Magnetic nanoparticle supported amine: An efficient and environmental benign catalyst for versatile Knoevenagel condensation under ultrasound irradiation
作者:Anguo Ying、Limin Wang、Fangli Qiu、Huanan Hu、Jianguo Yang
DOI:10.1016/j.crci.2014.05.012
日期:2015.2
Résumé Amine functionalized silica coated Fe3O4 nanoparticles (SiO2@MNP-A) were successfully prepared as a novel heterogeneous amine. The catalyst was characterized by XRD, FT-IR, TEM, magnetic measurement, elemental analysis and was found to be a magnetically separable and highly active catalyst for ambient Knoevenagel condensation of aromatic aldehydes and α-aromatic (heteroaromatic or polyaromatic)-substituted methylene compounds in water under ultrasonic irradiation to afford the corresponding products in good to excellent yields. Very interestingly, SiO2@MNP-A successfully catalyze the reaction of the non-cyano substituted compound with benzaldehyde to achieve a key intermediate for the preparation of Atorvastatin calcium in green and atom-economic manner. In addition, the catalyst SiO2@MNP-A can be reused for 8 times without any obvious loss of its activity. The role of ultrasonication in the Knoevenagel condensation was also discussed with the assistance of UV–vis spectrometry.
摘要
成功制备了氨基功能化的二氧化硅包覆的Fe3O4纳米颗粒(SiO2@MNP-A),作为一种新型的异相胺催化剂。通过XRD、FT-IR、TEM、磁性测量和元素分析对催化剂进行了表征,结果表明其为一种可磁性分离的高活性催化剂,用于在超声辐射下在水中进行芳香醛和α-芳香(含异构体或多芳香)取代亚甲基化合物的室温Knoevenagel缩合反应,能在良好到优异的产率下获得相应产物。非常有趣的是,SiO2@MNP-A成功催化了非氰取代化合物与苯甲醛的反应,从而实现了以绿色和原子经济的方式制备阿托伐他汀钙的关键中间体。此外,催化剂SiO2@MNP-A可重复使用8次,而其活性几乎没有明显损失。还通过紫外-可见光谱法讨论了超声对Knoevenagel缩合反应的影响。