Hydrothermally Developed ZnC2O4.2H2O Nanocrystals as Efficient Copper‐free Catalyst for the Synthesis of 1,4‐Disubstituted 1,2,3‐Triazoles in Water

In this work, we report the synthesis of nanostructured ZnC2O4.2H2O with irregular sheet‐like morphology using a simple hydrothermal procedure. The as‐synthesized ZnC2O4.2H2O nanocrystal (ZnC2O4 NC) is very stable and therefore, explored for the first time as highly efficient recyclable catalyst for the azide‐alkyne cycloaddition (AAC) reaction. Our catalytic protocol is highly efficient and amenable to a variety of aromatic/aliphatic azide and alkyne substrates under mild reaction condition to afford regioselective 1,4‐disubstituted 1,2,3‐triazoles with good to excellent yields. Also, for the one pot synthesis of desired products, the developed method is exceedingly sustainable where azides are formed in‐situ from their respective precursors. Our catalytic results outperformed most of the reported state‐of‐the‐art works involving copper free nanoparticulate and zinc‐based catalysts. All the original features of the recovered catalyst remained intact after 5th catalytic cycle which clearly suggests the efficiency of the Zn‐based stable nanostructured material as alternative copper free catalysts for AAC reactions. The developed methodology could be extended for gram‐scale synthesis of 1,2,3‐triazoles. Irregular sheet‐like nanocrystalline ZnC2O4.2H2O particles were explored as highly efficient recyclable catalyst in the quantitative synthesis of 1,4‐disubstituted 1,2,3‐triazoles with excellent regioselectivity under mild rection condition.