Nucleosides. II. Synthesis and Properties of 3,4-Diaryl-4,5-dihydro-1-(β-D-ribofuranosyl)-1,2,4-triazole-5-thiones

Abstract

3,4-Diaryl-4,5-dihydro-1,2,4-triazole-5-thiones (1a-c) were silylated to give compounds (2a-c) which were condensed with 1-O-acetyl-2,3,5-tri-O-benzoyl-β-D-ribofuranose (3) in the presence of trimethylsilyl trifluoromethane sulfonate to afford the corresponding nucleosides 4a-c. Treatment of 4a-c with sodium methoxide in methanol at room temperature afforded the debenzoylated nucleosides 5a-c. The reaction of 5a with acetone in the presence of p-toluenesulfonic acid gave the 2′, 3′-isopropylidene derivative (6a). Phosphorylation of 6a with phosphoryl chloride and triethylphosphate followed by treatment with barium hydroxide afforded barium 3,4-diphenyl-4,5-dihydro(β-D-ribofuranosyl)-1,2,4-triazole-5-thione-5′- monophosphate, which gave after lyophilization the free acid (7a)