Synthesis of 5-substituted-1H-tetrazoles by lemon juice as a homogeneous and natural catalyst under green reaction conditions

Tetrazole, as a heterocyclic compound, exhibits a wide spectrum of applications in various industries. This research focuses on utilizing a natural catalyst in the synthesis of tetrazole derivatives. Leveraging the acidic nature of lemon juice (LJ), we employed it as a potential catalyst in the synthesis of 5-substituted-1H-tetrazole. LJ would act as the reaction medium as well. This synthesis involves the cycloaddition reaction (3 + 2) of sodium azide to benzonitrile under solvent-free conditions. Optimization of the reaction conditions including temperature, reaction time, and solvent type was tuned towards the highest yield considering the mild reaction time. The best product yield (97 %) was obtained at 90 °C, 40 min, in the absence of additional solvent. Various benzonitrile derivatives were examined at the optimized reaction condition.