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Title
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Preparation and characterization of nanomagnetic piperidinium benzene-1,3-disulfonate ionic liquid as a novel, green and heterogeneous catalyst and its use in the synthesis of 1H–pyrazolo[1,2-b]phthalazine-5,10-diones and 1H–pyrazolo[1,2-a] pyridazine-5,8-diones under solvent-free conditions
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Abstract
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The one-pot four-component synthesis of 1H–pyrazolo[1,2-b]phthalazine-5,10-diones and 1H–pyrazolo[1,2-a]pyridazine-5,8-diones was carried out from the reaction between various aldehydes, malononitrile, hydrazine hydrate and phthalic anhydride or maleic anhydride at 110 °C in solvent-free conditions using piperidinium benzene-1,3-disulfonate nanomagnetic ionic liquid (NMIL) as a novel and reusable catalyst. Some advantages of the presented procedure are a significant reduction in cost, effective catalysis and reusability of the catalyst. NMIL was thoroughly characterized using Fourier transform infrared spectroscopy, X-ray diffraction, scanning and transmission electron microscopies, thermogravimetry, derivative thermogravimetry, Brunauer–Emmett–Teller analysis, vibrating sample magnetometry and energy-dispersive X-ray spectroscopy. The technique is developed as a suitable and safe method for the synthesis of 1H–pyrazolo[1,2-b]phthalazine-5,10-diones and 1H–pyrazolo[1,2-a]pyridazine-5,8-diones making use of an efficient and reusable green catalyst. Copyright © 2017 John Wiley & Sons, Ltd.
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