Heterogeneous V2O5/TiO2-Mediated Photocatalytic Reduction of Nitro Compounds to the Corresponding Amines under Visible Light

The hydrogenation of nitro compounds to their corresponding amines is developed using a heterogeneous and recyclable catalyst (V₂O₅/TiO₂) under irradiation of blue LED (9 W) at ambient temperature. Hydrazine hydrate is used as a reductant and ethanol is used as a solvent, facilitating green, sustainable, low-cost production. The synthesis of 32 (hetero)arylamines and their pharmaceutically relevant molecules (five) are described. Significant features of the protocol include catalyst recyclability, green solvent, ambient temperature, and gram-scale reactions. Among the other aspects studied are ¹H-NMR-assisted reaction progress monitoring, control experiments for mechanistic studies, protocol applications, and recyclability studies. Furthermore, the developed protocol enabled wide functional group tolerance, chemo-selectivity, high yield, and low-cost, sustainable, and environmentally benign synthesis.