Green aqueous synthesis and antimicrobial evaluation of 3,5-disubstituted 1,2,4-triazoles

An eco-friendly and simple procedure was proposed for the synthesis of 3,5-disubstituted 1,2,4-triazoles by optimized reaction of benzamidine hydrochloride and various aryl hydrazides. H2O and K2CO3 were applied as green and available solvent and base, respectively. The products were generated in good to high yields in one step and sufficient purity after a simple workup. The designed process is applicable to other organic syntheses especially from poorly water-soluble reactants such as hydrazines or hydrazides. Inhibitory activity of all prepared derivatives was evaluated against 10 pathogenic bacteria strains including both Gram-positive and Gram-negative, as well as 2 mold and 1 yeast strains. The prepared derivatives showed good antimicrobial activities. 1,2,4-Triazoles containing 2-hydroxynaphthalen-3-yl and 5-chlorothiophen-2-yl substituents at position 3 showed the best antifungal and antibacterial properties, respectively.