The first urea-based ionic liquid-stabilized magnetic nanoparticles: an efficient catalyst for the synthesis of bis(indolyl)methanes and pyrano[2,3-d]pyrimidinone derivatives

Urea-based ionic liquid stabilized on silica-coated Fe3O4 magnetic nanoparticles, {Fe3O4@SiO2@(CH2)(3)-Urea-SO3H/HCl}, as an unexceptionable and smooth releasing urea fertilizer in alkali soils was synthesized and fully characterized using Fourier transform infrared, UV-visible and energy-dispersive X-ray spectroscopies, X-ray diffraction, scanning and transmission electron microscopies, atomic force microscopy and thermogravimetric analysis. The nanostructure catalyst as a novel, green and efficient catalyst was applied for the synthesis of bis(indolyl)methane derivatives via the condensation reaction between 2-methylindole and aldehydes at room temperature under solvent-free conditions. Also, pyrano[2,3-d]pyrimidinone derivatives were prepared in the presence of the nanomagnetic urea-based catalyst by the one-pot three-component condensation reaction of 1,3-dimethylbarbituric acid, aldehydes and malononitrile under solvent-free conditions at 60 degrees C. To the best of our knowledge, this is the first report of the synthesis of urea-based ionic liquid stabilized on silica-coated Fe3O4 magnetic nanoparticles. So the present work can open up a new and promising insight in the course of rational design, synthesis and applications of task-specific fertilizer-based nanomagnetic ionic liquids with desirable properties as unexceptionable substances for sustainable processes. Copyright (C) 2016 John Wiley & Sons, Ltd.