Fourteen novel [1,2,4]triazolo[3,4‐b ][1,3,4]thiadiazine derivatives bearing benzimidazole moiety (7a‐n ) have been synthesized using the one‐pot nitro reductive cyclization method. All the synthesized compounds were confirmed by ¹H nuclear magnetic resonance (¹H NMR), ¹³C NMR, fourier‐transform infrared (FT‐IR), mass spectrum, and elemental analyses. All the title compounds were subjected to in vitro antioxidant activity. The free radical scavenging activity of the compounds was examined using DPPH, nitric oxide, and superoxide radical scavenging methods. The results demonstrated that compound 3‐(2‐(3,4‐dimethoxyphenyl)‐1‐propyl‐1H ‐benzo[d ]imidazol‐5‐yl)‐6‐4‐tolyl‐7H ‐[1,2,4]triazolo[3,4‐b ][1,3,4]thiadiazine (7c ) was potent in scavenging both DPPH and nitric oxide radical with IC₅₀ values of 13.57 and 18.55 μg/ml when compared to the standard with IC₅₀ values of 23.75 and 23.14 μg/ml, respectively, which was due to the presence of electron‐donating groups. The activity was found to decline when electron‐donating groups were replaced by electron‐withdrawing groups. Moderate scavenging activity was observed for the superoxide radical. Structure activity relationship and physiochemical properties were studied for all the derivatives.

中文翻译：

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新型[1,2,4]三唑并[3,4-b] [1,3,4]噻二嗪衍生物嵌入苯并咪唑部分作为有效的抗氧化剂

使用一锅硝基还原环化方法合成了十四种带有苯并咪唑部分（7a-n）的新型[1,2,4]三唑[3,4– b ] [1,3,4]噻二嗪衍生物。所有合成的化合物均通过¹ H核磁共振（¹ H NMR），¹³ C NMR，傅立叶变换红外（FT-IR），质谱和元素分析得到确认。所有标题化合物均经受体外抗氧化活性。使用DPPH，一氧化氮和超氧化物自由基清除方法检查化合物的自由基清除活性。结果表明，化合物3-（2-（3,4-二甲氧基苯基）-1-丙基-1 H-苯并[ d]咪达唑-5-基）-6-4-甲苯基7 H- [1,2,4]三唑[3,4- b ] [1,3,4]噻二嗪（7c）对清除DPPH和一氧化氮自由基的IC ₅₀值为13.57和18.55μg/ ml，而标准品的IC ₅₀值为23.75和23.14μg/ ml，这是由于存在供电子基团。当给电子基团被吸电子基团取代时，活性下降。观察到超氧化物自由基的中等清除活性。研究了所有衍生物的结构活性关系和理化性质。