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Chemistry of Natural Compounds

, Volume 11, Issue 5, pp 613–616 | Cite as

Ultraviolet absorption of flavonoids. V. The structure of 3- and 5-hydroxyflavones

  • N. A. Tyukavkina
  • N. N. Pogodaeva
  • E. I. Brodskaya
  • Yu. M. Sapozhnikov
Article

Summary

1. The peculiarities of the properties of 3-hydroxyflavone are due to the fact that the introduction of the proton-donating hydroxy group directly into the heterocycle leads to an increase in the aromaticity of the pyrone fragment through the stabilization of a pyrylium structure.

2. The causes of the decreased acidity and basicity of 5-hydroxyflavone are the formation of an intramolecular hydrogen bond of the chelate type and a disturbance of the coplanarity of the molecule. The combination of these factors explains the anomalously high position of the band of the stretching vibrations of the carbonyl group of this compound.

Keywords

Carbonyl Group Flavone Hydroxy Group Intramolecular Hydrogen Bond Methyl Ether 

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Copyright information

© Plenum Publishing Corporation 1976

Authors and Affiliations

  • N. A. Tyukavkina
  • N. N. Pogodaeva
  • E. I. Brodskaya
  • Yu. M. Sapozhnikov

There are no affiliations available

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