Synthesis and antioxidant properties of novel N-methyl-1,3,4-thiadiazol-2-amine and 4-methyl-2 H-1,2,4-triazole-3(4 H)-thione derivatives of benzimidazole class

• Published in: Bioorganic & medicinal chemistry Vol. 16; no. 8; pp. 4294 - 4303
• Main Authors: Kuş, Canan, Ayhan-Kılcıgil, Gülgün, Özbey, Süheyla, Kaynak, F. Betül, Kaya, Melek, Çoban, Tülay, Can-Eke, Benay
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 2008
• Subjects: Antioxidant; N-Methylthiadiazolyl-benzimidazoles; N-Methylthiosemicarbazides; N-Methyltriazolylbenzimidazoles; X-ray structure analysis; N-Methylthiadiazolyl-benzimidazoles; N-Methylthiosemicarbazides; X-ray structure analysis; Antioxidant; N-Methyltriazolylbenzimidazoles
• ISSN: 0968-0896; 1464-3391
• DOI: 10.1016/j.bmc.2008.02.077

Nowadays antioxidants arouse researchers’ interest in both medical plants and synthetic compounds. In this study, we synthesized some novel benzimidazole compounds bearing alkyl (methyl) group at the 4th position of triazole ring and at the 5th position of thiadiazole ring instead of aryl group. Some novel 1-methyl-4-(2-(2-substitutedphenyl-1 H-benzimidazol-1-yl)acetyl)thiosemicarbazides ( 16a– 20a), 5-[(2-(substitutedphenyl)-1 H-benzimidazol-1-yl)methyl]- N-methyl-1,3,4-thiadiazol-2-amines ( 17b– 20b), and 5-[(2-(substitutedphenyl)-1 H-benzimidazol-1-yl)methyl-4-methyl-2 H-1,2,4-triazole-3(4 H)-thiones ( 16c– 20c) were synthesized and tested for antioxidant properties by using various in vitro systems. Compounds 16a– 20a were found to be a good scavenger of DPPH radical (IC 50, 26 μM; IC 50, 30 μM; IC 50, 43 μM; IC 50, 55 μM; IC 50, 74 μM, respectively) when compared to BHT (IC 50, 54 μM). Noteworthy results could not be found on superoxide radical. Compound 19b, which is the most active derivative inhibited slightly lipid peroxidation (28%) at 10 −3 M concentration. Compound 17c inhibited the microsomal ethoxyresorufin O-deethylase (EROD) activity with an IC 50 = 4.5 × 10 −4 M which is similarly better than the specific inhibitor caffeine IC 50 = 5.2 × 10 −4 M.