Regioselective glycosylation of 7-azapteridines and conversion of the 7-azapteridine nucleosides into 6-azapurine nucleosides

• Published in: Nucleic Acids Symposium Series Vol. 52; no. 1; pp. 561 - 562
• Main Authors: Nagamatsu, Tomohisa, Ma, Jun, Akiba, Shinya
• Format: Journal Article
• Language: English
• Published: England Oxford University Press 2008
• Subjects: Glycosylation; Pteridines - chemical synthesis; Pteridines - chemistry; Purine Nucleosides - chemical synthesis; Purine Nucleosides - chemistry; Pyrimidinones - chemical synthesis; Pyrimidinones - chemistry; Triazines - chemical synthesis; Triazines - chemistry
• ISSN: 0261-3166; 1746-8272
• DOI: 10.1093/nass/nrn284

Abstract The regioselective glycosylation of reumycins (3) reacted with 1-O-acetyl-2,3,5-tri-O-benzoyl-β-D-ribofuranose (4) and BSTFA in acetonitrile at 90 °C followed by reaction of SnCl4 in dioxane at room temperature afforded the 1-(2′,3′,5′-tri-O-benzoyl-β-Dribofuranosyl)- 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-Obenzoyl- β-D-ribofuranose (6) and KHCO3 in DMF at 100 °C gave predominantly the 8-(2′,3′,5′-tri-Obenzoyl- β-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-(β-Dribofuranosyl)- 5-methyl-1H-imidazo[4,5-e][1,2,4]- triazin-6(5H)-ones (8) and 7-(β-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.