Hantzsch synthesis of 1,4-dihydropyridine derivatives is accomplished using novel and efficient ZnO/ZrO2 catalyst. The catalysts prepared by facile precipitation and wet impregnation method have been characterized by using techniques like XRD, SEM, EDS, UV-diffuse reflectance spectra, FTIR, XPS, BET surface area. Ex situ Pyridine absorption FTIR spectroscopy is used to determine the Bronsted and Lewis acidic sites. Enhanced activity of the zirconia supported zinc catalyst is attributed to tetragonal phase, more acidic sites and high surface area of the catalyst. The products attained in good to excellent yields in short duration under solvent free condition, minimizing the disposal problem and energy dissipation. The catalyst can be reused umpteen times without significant loss in activity.

中文翻译：

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在无溶剂条件下在 ZnO/ZrO2 催化剂上 Hantzsch 合成 1,4-二氢吡啶衍生物

Hantzsch 合成 1,4-二氢吡啶衍生物是使用新型高效的 ZnO/ZrO2 催化剂完成的。采用简易沉淀法和湿浸渍法制备的催化剂已通过XRD、SEM、EDS、紫外漫反射光谱、FTIR、XPS、BET表面积等技术进行表征。异位吡啶吸收 FTIR 光谱用于确定布朗斯台德和路易斯酸性位点。氧化锆负载的锌催化剂的活性增强归因于催化剂的四方相、更多酸性位点和高表面积。在无溶剂条件下，产品在短时间内获得了良好到极好的收率，最大限度地减少了处理问题和能量耗散。催化剂可以重复使用无数次而不会显着降低活性。