Simple and Highly Efficient Synthesis of 3,5-Disubstituted Isoxazoles Using Cu/Graphene/Clay Nanohybrid as a New Heterogeneous Nano Catalyst

Abstract

A facile and convenient protocol for ‘click’ cycloaddition of structurally diverse alkynes with in situ generated nitrile oxides catalysed by Cu/aminoclay/reduced graphene oxide nanohybrid (Cu/AC/r-GO nanohybrid) as a highly efficient heterogeneous nano-catalyst is described. In this method, Cu/AC/r-GO nanohybrid catalyses the 1,3-dipolar cycloaddition of alkynes and nitrile oxides in the presence of NaHCO₃ in H₂O/THF (50:50, V/V) to afford the corresponding 3,5-disubstituted isoxazoles. The Cu/AC/r-GO nanohybrid is a low cost, non-hygroscopic, chemically and thermally stable catalyst that can be reused for many consecutive reaction runs without significant loss in its reactivity.