ChemInform Abstract: Study of Substituted Formylchromones

Substituted derivatives of 2- and 3-formylchromone were synthesized and studied by IR, 13 C and 1 H 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 13 C chemical shifts. Substituents bonded to the aromatic nucleus have only small effect on the electron structure of the pyrone ring.