Efficient synthesis of (5-oxo-6,7-dihydro-4H-[1,2,4]triazolo-[1,5-a]pyrimidin-6-yl)acetanilides based on the recyclization of N-arylitaconimides with 3-amino[1,2,4]triazoles

A convenient method for the synthesis of 2-(2-R-5-oxo-6,7-dihydro-4H-[1,2,4]triazolo-[1,5-a]pyrimidin-6-yl)acetanilides based on the regioselective domino reaction of N-arylitaconimides with substituted 3-aminotriazoles was proposed. Presumably, the reaction pathway includes the conjugated aza-addition of the endo-nucleophilic center of triazole to imide, followed by the recyclization of the intermediate to triazolo[1,5-a]pyrimidine.