Synthesis of mannose-containing analogues of (1-->6)-branched (1-->3)-glucohexaose.
Coupling of the trisaccharide acceptor 2,4,6-tri-O-acetyl-beta-D-glucopyranosyl-(1-->3)-[2,3,4,6-tetra-O-benzoyl-beta-D-glucopyranosyl-(1-->6)]-5-O-acetyl-1,2-O-isopropylidene-alpha-D-glucofuranose (2) with the trisaccharide donor 2,3,4,6-tetra-O-benzoyl-alpha-D-annopyranosyl-(1-->3)-[2,3,4,6-tetra-O-benzoyl-beta-D-glucopyranosyl-(1-->6)]-2,4-di-O-acetyl-alpha-D-glucopyranosyl trichloroacetimidate (1) gave an alpha-linked hexasaccharide 3, while coupling of 2 with the trisaccharide donor 2,3,4,6-tetra-O-benzoyl-alpha-D-mannopyranosyl-(1-->3)-[2,3,4,6-tetra-O-benzoyl-alpha-D-mannopyranosyl-(1-->6)]-2,4-di-O-acetyl-alpha-D-glucopyranosyl trichloroacetimidate (7) produced alpha- 8 and beta-linked 12 hexasaccharides in a ratio of 3:2. Deprotection of 3, 8, and 12 afforded the analogues of the immunomodulator beta-D-Glcp-(1-->3)-[beta-D-Glcp-(1-->6)]-alpha-D-Glcp-(1-->3)-beta-D-Glcp-(1-->3)-[beta-D-Glcp-(1-->6)]-D-Glcp (A).
Wu
Zicheng
Z
Research Center for Eco-Environmental Sciences, Academia Sinica, P.O. Box 2871, 100085, Beijing, China.
Kong
Fanzuo
F
D002236:Carbohydrate Conformation; D002240:Carbohydrate Sequence; D005947:Glucose / Q000737:chemistry*; D008358:Mannose / Q000737:chemistry*; D008969:Molecular Sequence Data; D015394:Molecular Structure; D009844:Oligosaccharides / Q000138:chemical synthesis* / Q000737:chemistry*
D009844:Oligosaccharides; D005947:Glucose; D008358:Mannose