Chemistry of Natural Compounds

, Volume 8, Issue 2, pp 178–180 | Cite as

Ultraviolet absorption of flavonoids III. Ionization constants of the 5-hydroxy group in 5,x-dihydroxyflavones

  • N. A. Tyukavkina
  • N. N. Pogodaeva


The ionization constants of the hydroxy groups in 5-hydroxy-, 3,5- and 4′,5-dihydroxy- and 3-hydroxy-5-methoxyflavones and in 5-hydroxy-7-methoxyflavanone have been determined. It has been shown that because of intramolecular hydrogen bonding the 5-hydroxy group has a reduced acidity. However, the capacity for ionization of the 5-hydroxy group changes under the influence of hydroxy groups introduced into the 3, 4′, or 7 positions, and also on passing to the flavanone series.


Flavone Hydroxy Group Intramolecular Hydrogen Bonding Flavanone Chrysin 


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Literature cited

  1. 1.
    N. A. Tyukavkina and N. N. Pogodaeva, Khim. Prirodn. Soedin., 11 (1971).Google Scholar
  2. 2.
    I. D. Sadekov, V. I. Minkin, and A. E. Lutskii, Usp. Khim.,39, 380 (1970).CrossRefGoogle Scholar
  3. 3.
    T. R. Seshadri, Biochem.,20, 1987 (1951).CrossRefGoogle Scholar
  4. 4.
    T. A. Geissman, J. Amer. Chem. Soc.,64, 1704 (1942).CrossRefGoogle Scholar
  5. 5.
    Yu. A. Zhdanov and V. I. Minkin, Correlation Analysis in Organic Chemistry [in Russian], Rostov (1966).Google Scholar
  6. 6.
    N. A. Tyukavkina, N. N. Pogodaeva, and V. I. Lutskii, Khim. Prirodn. Soedin., 24 (1970).Google Scholar
  7. 7.
    L. J. Porter and K. R. Markham, J. Chem. Soc.,1970, 344.Google Scholar
  8. 8.
    S. Sugasawa, J. Chem. Soc.,1934, 1483.Google Scholar
  9. 9.
    J. H. Looker and W. Hanneman, J. Heterocycl. Chem.,3, 55 (1966).CrossRefGoogle Scholar
  10. 10.
    T. R. Seshadri and V. Venkateswarlu, Proc. Indian Acad. Sci.,23A, 191 (1947).Google Scholar
  11. 11.
    I. Z. Syed and T. S. Wheeler, J. Chem. Soc.,1936, 1714.Google Scholar
  12. 12.
    P. Moses and R. Dahlbom, Acta Chem. Scand.,24, 312 (1970).CrossRefGoogle Scholar
  13. 13.
    V. I. Lutskii, N. A. Tyukavkina, and M. F. Shostakovskii, Khim. Prirodn. Soedin., 383 (1968).Google Scholar
  14. 14.
    A. Albert and E. Serjeant, Ionization Constants of Acids and Bases, Methuen London (1962).Google Scholar
  15. 15.
    N. P. Komar', Tr. In-ta Khimii KhGU,8, 57 (1951).Google Scholar
  16. 16.
    K. Doerfel, “Beurteilung von Analysenverfahren und -ergibnissen,” Z. Anal. Chem.,185, 1–98 (1962).CrossRefGoogle Scholar

Copyright information

© Consultants Bureau 1974

Authors and Affiliations

  • N. A. Tyukavkina
  • N. N. Pogodaeva

There are no affiliations available

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