title: Synthesis of two oligosaccharides, the GPI anchor glycans from S. cerevesiae and A. fumigatus.
abstract: Two oligosaccharides, alpha-D-Manp-(1-->2)-alpha-D-Manp-(1-->2)-alpha-D-Manp-(1-->6)-alpha-D-Manp-(1-->4)-alpha-D-GlcpNAc (I) and alpha-D-Manp-(1-->3)-alpha-D-Manp-(1-->2)-alpha-D-Manp-(1-->2)-alpha-D-Manp-(1-->6)-alpha-D-Manp-(1-->4)-alpha-D-GlcpNAc (II), the glycosylphosphatidylinositol (GPI) anchor glycans from S. cerevesiae and A. fumigatus were synthesized as their methyl glycosides in a regio- and stereoselective manner. The pentasaccharide I was obtained from 6-O-selective glycosylation of methyl 2,3-di-O-benzoyl-alpha-D-mannopyranosyl-(1-->4)-2-acetamido-3,6-di-O-benzoyl-2-deoxy-alpha-D-glucopyranoside (8) with 2-O-acetyl-3,4,6-tri-O-benzoyl-alpha-D-mannopyranosyl-(1-->2)-3,4,6-tri-O-benzoyl-alpha-D-mannopyranosyl trichloroacetimidate (9), followed by benzoylation, deacetylation, and mannosylation, and then by deprotection. The hexasaccharide (II) was obtained via condensation of allyl 3,4,6-tri-O-benzoyl-alpha-D-mannopyranosyl-(1-->2)-3,4,6-tri-O-benzoyl-alpha-D-mannopyranoside (17) with 2,3,4,6-tetra-O-benzoyl-alpha-D-mannopyranosyl-(1-->3)-2,4,6-tri-O-acetyl-alpha-D-mannopyranosyl trichloroacetimidate (16), followed by deallylation, trichloroacetimidation, and coupling with acceptor (8), and finally by deprotection.
authors.affiliation: Research Center for Eco-Environmental Sciences, Academia Sinica, P.O. Box 2871, Beijing 100085, China.
authors.forename: Zuchao
authors.initials: Z
authors.lastname: Ma
authors.forename: Jianjun
authors.initials: J
authors.lastname: Zhang
authors.forename: Fanzuo
authors.initials: F
authors.lastname: Kong
mesh_terms: D000107:Acetylation; D000498:Allyl Compounds / Q000737:chemistry; D001232:Aspergillus fumigatus / Q000737:chemistry*; D002236:Carbohydrate Conformation; D002240:Carbohydrate Sequence; D006027:Glycosides / Q000737:chemistry; D006031:Glycosylation; D017261:Glycosylphosphatidylinositols / Q000737:chemistry*; D008358:Mannose / Q000737:chemistry; D008969:Molecular Sequence Data; D009844:Oligosaccharides / Q000138:chemical synthesis*; D011134:Polysaccharides / Q000737:chemistry*; D012441:Saccharomyces cerevisiae / Q000737:chemistry*
chemical_list: D000498:Allyl Compounds; D006027:Glycosides; D017261:Glycosylphosphatidylinositols; D009844:Oligosaccharides; D011134:Polysaccharides; D008358:Mannose