title: Synthesis of the isomeric trisaccharides, methyl O-alpha-L-fucopyranosyl- (1----3, 4, and 6)-O-(2-acetamido-2-deoxy-beta-D-glucopyranosyl)-(1----3)-beta- D-galactopyranoside.
abstract: Benzylation of methyl 3-O-(2-acetamido-4,6-O-benzylidene-2-deoxy-beta-D- glucopyranosyl)-2,4,6-tri-O-benzyl-beta-D-galactopyranoside with benzyl bromide in N,N-dimethylformamide in the presence of sodium hydride afforded methyl 3-O- (2-acetamido-3-O-benzyl-4,6-O-benzylidene-2-deoxy-beta-D-glucopyranosyl) -2,4,6- tri-O-benzyl-beta-D-galactopyranoside (3). Reductive ring-opening of the benzylidene group of 3 gave methyl 3-O-(2-acetamido-3,6-di-O-benzyl-2-deoxy-beta-D- glucopyranosyl)- 2,4,6-tri-O-benzyl-beta-D-galactopyranoside (4). Cleavage of the 4,6-acetal group of 3 with hot, 80% aqueous acetic acid afforded the diol (5). Compounds 3, 4, and 5 were each subjected to halide ion-catalyzed glycosylation with 2,3,4-tri-O-benzyl-alpha-L-fucopyranosyl bromide to produce the corresponding trisaccharide derivatives, which, on catalytic hydrogenation, furnished the title trisaccharides, respectively.
authors.affiliation: Department of Gynecologic Oncology, Roswell Park Memorial Institute, New York State Department of Health, Buffalo 14263.
authors.forename: R K
authors.initials: RK
authors.lastname: Jain
authors.forename: K
authors.initials: K
authors.lastname: Kohata
authors.forename: S A
authors.initials: SA
authors.lastname: Abbas
authors.forename: K L
authors.initials: KL
authors.lastname: Matta
mesh_terms: D009844:Oligosaccharides / Q000138:chemical synthesis*; D014312:Trisaccharides / Q000138:chemical synthesis*
chemical_list: D009844:Oligosaccharides; D014312:Trisaccharides