Clay-Supported Cu(II) Catalyst: An Efficient,Heterogeneous, and Recyclable Catalyst for Synthesis of 1,4-Disubstituted 1,2,3-Triazoles from Alloxan-Derived Terminal Alkyne and Substituted Azides Using Click Chemistry

A novel series of alloxan-derived 1,4-disubstituted 1,2,3-triazoles was synthesized in excellent yields under catalytic conditions using a click reaction strategy through 1,3-dipolar cycloaddition. Their structures have been ascertained on the basis of spectroanalytical and elemental analysis data. Synthesis of hybrid compounds with varying substitutions in the triazole ring was achieved by reaction between alloxan-derived terminal alkyne and a pertinent azide derivative in the presence of clay-Cu(II) as the catalyst in methanolic medium. Also, comparative evaluation of various catalytic systems viz., CuI, CuSO₄, CuI-zeolite, K10Ti, and clay-Cu(II)] was investigated. Of these catalytic systems, clay-Cu(II) was observed to be the best. The catalyst was recyclable for several runs without showing significant loss in its activity. The good selectivity, cost-efficiency, short reaction time, milder reaction conditions, and simple workup procedure are the added salient features of this synthetic protocol.