Synthesis and Antioxidative Potency of Novel Amidino Substituted Benzimidazole and Benzothiazole Derivatives

Abstract

Herein we present the synthesis of versatile amidino substituted benzothiazole 3-10 and benzimidazole 12-19 derivatives substituted with the variable number of hydroxy and methoxy groups. Furthermore, the synthesized compounds were explored for their antioxidative activity in vitro by using three biological assays, namely DPPH, ABTS and FRAP. The obtained results indicated that the variable number of hydroxy groups together with the type of the amidino substituent strongly influenced the antioxidative activity and reducing power of tested compounds. The most promising antioxidative activity showed trihydroxy substituted compounds 6, 10, 15 and 19. In general, it was noticed that unsubstituted amidino group induced the more pronounced activity in comparison to derivatives bearing 2-imidazolinyl group.

Synthesis and Antiproliferative activity in vitro of Amidino Substituted 2-phenylbenzazoles

“…NMR analysis based on the values of H-H coupling constants and chemical shifts in the 1 H spectra confirmed the structures of compounds. Furthermore, 13 C NMR chemical shifts were consistent with the suggested structures.…”

“…chloride 6 [13] Using above described method from 2,4-dihydroxybenzaldehyde 1d (0.069 g, 0.5 mmol) and 2-amino-5amidiniumbenzenethiolate 2a (0.084 g, 0.5 mmol) was obtained 0.083 g (52 %) of pale yellow solid; mp > 300 °C. 1…”

“…The crude product was then filtered off, washed with diethyl ether and recrystallized from ethanol to obtain pure compounds 12-19. [17] 5 6 Amidinium-2-(2,4-dihydroxyphenyl)benzimidazole chloride 15 [13] Using above described method from 2,4-dihydroxybenz-aldehyde 1d (0.100g, 0.7 mmol), 4-amidinium-1,2-phenylenediamine 11a (0.135 g, 0.7 mmol) and p-benzoquinone (0.078 g, 0.7 mmol) in absolute ethanol (3.5 mL) was obtained 0.023 g (10.4 %) of violet solid; mp > 300 °C; 1…”

“…[1,2] These nitrogen and sulphur-containing heterocycles become unavoidable substructures in the rational design of novel drugs. [3,4] These derivatives has been proven to possess important role in the structure of various biologically important natural and synthetic molecules, while among their versatile pharmacological features, the most important ones are antimicrobial, [5,6] antitumor, [7,8] antiviral, [9] anti-inflammanory, [10] antihistaminic, [11] antioxidant, [12,13] etc. Importantly, since benzimidazoles are bioisosteres of purines, which offer the possibility of interactions with biomolecules from the living systems, benzimidazole derivatives play a crucial role in the function of many biologically important molecules like DNA, RNA or different proteins included in numerous metabolic processes in living organisms.…”

Experimental and Computational Study of the Antioxidative Potential of Novel Nitro and Amino Substituted Benzimidazole/Benzothiazole-2-Carboxamides with Antiproliferative Activity

“…Our focus was to inspect the effect of the number of methoxy groups and the type of amidine substituent on the antioxidative and antiproliferative features, with an important conclusion that systems with the highest antioxidant activities are less cytotoxic and do not inactivate the cancer cell line proliferation. We also showed the antioxidative potency of 2-aryl substituted benzimidazoles and benzothiazoles having a flexible number of hydroxy groups and different types of amidino substituents, which strongly affected their antioxidative activity and reducing power [22]. Salicylanilide and benzamide derivatives, besides a broad range of multipurpose biological activities, have also been studied as systems with good antioxidative potential [23].…”