title: Oligosaccharides related to xyloglucan: synthesis and X-ray crystal structure of methyl 2-0-(alpha-L-fucopyranosyl)-beta-D-galactopyranoside.
abstract: The disaccharides methyl 2-O-(alpha-L-fucopyranosyl)-beta-D-galactopyranoside and methyl 2-O-(alpha-L-fucopyranosyl)-alpha-D-galactopyranoside have been synthesised using the assisted halide reaction of tri-O-benzyl-alpha-L-fucopyranosyl bromide with methyl 3,4,6-tri-O-benzyl-beta-D-galactopyranoside and methyl 3,4,6-tri-O-benzyl-alpha-D-galactopyranoside to construct the interresidue glycosidic linkages. A crystal structure of methyl 2-O-(alpha-L-fucopyranosyl)-beta-D-galactopyranoside was determined using Mo-K alpha X-ray data at 183 K. The space group is P1 (No. 1) with the unit cell containing two molecules of the disaccharide with unique conformations and a water molecule. The structure was refined to R = 0.0566 for 2969 reflections. The L-fucopyranosyl and D-galactopyranosyl residues have the nominal 1C4 and 4C1 conformations, respectively. The interresidue torsion angles are comparable with those generated in a recent molecular modelling 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: D002236:Carbohydrate Conformation; D002240:Carbohydrate Sequence; D018360:Crystallography, X-Ray; D004187:Disaccharides / Q000138:chemical synthesis* / Q000737:chemistry*; D005936:Glucans; D006860:Hydrogen Bonding; D009682:Magnetic Resonance Spectroscopy; D008958:Models, Molecular; D008968:Molecular Conformation; D008969:Molecular Sequence Data; D015394:Molecular Structure; D011134:Polysaccharides / Q000737:chemistry*; D014990:Xylans
chemical_list: D004187:Disaccharides; D005936:Glucans; D011134:Polysaccharides; D014990:Xylans; C103521:methyl 2-O-fucopyranosyl-galactopyranoside; C029353:xyloglucan