title: Synthesis of disaccharide fragments of dermatan sulfate.
abstract: Condensation of crystalline methyl 2-azido-4,6-O-benzylidene-2-deoxy-beta-D-galactopyranoside with methyl (2,3,4-tri-O-acetyl-alpha-L-idopyranosyl bromide)uronate in dichloromethane, in the presence of silver triflate and molecular sieve, provided 54% of methyl 2-azido-4,6-O-benzylidene-2-deoxy-3-O-(methyl 2,3,4-tri-O-acetyl-alpha-L-idopyranosyluronate)-beta-D-galactopyranoside . The use of methyl (2,3,4-tri-O-acetyl-alpha-L-idopyranosyl trichloroacetimidate)uronate as glycosyl donor, in the presence of trimethylsilyl triflate, improved the yield to 68%. Regioselective opening of the benzylidene group with sodium cyanoborohydride followed successively by O-sulfation with the sulfur trioxide-trimethylamine complex, saponification, catalytic hydrogenolysis and selective N-acetylation gave the disodium salt of methyl 2-acetamido-2-deoxy-3-O-(alpha-L-idopyranosyluronic acid)-4-O-sulfo-beta-D-galactopyranoside. Condensation of methyl 2-azido-4,6-O-benzylidene-2-deoxy-beta-D-galactopyranoside with methyl (2,3,4-tri-O-acetyl-alpha-D-glucopyranosyl bromide)uronate in dichloromethane, in the presence of silver triflate and molecular sieve, gave methyl 2-azido-4,6-O-benzylidene-2-deoxy-3-O-(methyl 2,3,4-tri-O-acetyl-beta-D-glucopyranosyluronate)-beta-D-galactopryano  side in 85% yield. The sequence already described then gave the disodium salt of methyl 2-acetamido-2-deoxy-3-O-(beta-D-glucopyranosyluronic acid)-4-O-sulfo-beta-D-galactopyranoside.
authors.affiliation: Ecole Normal Supérieure, Laboratoire de Chimie, Paris, France.
authors.forename: A
authors.initials: A
authors.lastname: Marra
authors.forename: X
authors.initials: X
authors.lastname: Dong
authors.forename: M
authors.initials: M
authors.lastname: Petitou
authors.forename: P
authors.initials: P
authors.lastname: Sinay
mesh_terms: D002240:Carbohydrate Sequence; D002807:Chondroitin / Q000031:analogs & derivatives*; D003871:Dermatan Sulfate / Q000031:analogs & derivatives* / Q000138:chemical synthesis; D004187:Disaccharides / Q000138:chemical synthesis*; D008969:Molecular Sequence Data
chemical_list: D004187:Disaccharides; C063859:methyl 2-acetamido-2-deoxy-3-O-(alpha-idopyranosyluronic acid)-4-O-sulfo-beta-galactopyranoside; C063860:methyl 2-acetamido-2-deoxy-3-O-(beta-glucopyranosyluronic acid)-4-O-sulfo-beta-galactopyranoside; D003871:Dermatan Sulfate; D002807:Chondroitin