Synthesis and urease inhibition activities of some new schiff bases benzimidazoles containing thiophene ring

Abstract

Objective: Schiff bases are significant pharmacophores and show varied biological applications such as antiurease, antidiabetic, antioxidant, antifungal, antibacterial, and anticancer. In this study, new Schiff bases derivatives of benzimidazole containing thiophene ring were synthesized and characterized by IR, 1H NMR, and 13C NMR spectroscopic methods, and elemental analysis data. Methods: Novel Schiff bases were synthesized in high yield and purity. Their anti-urease activities were evaluated by the Weatherburn method against Jack bean urease and compared with thiourea (0.217 +/- 0.16 mu M) used as a standard. Results and Discussion: All new Schiff bases have antiurease activity with IC50 values ranging from 0.42 +/- 0.03 and 0.10 +/- 0.25 mu M. N '-[(2-hydroxy5-methylphenyl)methylidene]-2-[5,6-dichloro-2-(thiophen-2-ylmethyl)-1H-benzimidazol-1-yl]acetohydrazide (IVf) has the best inhibition activity with 0.10 +/- 0.25 mu M IC50 value. Also, N '-[furan-2-ylmethylidene]-2-[5,6dichloro-2-(thiophen-2-ylmethyl)-1H-benzimidazol-1-yl]-acetohydrazide (IVl) and N '-[(5-chloro-2-hydroxyphenyl)methylidene]-2-[5,6-dichloro-2-(thiophen-2-ylmethyl)-1H-benzimidazol-1-yl]acetohydrazide (IVg) have antiurease activities better than the standard Thiourea (0.217 +/- 0.160 mu M). Conclusions: The dichlorobenzimidazoles derivatives of Schiff bases have excellent antiurease inhibition activity. The thiophene ring at 2-positions of benzimidazole and dichloro atoms has a positive effect on inhibition activity of urease.