Abstract: 1,4-Dihydropyridine(DHP) derivatives are important class of pharmacological active compounds. In order to develop enriched methods for synthesis of 1,4-dihydropyridine derivatives, an one-pot four component Hantzsch condensation reaction of aryl aldehydes, 5,5-dimethyl-1,3-cyclohex-aedione, ethyl acetoacetate and ammonium acetate was investigated by employing Yb(NO₃)₃ as catalyst, without solvent under ultrasonic irradiation at room temperature. It was found that the reaction was carried out in the presence of Yb(NO₃)₃, the yield ranged from 86% to 97%, the reaction time was 15-35 min. Compared to the classical Hantzsch condensation reaction, the main advantages of the present procedure were milder conditions, shorter reaction time and higher yields, which afforded an effective method to synthesize 1,4-dihydropyridine derivatives. Further study showed that Yb(NO₃)₃ was environmentally friendly and reused for three times without any noticeable decrease in the catalytic activity.

Key words: Yb(NO₃)₃, Solvent-free synthesis, Ultrasonic irradiation, 1,4-Dihydropyridine derivative