Fused pyrazino[2,3-b]indolizine and indolizino[2,3-b]quinoxaline derivatives; synthesis, structures, and properties

Witold M. Bloch, Stephanie M. Derwent-Smith, Fatiah Issa, Jonathan C. Morris, Louis M. Rendina, Christopher J. Sumby

Research output: Contribution to journalArticlepeer-review

27 Citations (Scopus)


The synthesis of six new compounds incorporating either a pyrazino[2,3-b]indolizine or indolizino[2,3-b]quinoxaline core are reported in good yield (58-87%). The intermediates for the key cyclization reaction for one set of compounds (5a-c), with a sterically demanding 3,5-dimethylpyrazole group in the 5-position of the core, were found to be mono-substituted. These intermediates could be isolated and cyclized by heating under acid-catalyzed conditions. To further demonstrate the versatility of the chemistry, compounds 6a-c were synthesized in 58-68% yields. Compounds 5a-c are non-planar in solution and the solid-state, while 6a-c have close to planar conformations, pointing to weak hydrogen bonds between the acidic C-Hs and the adjacent azine nitrogen atoms. The cytotoxicity of the six newly synthesized and three previously prepared compounds was assessed against a human glioblastoma multiforme cell line.

Original languageEnglish
Pages (from-to)9368-9375
Number of pages8
Issue number48
Publication statusPublished - 2 Dec 2011
Externally publishedYes


  • Biological activity
  • Fused heterocycles
  • Organic dyes
  • Synthesis
  • X-ray crystallography


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