Monatshefte für Chemie / Chemical Monthly

, Volume 112, Issue 11, pp 1325–1332 | Cite as

Beiträge zur Chemie der Pyrrolpigmente, 42. Mitt. Kraftfeldrechnungen an Gallenfarbstoffen: Die Energiehyperfläche rubinoider Pigmente

  • Heinz Falk
  • Norbert Müller
Organic Chemistry and Biochemistry

On the chemistry of pyrrole pigments, XLII: Force field calculations on bile pigments: The energy hypersurface of rubinoid pigments

Abstract

The energy hypersurface of rubinoid bile pigments is calculated using a force field model previously described. Two cases are observed. I: The pigment is substituted symmetrically or unsymmetrically by apolar groups. This results in a very shallow energy valley containing several enantiomeric conformers of approximately equal energies. II: Substitution by polar groups, especially in position 8 and 12 of the rubin skeleton, (e.g.−CH2−CH2−COOH) is followed by a “lock in” bonding between such groups and the lactam ring functions. Thereby only two enantiomeric conformers, which are energetically stabilized, are possible. The barrier between these species amounts to about 40 kJ/mol. These results are compared with the experimental facts available so far. An analysis of the corresponding energy hypersurfaces of the diastereomeric forms of (Z,Z)-, (E,Z)-, (Z,E)- and (E,E)-configurations is given as well.

Keywords

Bilirubin Conformational analysis Force field calculations 

Preview

Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.

Literatur

  1. 2.
    Falk H., Höllbacher G., Hofer O., Müller N., Mh. Chem.112, 391 (1981).Google Scholar
  2. 3.
    Falk H., Grubmayr K., Thirring K., Gurker, N., Mh. Chem.109, 1183 (1978).Google Scholar
  3. 4.
    Falk H., Gergely S., Grubmayr K., Hofer O., Ann. Chem.1977, 565.Google Scholar
  4. 5.
    Gust D., Mislow K., J. Amer. Chem. Soc.95, 1535 (1973).Google Scholar
  5. 6.
    Favini G., Pitea, D., Manitto K., Nouv. J. Chim.3, 299 (1979).Google Scholar
  6. 7.
    Siehe IUPAC Commission on Nomenclature of Organic Chemistry: Pure Appl. Chem.45, 13 (1976) und die vorangegangenen Mitt.Google Scholar
  7. 8.
    Siehe z. B.:Dale J.: Stereochemie und Konformationsanalyse. Weinheim: Verlag Chemie. 1978.Google Scholar
  8. 9.
    Bonnett R., Davies J. E., Hursthouse M. B., Nature262, 326 (1976).Google Scholar
  9. 10.
    Le Bas G., Allegret A., Manguen Y., De Rango C., Bailly M., Acta Cryst. B36, 3007 (1980).Google Scholar
  10. 11.
    Mugnoli A., Manitto P., Monti D., Nature273, 568 (1978).Google Scholar
  11. 12.
    Sheldrick W. S., Becker W., Z. Naturforsch.34 b, 1542 (1979).Google Scholar
  12. 13.
    Manitto P., Monti D., Chem. Commun.1976, 122.Google Scholar

Copyright information

© Springer-Verlag 1981

Authors and Affiliations

  • Heinz Falk
    • 1
  • Norbert Müller
    • 1
  1. 1.Institut für Analytische, Organische und Physikalische ChemieJohannes-Kepler-Universität LinzLinzÖsterreich

Personalised recommendations