porcine alpha-amylase.