A new and practical method for the synthesis of 6-aryl-5,6-dihydropyrido[2,3-]pyrimidine-4,7(3,8)-diones

A one step general synthetic methodology for the synthesis of 6-aryl-5,6-dihydropyrido[2,3-d]pyrimidine-4,7(3H,8H)-diones (17{} () and 20{} ()) is described. This methodology is based on reacting a 2-aryl-substituted acrylate (16{}) with the corresponding 6-aminopyrimidin-4(3-one (13 (; 19 ()) in presence of a base under microwave irradiation. The resulting pyrido[2,3-]pyrimidines present an aryl substituent at position C6, precisely the one directly related to the biological activity of such heterocycles. These protocols have been extended to other 2-alkyl-substituted and 3-alkyl (or aryl)-substituted acrylates but with lower yields.