无溶剂超声辐射下硝酸镱高效催化合成 1,4-二氢吡啶衍生物

在Yb(NO₃)₃催化下, 芳香醛、 5,5-二甲基-1,3-环己二酮、 乙酰乙酸乙酯和醋酸铵在室温无溶剂条件下经超声辐射一锅法合成了一系列1,4-二氢吡啶衍生物, 反应时间为15~35 min, 产率为86%~97%. 该方法具有条件温和、 反应时间短且产率高的优点. 催化剂Yb(NO₃)₃对环境友好且可循环使用, 为此类化合物的合成提供了一种有效的新方法.

Solvent-free Synthesis of 1,4-Dihydropyridine Derivatives under Ultrasonic Irradiation with Ytterbium Nitrate as Catalyst

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(NO 3) 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(NO 3) 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(NO 3) 3 was environmentally friendly and reused for three times without any noticeable decrease in the catalytic activity.