Abstract In this study, 3-alkyl-4-[3-(2-methylbenzoxy)-4-methoxybenzylidenamino]-4,5-dihydro-1H-1,2,4-triazol-5-ones (3) were treated with piperazine in the presence of formaldehyde by the Mannich reaction to obtain novel N,N´-bis-{3-alkyl-4-[3-(2-methylbenzoxy)-4-methoxybenzylideneamino]-4,5-dihydro-1H-1,2,4-triazol-5-on-1-yl-methyl}-piperazines (4). The structures of new compounds were characterized from IR, 1H NMR and 13C NMR spectral data. In addition, in vitro antibacterial activities of the new compounds were evaluated against six bacteria such as Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus, Bacillus subtilis, Bacillus cereus and Klepsiella pneumonia according to agar well diffusion method. Furthermore, the newly synthesized compounds were analyzed for their in vitro potential antioxidant activities in three different methods; including 1,1-diphenlyl-2-picryl-hydrazyl free radical (DPPH.) scavenging, reducing activity by Fe+3 – Fe+2 transformation and ferrous metal (Fe+2) chelating activities.
Keywords: 1,2,4-Triazol-5-one, Mannich base, antimicrobial activity, antioxidant activity.