New magnetic nanocomposites of ZrO<sub>2</sub>–Al<sub>2</sub>O<sub>3</sub>–Fe<sub>3</sub>O<sub>4</sub>as green solid acid catalysts in organic reactions
作者:Anqi Wang、Xiang Liu、Zhongxing Su、Huanwang Jing
DOI:10.1039/c3cy00572k
日期:——
A series of magnetic solid acid nano-catalysts were designed and prepared through a facile co-precipitate approach. The original nanocomposites ZrO2âAl2O3âFe3O4 were characterized by means of ICP-AES, BET, XRD, TEM, HRTEM, VSM, FT-IR, NH3-TPD and TG. Their catalytic behaviours were investigated via esterification, the synthesis of bis-indolylmethanes, Hantzsch reaction, Biginelli reaction and Pechmann reaction. In all of these organic reactions, the corresponding products were obtained in moderate to excellent yields. The optimal catalyst was ZAF-16/16, which retained catalytic activity after several recycles.
Here we demonstrate on the synthesis of 3,4-dihydropyrimidin-2-ones (DHPMs) and their derivatives through a three-component condensation reactions of aldehyde, β-ketoester and urea or thiourea using mesoporous aluminosilicate (AlKIT-5) nanocage as catalyst and acetonitrile as solvent under reflux conditions. The catalyst was found to be highly active and selective, affording a high yield of DHPMs.
Anhydrous Magnesium Sulfate Mediated Solvent-Free Synthesis of Dihydropyrimidin-2(1H)-ones at Ambient Temperature
作者:D. M. Pore、U. V. Desai、T. S. Thopate、P. P. Wadgaonkar
DOI:10.1071/ch07097
日期:——
An anhydrous magnesium sulfate mediated solvent-free protocol is described for the synthesis of dihydropyrimidinones (Biginelli compounds) at ambient temperature.
for the one-potsynthesis of dihydropyrimidinones (DHPMs) compounds. Dihydropyrimidinone derivatives were synthesized in good yields using ethyl acetoacetate, aldehyde (aromatic and aliphatic) and urea or thiourea in the presence of ZnO nanoparticles as a catalyst in H2O as solvent at 80 o C. This green chemistry procedure applied to the Biginelli reaction using ZnO nanoparticles as catalyst and illustrated
Calix[8]arene Sulfonic Acid Catalyzed Three-Component Reaction for Convenient Synthesis of 3,4-Dihydropyrimidin-2(1<i>H</i>)-ones/thiones under Ultrasonic Irradiation
for the famous Biginelli reaction. Underultrasonicirradiation, calix[8]arene sulfonic acid could efficiently catalyzed the three-componentreaction of aldehydes with ethyl acetoacetate and urea or thiourea in ethanol to afford the corresponding 3,4-dihydropyrimidin-2(1H)-ones/thiones in 46-93%. The advantages of this method are the easy isolated procedure, short reaction time and low cost of the