Synthesis of Schiff’s Bases of 1,2,4-Triazole Derivatives under Microwave Irradiation Technique and Evaluation of their Anti-diabetic Activity

Background: Schiff bases play a key role in the generation of a large number of biologically active compounds via cycloaddition, replacement, and ring closure reactions. Objective: The objective of this study is to optimize the purity and yield of the product, improve the reaction time, and make the reaction more eco-friendly with the help of microwave-assisted organic synthesis. Methods: New series of Schiff’s bases of triazole derivatives were achieved via multicomponent reactions. The starting material benzohydrazide 1 was obtained by esterification of benzoyl chloride with methanol in the presence of concentrated sulphuric acid, followed by the reaction with hydrazine hydrate. Benzohydrazide was allowed to react with carbon disulphide in ethanolic potassium hydroxide solution to yield potassium dithiocarbazinate 2, which undergoes cyclization by reacting with hydrazine hydrate to afford 4-[amino]-5-phenyl-4H-1,2,4-triazole-3-thiol (3). Further, various Schiff’s bases, 4a-f, were obtained by reacting 1,2,4-triazole-3-thiol with different substituted benzaldehydes under microwave irradiations as a green and eco-friendly energy source. Results: The structures of the newly synthesized compounds were elucidated in accordance with their spectral data and elemental analysis. Conclusion: The obtained compounds exhibited significant in vivo anti-diabetic activity as compared to the standard drug Metformin. The anti-diabetic effect was investigated by using the Alloxan-induced diabetic model.