OLIGOSACCHARIDES RELATED TO XYLOGLUCAN, SYNTHESIS AND X-RAY CRYSTAL STRUCTURE OF METHYL 2-O-(ALPHA-L-FUCOPYRANOSYL)-BETA-D-GALACTOPYRANOSIDE

摘要

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 P-1 (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 C-1(4) and C-4(1) conformations: respectively, The interresidue torsion angles are comparable with those generated in a recent molecular modelling study. (C) 1996 Elsevier Science Ltd. [References: 36]