Crystal structures of four 1-(aryl)-[1,2,4]triazolo[4,3-a]quinoxaline derivatives

Thais C. M. Nogueira, Alessandra C. Pinheiro, Marcus V. N. de Souza, Thomas C. Baddeley, James L. Wardell*, Solange M. S. V. Wardell

*Corresponding author for this work

Research output: Contribution to journalArticle

Abstract

The crystal structures of four 1-aryl-[1,2,4]triazolo[4,3-alpha]quinoxaline derivatives, 2, are reported: [aryl = 3-CIC6H4: 2a; 2-HOC6H4:2b;2,3-(HO)(2)C6H3: 2c; and 3,4-(MeO)(2)C6H3: 2d] The compounds, 2, were prepared by oxidation of substituted arenealdehyde quinoxalin-2-ylhydrazones, 1, using ferric chloride in alcohol. In each of the four compounds, the three ring -[1,2,4]triazolo[4,3-alpha]quinoxaline moiety is a near planar moiety, with all ring atoms within 0.1 of the best plane. There are large dihedral angles, 59 +/- 7 degrees, between the [1,2,4]triazolo[4,3-alpha]quinoxaline system and the phenyl ring. The ortho sited hydroxyl groups in 2c are jointly involved in a single O-H center dot center dot center dot O intramolecular hydrogen bond and individually in O-H center dot center dot center dot N intermolecular interactions, while the hydroxyl group in 2b is involved in an intermolecular O-H center dot center dot center dot N hydrogen bond. These and weaker intermolecular interactions, including some of C-H center dot center dot center dot Z (Z = O, N and or pi) and pi center dot center dot center dot pi interactions generate the supramolecular arrangements in 2b and 2c. Intermolecular C-H center dot center dot center dot Z (Z = O, N and or pi) and pi center dot center dot center dot pi interactions are only present in 2a and 2d. (C) 2016 Elsevier B.V. All rights reserved.

Original languageEnglish
Pages (from-to)579-589
Number of pages11
JournalJournal of Molecular Structure
Volume1128
Early online date10 Sep 2016
DOIs
Publication statusPublished - 15 Jan 2017

Keywords

  • [1,2,4]Triazolo[4,3-a]quinoxaline derivatives
  • Ferric chloride oxidation
  • Benzaldehyde quinoxalin-2-ylhydrazones
  • Supramolecular arrangements
  • Hydrogen bonding
  • pi center dot center dot center dot pi interactions
  • ADENOSINE RECEPTOR ANTAGONISTS
  • BIOLOGICAL EVALUATION
  • 4,3-A QUINOXALINES
  • MEDIATED SYNTHESIS
  • METAL-COMPLEXES
  • HYDRAZONES
  • POTENT
  • AGENTS
  • CYCLIZATION
  • ANTICANCER

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