One‐pot Synthesis of Tetrahydrobenzo[b]pyrans Catalyzed by PEG‐1000 Bridged Primary Amine Functionalized Dicationic Ionic Liquid in Water |
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Authors: | Ying‐Lei Wang Zhuo Li Jun Luo Zu‐Liang Liu |
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Institution: | 1. School of Chemical Engineering, Nanjing University of Science and Technology, Nanjing 210094, China;2. College of Forestry, Henan Agricultural University, Zhengzhou 450002, China |
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Abstract: | A novel poly (ethylene glycol) bridged primary amine functionalized dicationic ionic liquid (PA‐PEG1000‐DIL]BF4]) was synthesized and characterized by 1H‐NMR, 13C‐NMR, FT‐IR and ESI‐MS. The thermal gravimetric analysis (TGA) and differential scanning calorimetry (DSC) analysis indicated the high thermal stability of PA‐PEG1000‐DIL]BF4]. It was used as an efficient and recyclable catalyst for the synthesis of substituted tetrahydrobenzob]pyrans through a one‐pot three‐component condensation of aromatic aldehydes, malononitrile and dimedone in 86% ~ 96% yields within 10 ~ 30 min in water. This method offers several advantages such as mild reaction conditions, simple operation and environmental friendliness. Furthermore, the catalyst could be easily recovered and reused for at least five runs without obvious loss of catalytic activity. |
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Keywords: | Primary amine Poly(ethylene glycol) Ionic liquid Tetrahydrobenzo[b]pyran Water |
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