Synthesis of 4 '-O-acetyl-maltose and alpha-D-galactopyranosyl-(1 -> 4)-D-glucopyranose for biochemical studies of amylose biosynthesis

The chemical synthesis of the title compounds as maltose analogs, in which the non-reducing end is modified by acetylation of the 4'-OH group or by re versing its configuration, is reported. For synthesis of the 4'-O-acetylate d analog, p-maltose was converted into its per-O-benzylated-4',6'-O-benzyli dene derivative followed by removal of the benzylidene acetal function and selective silylation at C-6'. Acetylation at C-4' of the obtained silylated compound followed by removal of the benzyl ether protecting groups and sub sequent desilylation afforded the desired analog. The other maltose analog was synthesized via the glycosidation reaction between the glycosyl donor, O-(2,3,4,6-tetra-O-benzyl-alpha/beta -D-galactopyranosyl)trichloroacetimida te and the glycosyl acceptor, phenyl 2,3,6-tri-O-benzyl-1-thio-beta -D-gluc opyranoside followed by removal of the phenylthio group and debenzylation t o provide the desired analog. (C) 2001 Elsevier Science Ltd. All rights res erved.