Synthesis of mesomeric betaines containing a pyrrolo- or imidazotriaziniumolate system and their cycloaddition with acetylenic dipolarophiles leading to triazocinone derivatives
作者:Norio Sakai、Makoto Funabashi、Takayuki Hamada、Satoshi Minakata、Ilhyong Ryu、Mitsuo Komatsu
DOI:10.1016/s0040-4020(99)00843-1
日期:1999.11
containing a cyclic azomethine imine unit were synthesized and their cycloaddition with acetylenic dipolarophiles were examined. Unexpectedly the cycloaddition of the betaines with electron-deficient dipolarophiles gave ring-expanding adducts having a triazocinone structure. With electron-rich dipolarophiles such as ynamines, the reactions proceeded more readily leading regioselectively to the same type of triazocinones
合成了一系列含有环偶氮甲亚胺亚胺单元的2-取代的介观甜菜碱,并研究了它们与炔属双极性亲和剂的环加成反应。出乎意料的是,甜菜碱与缺乏电子的偶极亲和剂的环加成反应产生具有三唑啉酮结构的扩环加合物。使用富电子的偶极亲和剂(例如ynamines),反应更容易进行,从而以几乎定量的产率在区域选择性地导致相同类型的三唑烷酮。特别是在咪唑基甜菜碱和氨基胺的情况下,环加成反应在室温下进行,从而以优异的收率独家提供了起始的环加合物。发现分离的三环前体在加热至60℃时定量地重排成最终产物。