title: Synthesis of the alpha-D-GlcpA-(1-->3)-alpha-L-Rhap-(1-->2)-L-Rha trisaccharide isolated from the cell wall hydrolyzate of the green alga, Chlorella vulgaris.
abstract: The title trisaccharide was synthesized from 6-O-acetyl-2,3,4-tri-O-benzyl-alpha-D-glucopyranosyl chloride (10), ethyl 2,4-di-O-benzyl-1-thio- (5) and benzyl 3,4-di-O-benzyl-alpha-L-rhamnopyranoside (9). The disaccharide 11 obtained from compounds 5 and 10 was used as the glycosyl donor to glycosylate the rhamnopyranoside derivative 9 having free OH-2 using the NIS-AgOTf-mediated glycosylation methodology. Zemplén deacetylation of the trisaccharide 12 resulted in the 6"-OH derivative (13), which was selectively oxidized with CrO3 to the uronic acid derivative 14. The benzyl groups were removed by catalytic hydrogenolysis to furnish the target trisaccharide (1).
authors.affiliation: Research Group for Carbohydrates of the Hungarian Academy of Sciences, PO Box 55, H-4010, Debrecen, Hungary.
authors.forename: F
authors.initials: F
authors.lastname: Sajtos
authors.forename: J
authors.initials: J
authors.lastname: Hajkó
authors.forename: K E
authors.initials: KE
authors.lastname: Kövér
authors.forename: A
authors.initials: A
authors.lastname: Lipták
mesh_terms: D002240:Carbohydrate Sequence; D002458:Cell Fractionation; D002473:Cell Wall / Q000737:chemistry*; D002708:Chlorella / Q000737:chemistry*; D004187:Disaccharides / Q000302:isolation & purification / Q000378:metabolism; D006868:Hydrolysis; D008969:Molecular Sequence Data; D014312:Trisaccharides / Q000138:chemical synthesis* / Q000302:isolation & purification
chemical_list: D004187:Disaccharides; D014312:Trisaccharides; C438443:glucopyranuronosyl-(1-3)-rhamnopyranosyl-(1-2)-rhamnopyranose