J. Jacquinet, P. Sinaÿ
Feb 1, 1987
Citations
0
Influential Citations
36
Citations
Journal
Carbohydrate Research
Abstract
Abstract Methyl 2-azido-2-deoxy-β- d -galactopyranoside was subjected in sequence to isopropylidenation, benzylation, acid hydrolysis, and selective acetylation of HO-4, to give amorphous methyl 4-O-acetyl-2-azido-6-O-benzyl-2-deoxy-β- d -galactopyranoside. Condensation with 2,3,4-tri-O-benzyl-6-O-chloroacetyl-α- l -idopyranosyl chloride (easily prepared in three steps from known 1,6-di-O-acetyl-2,3,4-tri-O-benzyl- l -idopyranose) in 1,2-dichloroethane, in the presence of 2,4,6-trimethylpyridine, silver triflate, and molecular sieves, provided, after O-dechloroacetylation, 58% of amorphous methyl 4-O-acetyl-2-azido-6-O-benzyl-2-deoxy-3-O-(2,3,4-tri-O-benzyl-α- l -idopyranosyl)-β- d -galactopyranoside. Reduction with sodium borohydride, followed successively by N-acetylation, oxidation in the presence of chromium trioxide in acetone-sulfuric acid, O-sulfation of the sodium salt with the sulfur trioxide-trimethylamine complex, and catalytic hydrogenolysis, then gave the disodium salt of methyl 2-acetamido-2-deoxy-3-O-(α- l -idopyranosyluronic acid)-4-O-sulfo-β- d -galactopyranoside. The β-linked disaccharide was also isolated (30%) and converted, through the same sequence, into methyl 2-acetamido-2-deoxy-3-O-(β- l -idopyranosyluronic acid)-4-O-sulfo-β- d -galactopyranoside. The non-sulfated analogue of the title disaccharide was obtained on catalytic hydrogenolysis of methyl 2-acetamido-6-O-benzyl-2-deoxy-3-O-(α- l -idopyranosyluronic acid)-β- d -galactopyranoside. The following compounds were also synthesized: methyl 2-acetamido-2-deoxy-3-O-methyl-4-O-sulfo-β- d -galactopyranoside, methyl 2-acetamido-2-deoxy-3-O-methyl-6-O-sulfo-β- d -galactopyranoside, and methyl 2-acetamido-2-deoxy-3-O-methyl-4,6-di-O-sulfo-β- d -galactopyranoside. The conformation of the l -idopyranosiduronate residue of the synthetic disaccharides is discussed.