title: Acid-catalyzed dehydrative cyclization of 4-(D-galacto -pentitol-1-yl)-2-phenyl-2H-1,2,3-triazole. synthesis and anomeric configuration of D-lyxo-C-nucleoside analogs.
abstract: Dehydration of 4-(D-galacto-pentitol-1-yl)-2-phenyl-2H-1,2,3-triazole with 20% methanolic sulfuric acid afforded the anomeric pairs of nucleosides, 4-(alpha-D-lyxopyranosyl)-2-phenyl-2H-1,2,3-triazole (major component) and its beta-anomer, as well as 4-(alpha-D-lyxofuranosyl)-2H-1,2,3-triazole and its beta-anomer. The four anomeric C-nucleosides were separated by chromatography, and their structure and anomeric configuration were determined by periodate oxidation, acylation, and NMR spectroscopy as well as mass spectrometry. The anomeric assignment from optical rotation was not in agreement with final structure assignment and represented a violation of the Hudson isorotation rules. NOE studies and X-ray diffraction measurements confirmed the anomeric configuration.
authors.affiliation: Department of Chemistry, Faculty of Science, Alexandria University, Egypt.
authors.forename: M A
authors.initials: MA
authors.lastname: Sallam
authors.forename: S M
authors.initials: SM
authors.lastname: Abdel Megid
authors.forename: L B
authors.initials: LB
authors.lastname: Townsend
mesh_terms: D002384:Catalysis; D008968:Molecular Conformation; D015394:Molecular Structure; D019906:Nuclear Magnetic Resonance, Biomolecular; D009705:Nucleosides / Q000138:chemical synthesis* / Q000737:chemistry; D009904:Optical Rotation; D013237:Stereoisomerism; D013402:Sugar Alcohols / Q000737:chemistry; D013463:Sulfuric Acid Esters; D014230:Triazoles / Q000737:chemistry; D014961:X-Ray Diffraction
chemical_list: C429011:4-(galacto-pentitol-1-yl)-2-phenyl-2H-1,2,3-triazole; D009705:Nucleosides; D013402:Sugar Alcohols; D013463:Sulfuric Acid Esters; D014230:Triazoles; C033522:methyl sulfate