Direct SNAr amination of fluorinated imidazo[4,5-c]pyridine nucleosides: efficient syntheses of 3-fluoro-3-deazaadenosine analogs

3,6-Difluoro-3-deazapurine ribonucleoside analogs underwent direct SNAr amination reactions with liquid ammonia to give 3-fluoro-3-deazaadenosine analogs in excellent yield; in contrast, 6-chloro-3-fluoro-3-deazapurine nucleosides were inert.