Department of Chemistry, Indian Institute of Technology Hyderabad, Kandi, Sangareddy 502285, Telangana, India.
Org Biomol Chem. 2020 Jun 10;18(22):4231-4237. doi: 10.1039/d0ob00805b.
Amidines are a preeminent group of organic compounds having wide applications in various industries. Here, we have developed a simple one-step reaction protocol for the facile synthesis of N-arylamidines catalysed by calcium bis(hexamethyldisilazide) [Ca{N(SiMe3)2}2(THF)2]. The amidine synthesis was readily achieved from organic nitriles and amines which provided a broad substrate scope ranging from electron-withdrawing to electron-donating substitutions as well as heterocyclic substitution. The reaction was carried out in a solvent-free medium under ambient conditions. The nucleophilic addition of aromatic amines to aryl nitriles led to good to excellent yields of the corresponding amidines. The reactivity of the amidines was further examined and the respective urea derivatives were achieved in excellent yields. The plausible mechanism involves the generation of an active calcium amido pre-catalyst that helps in the activation of nitriles in the reaction course.
脒类是一类卓越的有机化合物，在各个行业中有着广泛的应用。在这里，我们开发了一种简单的一步反应方案，通过钙双（六甲基二硅氮烷）[Ca{N(SiMe3)2}2(THF)2]催化，可轻松合成 N-芳基脒类化合物。该脒类合成方法可轻松实现由有机腈和胺的反应，提供了广泛的底物范围，包括吸电子和供电子取代基以及杂环取代基。反应在无溶剂的条件下，在环境条件下进行。芳基胺的亲核加成到芳基腈上，得到相应的脒类化合物，产率良好至优秀。进一步考察了脒类的反应性，以优异的产率得到了相应的脲衍生物。推测的机理涉及活性钙酰胺前催化剂的生成，它有助于在反应过程中活化腈。
