Design, Synthesis, and Biological Evaluation of 1,2,4-Triazole Derivatives as Potential Antimicrobial Agents

Abstract

In this study, we aimed to develop new biologically active compounds with antibacterial properties. 4-amino-5-methyl-2H-1,2,4-triazol-3(4H)-one (1) was converted to the corresponding Schiff bases (2) with the reaction with a 4-anis aldehyde. Acetic acid ethyl esters containing [1,2,4] triazole ring (3) were synthesized by the condensation of compounds (2) with ethyl bromoacetate in basic media. The reaction of compounds (3) with hydrazine hydrate led to the formation of acid hydrazides (4). The reaction of hydrazide (4) with phenyl isothio - and phenyl isocyanate produced the corresponding carbothioamide (5a) and carboxamide (5b). The basic treatment of carbothioamide (5a) and. carboxamide (5b) produced 1,2,4-triazole (6a, 6b) compounds, respectively. The reactions of ( (6b) with norfloxacin and ciprofloxacin in the presence of formaldehyde afforded the corresponding Mannich bases( 7a, 7b). The structural assignments of the new compounds were based on elemental analysis and spectral (IR, 1H-NMR, and 13C-NMR) data. All newly synthesized compounds were screened for their antimicrobial activity. The in vitro antimicrobial activities of the compounds were evaluated against pathogenic microorganisms, and compounds 7a and 7b were found the most effective antimicrobial activity.