A direct annulation reaction of N-benzimidazolyl amidines with aldehydes has been established and allows the synthesis of ortho-fused 1,3,5-triazine derivatives. The N-benzimidazolyl amidine substrates are readily accessible by the addition of 2-aminobenzimidazoles to the corresponding nitriles. In the presence of molecular iodine and copper iodide, cyclization of benzimidazolyl amidines with various aldehydes in toluene under reflux followed by oxidation with 2,3-dichloro-5,6-dicyano-1,4-benzoquinone (DDQ) gives the corresponding products. In this reaction, iodine acts more as a Lewis acid catalyst than as an oxidant. This synthetic process is insensitive to air and operationally simple, and provides facile access to a variety of novel 1,3,5-triazino[1,2-a]benzimidazoles and related heterocycles.

中文翻译：

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碘/铜（I）催化的N-苯并咪唑基Am与醛的环化反应，用于邻位融合的1,3,5-三嗪的合成

已经建立了N-苯并咪唑基am与醛的直接环化反应，并允许合成邻位熔融的1,3,5-三嗪衍生物。所述Ñ -benzimidazolyl脒底物是通过加入2-氨基苯并咪唑，以相应的腈容易接近。在分子碘和碘化铜的存在下，苯并咪唑基am与甲苯中的各种醛在回流下环化，然后用2,3-二氯-5,6-二氰基-1,4-苯醌（DDQ）氧化，得到相应的产物。在该反应中，碘起路易斯酸催化剂的作用比起氧化剂起更多的作用。这种合成工艺对空气不敏感，操作简单，可轻松接触各种新颖的1,3,5-三嗪[1,2-a ]苯并咪唑及相关杂环。