Base-catalyzed one-step synthesis of 5,7-disubstituted-1,2,4-triazolo[1,5-a]pyrimidines

We report a practical high-yield synthesis of 5,7-disubstituted-1,2,4-triazolo[1,5-a]pyrimidines using a base-assisted cyclocondensation of chalcone and 1,2,4-triazol-3-amine in an open reaction vessel. The same conditions can also be used for the preparation of novel imidazo[1,2-a]pyrimidine derivatives.