Purines. LXIV. Syntheses of 9-Methyl-2-azaadenine 1-Oxide, Its O-Methyl Derivative, and 1-Substituted 5-Azidoimidazole-4-carboxamides

Abstract

Diazotization of 5-amino-N'-methoxy-1-methylimidazole-4-carboxamidine (4a) with NaNO₂ in 1N aqueous HCl was found to give the 1-methoxy-2-azaadenine derivative 8a·HI, which produced 5-azido-1-methylimidazole-4-carbonitrile (5a) on treatment with aqueous Na₂CO₃. The ribosyl analogue 5b, obtained from the riboside 4b by similar diazotization, was utilized for the synthesis of 5-azido-1-β-D-ribofuranosylimidazole-4-carboxamide (9b), a novel AICA riboside analogue. On heating in HCONMe₂ at 70°C for 10min, 8a·HI yielded the 1-N-oxide 7a. Several reactions to transform the functional groups in 5a were also investigated.