Heteropolyacid-Containing Ionic Liquid-Catalyzed Multicomponent Synthesis of Bridgehead Nitrogen Heterocycles: Mechanisms and Mitochondrial Staining

J Org Chem. 2018 Apr 6;83(7):4044-4053. doi: 10.1021/acs.joc.8b00472. Epub 2018 Mar 29.

Abstract

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.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Acids / chemistry
  • Catalysis
  • Heterocyclic Compounds / chemical synthesis*
  • Heterocyclic Compounds / chemistry
  • Humans
  • Ionic Liquids / chemistry*
  • MCF-7 Cells
  • Mitochondria / chemistry*
  • Molecular Structure
  • Nitrogen / chemistry*
  • Pyridines / chemical synthesis*
  • Pyridines / chemistry
  • Staining and Labeling*

Substances

  • Acids
  • Heterocyclic Compounds
  • Ionic Liquids
  • Pyridines
  • Nitrogen