Fabrication of Copper(II)-coated Magnetic Core-shell Nanoparticles an Engineered Nano-magnetic Catalyst for the Synthesis of Pyrano Pyrazole and Pyrazole Derivatives

Pyrano[2,3-c]pyrazole and 5-amino-1H-Pyrazole-4-carbonitrile derivatives were used in the presence of new copper(II)-coated magnetic core-shell nanoparticles Fe3O4@SiO2@Si(OEt)(CH2)(3)@melamine@TC to synthesize an engineered nanomagnetic catalyst in a mild green environment. The synthesized nanocatalyst was well characterized using different techniques. Fe3O4@SiO2@Si(OEt)(CH2)(3)@melamine@TC@Cu(OAc)(2) is an environmentally friendly procedure to synthesize some novel Pyrano[2,3-c]pyrazole and 5-amino -1H-Pyrazole-4-carbonitrile. Relevant products were produced in green conditions with high to excellent yields. Interestingly, the catalyst can be easily separated from the reaction medium by an external magnet and can subsequently be used for successive reaction cycles (at least four times) without a significant reduction in catalytic activity. Energy dispersive X-ray analysis (EDX) was taken from the recovery catalyst for further investigation. The results showed no significant change in the percentage of synthesized catalyst elements. In this study, reaction conditions, i.e. the effect of temperature and amount of catalyst, were optimized using a systematic approach, namely, the design of experiment (DoE). The structures of the synthesized Pyrano[2,3-c]pyrazole and 5-amino-1H-Pyrazole-4-carbonitrile compounds were confirmed by H-1 NMR, C-13 NMR, and FT-IR spectra.