Study of Substituted Formylchromones

Abstract

Substituted derivatives of 2- and 3-formylchromone were synthesized and studied by IR, 13C and 1H NMR spectroscopy and the AM1 quantum chemical method. Energy and electron distribution calculations confirm the preference of the synplanar conformation in 3-formylchromones. The calculated charges on the carbon atoms correlate well with the experimental 13C chemical shifts. Substituents bonded to the aromatic nucleus have only small effect on the electron structure of the pyrone ring.