1Department of Pharmaceutics and Pharmaceutical Technology, Faculty of Pharmacy, University of Petra, Amman, Jordan
2Department of Medicinal Chemistry and Pharmacognosy, Faculty of Pharmacy, University of Petra, Amman, Jordan
3College of Pharmacy, Al-Ain University of Science and Technology, Al-Ain, UAE
*Corresponding e-mail: zeldeen@uop.edu.jo
Online published on 19 November, 2018.
The aim of this study was to design and synthesize new amino acetylenic 5-ethoxy-2-mercaptobenzimidazole derivatives as potential antimicrobial agents.
New series of 5-ethoxy-2-{[4-(t-amino-1-yl) but-2-yn-1-yl] sulfanyl}-1H-benzimidazole derivatives were synthesized by Mannich reaction, and investigated for their antimicrobial activity. Their structural confirmation was confirmed using the EuroEA elemental analyzer, and by Bruker FTIR, 1H-NMR, 13C-NMR. The antimicrobial activity was evaluated in-vitro by agar diffusion method and broth dilution test. The minimum inhibitory concentration and the minimum bactericidal/fungicidal concentration were determined.
The IR, 1H-NMR, 13C-NMR and elemental analysis were consistent with the assigned structures. All new amino acetylenic 5-Ethoxy-2-mercaptobenzimidazole derivatives showed good antibacterial activity against Bacillus subtilis with minimum inhibitory concentration value of 31.25 μg/ml except 5-ethoxy-2-{[4-(2-methylpiperidin-1-yl) but-2-yn-1-yl]sulfanyl}-1H-benzimidazole which showed value of 250 μg/ml, 5-ethoxy-2-{[4-(2, 6-dimethylpiperidin1-yl)but-2-yn-1-yl]-sulfanyl}-1H-benzimidazole showed excellent antifungal activity against Candida albicans with the lowest minimum inhibitory concentration value of 31.25 μg/ml.
The antimicrobial results promoted our interest to carry out further structural modifications, to enhance both antibacterial and antifungal activities, and their selectivity.
5-ethoxy-2-mercaptobenzimidazole, Aminoacetylenic, Mannich reaction, Alkylation
