Solvent-free synthesis of 4-aryl substituted 5-alkoxycarbonyl-6-methyl-3,4-dihydropyridones under microwave irradiation

4-Aryl substituted 5-alkoxycarbonyl-6-methyl-3,4-dihydropyridones have been prepared in one-pot condensation from Meldrumʹs acid, methyl acetoacetate and the appropriate benzaldehyde in the presence of ammonium acetate using microwave irradiation without solvent. This rapid method produced pure products in high yields (81–91%) due essentially to a specific non-thermal microwave effect (17–28%) by conventional heating under the same conditions.