Synthesis, characterization and biological activities of N-Mannich bases and amide compounds developed from heterocyclic triazol-5-one derivatives: 3-alkyl(aryl)-4-amino-4,5-dihydro-1H-1,2,4-triazol-5-ones

Among heterocyclic compounds, 1,2,4-triazoles are valuable chemical structures known for their broad spectrum of biological activities and unique roles in medicinal chemistry applications, especially in drug development processes. In this study, eight 3-alkyl(aryl)-4-amino-4,5-dihydro-1H-1,2,4-triazol-5-one derivatives were synthesized and reacted with 3-nitrobenzoyl chloride to obtain N-[3-alkyl(aryl)-4,5-dihydro-1H-1,2,4-triazol-5-one-4-yl]-3-nitrobenzamide derivatives. Subsequently, the amide derivatives underwent Mannich reactions with formaldehyde and morpholine, resulting in four N-Mannich bases. The structures of a total of 12 synthesized compounds were elucidated using IR, 1H-NMR and 13C-NMR spectroscopic techniques. The biological activities of the compounds were evaluated in vitro. Antioxidant properties were assessed using reducing power, free radical scavenging, and metal chelating activity assays. Additionally, antimicrobial activities were tested against five microorganisms (Bacillus cereus, Klebsiella pneumoniae, Staphylococcus aureus, Serratia marcescens, and Candida albicans) using the agar well diffusion method. The results indicated that the compounds exhibited weak antioxidant activity, while some demonstrated notable antimicrobial effects.