Magnetic carbon nanotube as a highly stable support for the heterogenization of InCl₃ and its application in the synthesis of isochromeno[4,3‐c]pyrazole‐5(1H)‐one derivatives

Abstract

In the present study, a novel magnetically retrievable catalytic system involving indium nanoparticles on magnetic carbon nanotube (Fe3O4‐CNT‐In) was synthesized and characterized using various techniques, such as Fourier transform‐infrared, thermogravimetric analysis, energy‐dispersive X‐ray analysis, vibrating‐sample magnetometry1, X‐ray diffraction, field emission‐scanning electron microscopy and inductively coupled plasma‐optical emission spectrometry. The catalytic activity of the synthesized nanocatalyst was evaluated in green synthesis of isochromeno[4,3‐c]pyrazole‐5(1H)‐one derivatives from the reaction of ninhydrin and arylhydrazones under solvent‐free conditions. The catalyst was magnetically separated from the reaction mixture using an external magnet and recovered for five cycles without an appreciable decrease in its catalytic efficiency. Performing the reactions in environmentally friendly and affordable conditions, the low catalyst percentage, high yield of products, short reaction times, large substrate scope and easy work‐up are the merits of this protocol. Furthermore, four of the synthesized isochromeno[4,3‐c]pyrazole‐5(1H)‐one derivatives are also new.

Solvent-free synthesis of propargylamines: an overview

“…Propargylamines were synthesized by A 3 coupling of aldehydes and amines with phenylacetylene. 89 Reactions carried out at 80 °C for 2 h under solvent-free conditions with 0.02 g CNT–Fe 3 O 4 –fibroin–Ag as catalyst was found to be optimum ( Scheme 47 ). The catalyst was retrieved eight times without losing the catalytic activity.…”

Development of Magnetizable, Nickel–Ferrite-Decorated Carbon Nanocomposites as Hydrogenation Catalyst for Aniline Synthesis

“…However, by combining carbon carriers with magnetic particles, the catalytic system could be easily separated while the carbon continues to exert its beneficial effects. A similar magnetically retrievable system was prepared by Akbarzadeh et al, in which magnetic nanoparticles were synthetized on the surfaces of carbon nanotubes [30]. The composite was used for the synthesis of isochromeno [4,3-c]pyrazole-5(1H)-one, providing a product yield of more than 90%.…”