Synthesis of polyazaheterocycles by Michael addition of CH acids to ?,?-unsaturated nitriles. Synthesis of pyrido[1,2-a]benzimidazole and pyrimido[5?,4?: 5,6]pyrido[1,2-a]benzimidazole derivatives
摘要:
Addition of 1H-benzimidazole-2-carbonitrile (1) to arylidenemalononitrile (2) gave 1-amino-3-aryl pyrido[1,2-a]benzimidazole-2,4-dicarbonitrile (3), 2-aryl-benzimidazole (4) and 1H-benzimidazole-2-acetonitrile, alpha-(arylmethylene) (5). Compounds (3) reacted with formamide yielding 4-amino-5-aryl pyrimido[5',4': 5,6]pyrido[1,2-a]benzimidazole (6).