One‐pot synthesis of trifluoromethylated benzimidazolines catalyzed by phosphotungstic acid with a low catalyst loading |
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| Authors: | Xue Feng Tao Yang Xing He Bing Yu Chang‐Wen Hu |
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| Institution: | 1. Key Laboratory of Cluster Science of Ministry of Education, Beijing Key Laboratory of Photoelectronic/Electrophotonic, School of Chemistry and Chemical Engineering, Beijing Institute of Technology, Beijing, P. R. China;2. College of Chemistry and Molecular Engineering, Zhengzhou University, Zhengzhou, P. R. China |
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| Abstract: | The inexpensive Keggin‐type polyoxometalate, i.e. H3PW12O40 was found to be an effect catalyst for the condensation‐cyclization reaction of 1,2‐phenylenediamines and trifluoromethyl ketones to synthesize trifluoromethylated heterocycles, including benzimidazolines, benzoxazolines and benzothiazolines. Only 1 mol% of H3PW12O40 was required in this work, and the synergistic effect of proton and polyanion was vital for the reaction. Significantly, the POM catalyst could be easily recovered by using a biphasic solvent system (H2O/toluene, V/V = 1:5), and reused at least for four times without significant loss in activity. |
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| Keywords: | condensation one‐pot reaction polyoxometalate synergistic effect trifluoromethylated heterocycles |
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