Synthesis of piperazine-based benzimidazole derivatives as potent urease inhibitors and molecular docking studies

The development of new bioactive compounds is important for progress in therapeutic research. In the present study, we describe the multistep synthetic approach to develop a library of novel benzimidazole analogs incorporating piperazine rings in order to increase their biological activity. In order to synthesize the desired benzimidazole analogs, the synthesis started with the easily accessible precursors between aniline and chloroacetyl chloride. It proceeded via a series of reactions, such as condensation, cyclization, and N-alkylation. TLC optimized each step, and spectroscopic methods such as CHN, IR, EIMS, ¹H-NMR, and ¹³C-NMR were used to characterize the final products. The urease inhibitory activity of the synthesized compounds was evaluated. It was discovered that almost all compounds were quite effective, even more potent (IC₅₀ = 0.15-12.17 µM) than the standard thiourea (IC₅₀ = 23.11 ± 0.21 µM). The structure-activity relationship (SAR) is also established, which displayed that compound 9 L (IC₅₀ = 0.15 ± 0.09 µM) with -NO₂ substitutions at meta position play a major role in urease inhibition and figure out as the most potent analog of the library. These results were further verified by molecular docking analysis, which indicated favorable binding energies and interactions of the compounds with the urease active site. This study not only depicts the importance of multistep synthesis but also the structure-based modification approach to produce new pharmacophores for therapeutic applications.