Laboratory of Catalysis, Institute of Chemistry , University of Brasília (IQ-UnB) , Brasilia 70910-900 , Brazil.
Institute of Chemistry , Universidade Estadual de Campinas (Unicamp) , 13083970 , Campinas , SP , Brazil.
J Org Chem. 2018 Apr 6;83(7):4044-4053. doi: 10.1021/acs.joc.8b00472. Epub 2018 Mar 29.
The current manuscript describes the use of a heteropolyacid-containing task-specific ionic liquid, supported in imidazolium-based ionic liquids, as the catalyst for an efficient multicomponent synthesis of hexahydroimidazo[1,2-α]pyridine derivatives. The reactions conditions were fully optimized, and the bridgehead nitrogen heterocycle derivatives could be obtained in just 1 h exclusively as a single isomer ( trans). Single crystal X-ray analysis confirmed the trans derivative as the only isomer. The mechanism of the reaction was investigated by ESI(+)-MS(/MS), and the use of the elegant charge-tag strategy allowed a catalytic cycle to be proposed for the current transformation and revealed the possibility of at least two reaction pathways. One derivative bearing a coumarin scaffold was synthesized, and its fluorescent properties allowed it to be tested as a probe for live-cell imaging experiments with a preference for mitochondria.
本文描述了使用含杂多酸的功能化离子液体作为催化剂，在基于咪唑的离子液体中支持，用于高效合成六氢咪唑并[1,2-α]吡啶衍生物的多组分反应。对反应条件进行了全面优化，仅需 1 小时即可以单一异构体（反式）获得桥头氮杂环衍生物。单晶 X 射线分析证实反式衍生物是唯一的异构体。通过 ESI(+)-MS(/MS) 研究了反应机理，使用巧妙的电荷标记策略，可以提出当前转化的催化循环，并揭示了至少两种反应途径的可能性。合成了一个带有香豆素支架的衍生物，并对其荧光性质进行了测试，作为活细胞成像实验的探针，对线粒体有偏好。
