A facile access to new diazepines derivatives: Spectral characterization and crystal structures of 7-(thiophene-2-yl)-5-(trifluoromethyl)-2,3-dihydro-1H-1,4-diazepine and 2-thiophene-4-trifluoromethyl-1,5-benzodiazepine

Guillermo Ahumada, David Carrillo, Carolina Manzur, MAURICIO DANIEL FUENTEALBA CARRASCO, Thierry Roisnel, Jean René Hamon

Research output: Contribution to journalArticlepeer-review

8 Scopus citations

Abstract

The one-pot double condensation reaction of 2-thenoyltrifluoroacetone (2-TTA) with ethylendiamine or o-phenylenediamine, in a 2:1 stoichiometric molar ratio, leads to the formation of 7-(thiophene-2-yl)-5-(trifluoromethyl)-2,3-dihydro-1H-1,4-diazepine 2 and 2-thiophene-4-trifluoromethyl-1,5-benzodiazepine 3, that were isolated in 56 and 53% yields, respectively. The bis(trifluoroacetamide)ethylene derivative 1 was also isolated in 32% yield as a side-product in the reaction of 2-TTA and ethylenediamine. Compounds 1–3 were fully characterized by elemental analysis, FT-IR and multinuclear (1H, 13C and 19F) NMR spectroscopy. In addition, their molecular identities and geometries have been authenticated by single-crystal X-ray diffraction analysis. The spectroscopic and structural data confirm that the 1,4-diazepine 2 and the 1,5-benzodiazepine 3 exist in the imine-enamine and diimine tautomeric forms, respectively, both in solution and in the solid-state.

Original languageEnglish
Pages (from-to)781-787
Number of pages7
JournalJournal of Molecular Structure
Volume1125
DOIs
StatePublished - 5 Dec 2016

Keywords

  • 2-Thenoyltrifluoroacetone
  • Benzodiazepine
  • Diazepine
  • Imine-enamine tautomerism
  • Single-crystal X-ray diffraction
  • Trifluoroacethyl-derivatives

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