Synthesis of Pyrano [2,3-c] Pyrazole Derivatives Using a Novel Ionic-Liquid Based Nano-Magnetic Catalyst (Fe<sub>3</sub>O<sub>4</sub>@SiO<sub>2</sub>@(CH<sub>2</sub>)<sub>3</sub>NH@CC@Imidazole@SO<sub>3</sub>H<sup>+</sup>Cl<sup>−</sup>)
Tahereh Akbarpour, Jaber Yousefi Seyf, Ardeshir Khazaei, Negin Sarmasti
Abstract
The current study is a molecular engineering approach designed for synthesize an ionic-liquid-based nano-magnetic solid acid heterogeneous catalyst, namely Fe3O4@SiO2@(CH2)3NH@CC@Imidazole@SO3H. Following the synthesis of the mentioned catalyst, various techniques were used to characterize, including Infrared (IR), Field Emission Scanning Electron Microscopy (FESEM) and Transmission Electron Microscopy (TEM), Energy-dispersive X-ray spectroscopy (EDX), EDX elemental mapping, Thermal gravimetric analysis (TGA) and Differential thermal analysis (DTA), and Vibrating Sample Magnetometer (VSM). The activity of the as-synthesized catalyst was evaluated in the synthesis of pyrano [2,3-c] pyrazole derivatives. It can easily be recovered using an external magnet and used repeatedly. The FTIR proved the stability of the as-synthesized catalyst even after five recovery steps. The most exciting finding was that pyrano [2,3-c] pyrazole derivatives could be produced in a short time and high yield (56–98%). The systematic design of experiment (DOE), finally, was applied to optimize the reaction condition.