2-(2′-Pyridyl) benzimidazole derivatives and their urease inhibitory activity

Pyridyl-benzimidazole analogues 1–11 with variable substituent on phenyl ring of phenacyl moiety were synthesized and evaluated for their urease inhibitory activity. The compounds exhibited urease inhibition with IC50 between 19.22 and 77.31 µM. Compounds 4 (IC50 = 19.22 ± 0.49 µM) showed a urease inhibition comparable to thiourea (IC50 = 21.00 ± 0.01 µM) and twofold more active than acetohydroxamic acid (IC50 = 42.00 ± 1.26 µM) (standards), respectively. Moreover, compounds 5 (IC50 = 21.55 ± 0.36 µM), 1 (IC50 = 24.37 ± 0.41 µM), 7 (IC50 = 25.44 ± 0.19 µM), 6 (IC50 = 27.62 ± 0.25 µM), 3 (IC50 = 31.32 ± 0.75 µM), 8 (40.88 ± 0.36 µM) and 9 (41.22 ± 0.42 µM) also exhibited excellent activities when compared to the standards. Compounds 2 (IC50 = 65.46 ± 0.75 µM), 10 (68.99 ± 0.33 µM) and 11 (77.31 ± 0.51 µM) showed a moderate activity. The size of the substituents and their electron donating or withdrawing affects as well as their position on phenyl apparently modulates the enzyme inhibitory activity.