title: Regioselective glycosylation of 7-azapteridines and conversion of the 7-azapteridine nucleosides into 6-azapurine nucleosides.
abstract: The regioselective glycosylation of reumycins (3) reacted with 1-O-acetyl-2,3,5-tri-O-benzoyl-beta-D-ribofuranose (4) and BSTFA in acetonitrile at 90 degrees C followed by reaction of SnCl(4) in dioxane at room temperature afforded the 1-(2',3',5'-tri-O-benzoyl-beta-D-ribofuranosyl)- 6-methylpyrimido[5,4-e][1,2,4]triazine-5,7(1H,6H)-diones (5) (toxoflavin type nucleosides), while the similar alkylations with 1-bromo-2,3,5-tri-O-benzoyl-beta-D-ribofuranose (6) and KHCO(3) in DMF at 100 degrees C gave predominantly the 8-(2',3',5'-tri-O-benzoyl-beta-D-ribofuranosyl)-6-methylpyrimido[5,4-e]-[1,2,4]triazine-5,7(6H,8H)-diones (7) (fervenulin type nucleosides). On the other hand, treatment of the 7-azapteridine nucleosides (5 and 7) in alkali solution at room temperature yielded the corresponding 1-(beta-D-ribofuranosyl)-5-methyl-1H-imidazo[4,5-e][1,2,4]- triazin-6(5H)-ones (8) and 7-(beta-D-ribofuranosyl)-5-methyl-5H-imidazo[4,5-e][1,2,4]triazin-6(7H)-ones (9) [6-azapurine nucleosides] by benzilic acid rearrangement. Some 7-azapteridine nucleosides (5 and 7-9) showed antitumor activities and anti-coccidiosis activities.
authors.affiliation: Division of Pharmaceutical Sciences, Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University, 1-1-1, Tsushima-naka, Okayama 700-8530, Japan. nagamatsu@pheasant.pharm.okayama-u.ac.jp
authors.forename: Tomohisa
authors.initials: T
authors.lastname: Nagamatsu
authors.forename: Jun
authors.initials: J
authors.lastname: Ma
authors.forename: Shinya
authors.initials: S
authors.lastname: Akiba
mesh_terms: D006031:Glycosylation; D011621:Pteridines / Q000138:chemical synthesis* / Q000737:chemistry; D011684:Purine Nucleosides / Q000138:chemical synthesis* / Q000737:chemistry; D011744:Pyrimidinones / Q000138:chemical synthesis / Q000737:chemistry; D014227:Triazines / Q000138:chemical synthesis / Q000737:chemistry
chemical_list: D011621:Pteridines; D011684:Purine Nucleosides; D011744:Pyrimidinones; D014227:Triazines