A novel synthesis of pyrimido[4,5-b]quinoline-2(3H),4(10H)-diones (5-deazaflavins) and analogues by the oxidative cyclization of 5,5′-arylmethylenebis-(6-alkylamino-3-methyluracils)

Abstract

The oxidative coupling of 5,5′-arylmethylenebis-(6-alkylamino-3-methyluracils), prepared by the condensation of 6-alkylamino-3-methyluracils and arenecarbaldehydes, with diethyl azodiformate afforded the corresponding pyrimido[4,5-b]quinoline-2(3H),4(10H)-diones (5-deazaflavins). This synthetic method was successfully applied to the preparation of 5-deazaflavin-type compounds such as a benzologue, a thiophen analogue, or a nitrogen analogue of 5-deazaflavin. The 8-chloro-5-deazaflavin was converted into the corresponding 8-amino-derivatives by treatment with amines.