Microwave-mediated regioselective synthesis of novel pyrimido[1,2-a]pyrimidines under solvent-free conditions

Ethyl 2-amino-4-aryl-1,4-dihydro-6-phenylpyrimidine-5-carboxylates readily react, under microwave irradiation and solvent-free conditions, with 3-formylchromone or diethyl (ethoxymethylene)malonate to yield novel pyrimido[1,2-a]pyrimidines. The structure of the final products, deduced from the spectral data and confirmed by X-ray analysis, allows us to suggest reaction pathways.