title: Oligosaccharides related to xyloglucan: synthesis and X-ray crystal structure of methyl alpha-L-fucopyranosyl-(1-->2)-beta-D-galactopyranosyl-(1-->2)-alpha-D-x ylopyranoside and the synthesis of methyl alpha-L-fucopyranosyl-(1-->2)-beta-D-galactopyranosyl-(1-->2)-beta-D-xy lopyranoside.
abstract: Trisaccharides, methyl alpha-L-fucopyranosyl-(1-->2)-beta-D-galactopyranosyl-(1-->2)-alpha-D-xy lopyranoside and methyl alpha-L-fucopyranosyl-(1-->2)-beta-D-galactopyranosyl-(1-->2)-beta-D-xyl opyranoside, which are related to the side chain of xyloglucan have been synthesised. The beta-galactopyranosyl linkage of each was constructed using silver trifluoromethanesulfonate-promoted glycosylations of 2-O-acetyl-3,4,6-tri-O-benzyl-beta-D-galactopyranosyl chloride and the corresponding anomer of methyl 3,4-tri-O-benzyl-D-xylopyranoside. The resulting disaccharides were deacetylated and fucosylated using assisted halide reactions with tri-O-benzyl-alpha-L-fucopyranosyl bromide. Hydrogenolytic debenzylation of the resulting protected trisaccharides gave the methyl glycosides of the fucose-containing xyloglucan side chain. The structure of methyl alpha-L-fucopyranosyl-(1-->2)-beta-D-galactopyranosyl-(1-->2)-alpha-D-xy lopyranoside as the monohydrate was confirmed by an X-ray crystallographic study.
authors.affiliation: Department of Chemistry, University of Otago, Dunedin, New Zealand.
authors.forename: D K
authors.initials: DK
authors.lastname: Watt
authors.forename: D J
authors.initials: DJ
authors.lastname: Brasch
authors.forename: D S
authors.initials: DS
authors.lastname: Larsen
authors.forename: L D
authors.initials: LD
authors.lastname: Melton
authors.forename: J
authors.initials: J
authors.lastname: Simpson
mesh_terms: D002240:Carbohydrate Sequence; D018360:Crystallography, X-Ray; D005936:Glucans; D006860:Hydrogen Bonding; D009682:Magnetic Resonance Spectroscopy; D008958:Models, Molecular; D008969:Molecular Sequence Data; D009844:Oligosaccharides / Q000737:chemistry*; D011134:Polysaccharides / Q000138:chemical synthesis*; D013237:Stereoisomerism; D014312:Trisaccharides / Q000138:chemical synthesis*; D014990:Xylans
chemical_list: D005936:Glucans; D009844:Oligosaccharides; D011134:Polysaccharides; D014312:Trisaccharides; D014990:Xylans; C415345:methyl fucopyranosyl-1-2--galactopyranosyl-1-2-xylopyranoside; C029353:xyloglucan