Ultrasound-assisted one-pot, four component synthesis of 4-aryl 3,4-dihydropyridone derivatives.

The condensation of Meldrum's acid, aromatic aldehydes, alkyl acetoacetates and ammonium acetate in glacial acetic acid under ultrasound irradiation at room temperature results in the formation of 3,4-dihydropyridone derivatives (4a-p) in 85-96% yields. Compared with conventional methods, the main advantages of the present procedure are milder conditions, shorter reaction times and higher yields.

1H and 13C spectral assignment of 4-aryl-1,4,5,6,7,8-hexahydro-2,7,7,5-oxo-quinolines 3-substituted derivatives.

The 1H and 13C NMR spectroscopic data for 4-aryl-1,4,5,6,7,8-hexahydro-2,7,7,5-oxo-quinoline 3-substituted derivatives have been fully assigned by the combination of one- and two dimensional experiments (DEPT, HMBC, HMQC, COSY, NOE).