Improved solvent-free synthesis and structure elucidation of (E)- and (Z)-4-(arylmethylene)-3-isochromanones

Tamás Lóránd, Péter Forgó, András Földesi, Erzsébet Ôsz, László Prókai

Research output: Contribution to journalArticle

9 Scopus citations

Abstract

A series of new 4-(arylmethylene)-3-isochromanones 1-17 has been prepared by base-catalyzed Knoevenagel condensations. Stereochemical and conformational analyses were performed by 1H and 13C NMR methods, and X-ray crystallography was used to complement the configurational assignment for a representative product. The reaction generally yields the (E) isomer, but the isomeric composition of the products was influenced by the aromatic aldehyde and usually governed by the stability of the products. Several aldehydes exclusively afforded the (Z) isomer, due to intramolecular steric/electronic interactions reflected in the increased stability of the product. The condensation performed with ortho-hydroxyarenecarbaldehydes furnished the unexpected 3-arylcoumarins or 3-arylbenzocoumarins.

Original languageEnglish
Pages (from-to)2996-3003
Number of pages8
JournalEuropean Journal of Organic Chemistry
Issue number17
DOIs
StatePublished - Sep 2002

Keywords

  • Heterocycles
  • Lactones
  • Molecular modeling
  • NMR spectroscopy
  • X-ray diffraction

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