title: A convergent synthesis of core 2 branched sialylated and sulfated oligosaccharides.
abstract: A convergent pathway for the syntheses of core 2 oligosaccharide analogues 1 and 2, and a natural form sialylated and sulfated hexasaccharide 3 was developed. Construction of pentasaccharides 24, 27 and hexasaccharide 28 was achieved by complete regioselective glycosylation of the 6-OH in the acceptors 5, 7 and 8, respectively, owing to the much higher reactivity of the primary hydroxyl group over the secondary axial hydroxyl group in these structures. Stereoselective sialylation was accomplished using donor 10 with defined configuration established through X-ray crystallographic analysis. Target oligosaccharides 1-3 were then obtained by the systematic deprotection of intermediates 24, 27 and 29. With these target oligosaccharides 1-3 obtained, biological evaluations of these molecules as enzyme substrates was undertaken and selectin binding studies are planned.
authors.affiliation: Molecular & Cellular Biophysics, Roswell Park Cancer Institute, Elm & Carlton Streets, Buffalo, NY 14263, USA.
authors.forename: Jie
authors.initials: J
authors.lastname: Xia
authors.forename: James L
authors.initials: JL
authors.lastname: Alderfer
authors.forename: Thamarapu
authors.initials: T
authors.lastname: Srikrishnan
authors.forename: E V
authors.initials: EV
authors.lastname: Chandrasekaran
authors.forename: Khushi L
authors.initials: KL
authors.lastname: Matta
mesh_terms: D002240:Carbohydrate Sequence; D018360:Crystallography, X-Ray; D007202:Indicators and Reagents; D009682:Magnetic Resonance Spectroscopy; D008745:Methylation; D008958:Models, Molecular; D008968:Molecular Conformation; D008969:Molecular Sequence Data; D009844:Oligosaccharides / Q000138:chemical synthesis*; D012794:Sialic Acids / Q000737:chemistry; D021241:Spectrometry, Mass, Electrospray Ionization; D013431:Sulfates / Q000737:chemistry
chemical_list: D007202:Indicators and Reagents; D009844:Oligosaccharides; D012794:Sialic Acids; D013431:Sulfates