Ferrocenyl pyrazolines: Preparation, structure, redox properties and DFT study on regioselective ring-closure

Virág Zsoldos-Mády, Oliver Ozohanics, Antal Csámpai, Veronika Kudar, Dávid Frigyes, Pál Sohár

Research output: Contribution to journalArticle

18 Citations (Scopus)

Abstract

Cyclocondensation of 1-phenyl-3-ferrocenyl-2-propen-1-one (1) with RNHNH2 hydrazines and the substituent-dependent product distribution were investigated. With methylhydrazine, formation of two regioisomeric pairs of pyrazolines and pyrazoles was observed. The ratio of the products varied with the solvent and temperature. Transformation of 5-ferrocenyl-N-substituted pyrazolines into pyrazoles was systematically studied and DDQ was found to be the most suitable reagent. Mechanism of the cyclization reactions taking place under kinetic- and thermodynamic controls was supported with DFT calculations. The energy-dependence of the transformation of pyrazoline to pyrazole was investigated also by EI MS. Structure determination of the new compounds was performed by IR, MS and NMR methods including 2D-HMQC, 2D-HMBC, DEPT and DIFFNOE measurements. For two compounds structures were also proved by X-ray diffraction.

Original languageEnglish
Pages (from-to)4185-4195
Number of pages11
JournalJournal of Organometallic Chemistry
Volume694
Issue number26
DOIs
Publication statusPublished - Dec 15 2009

Keywords

  • DFT calculation
  • Ferrocenes
  • MS and IR study
  • NMR
  • Pyrazoles
  • X-ray

ASJC Scopus subject areas

  • Biochemistry
  • Physical and Theoretical Chemistry
  • Organic Chemistry
  • Inorganic Chemistry
  • Materials Chemistry

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