Novel Mannich Base Derivatives: Synthesis, Characterization, Antimicrobial and Antioxidant Activities

In this study, 3-alkyl(aryl)-4-(4-ethylbenzylidenamino)-4,5-dihydro-1H-1,2,4-triazol-5- ones 2 were synthesized as explained in the literature. Then, the Schiff bases 2 were treated with morpholine/ N-methylpiperazine/ 3-methylpiperidine/ 4-piperidinecarboxamide in the presence of formaldehyde according to the Mannich reaction to synthesize novel Mannich bases 3, 4, 5, and 6 types, respectively. The structural analyses of 24 newly synthesized compounds were characterized using proton/ carbon 13 nuclear magnetic resonance (1H/ 13C-NMR), Infrared (IR) spectoscopic techniques. In addition, the antimicrobial activity of the compounds was determined on six bacteria by using the agar well diffusion method. The most effective results against gram positive and negative bacteria were observed in 6(a-d) and 6f compounds. Also, the antioxidant capacities of the substances were investigated by three different methods (DPPH, reducing power, metal chelation). All compounds 3-6(a-f) showed a metal chelating effect.