Structural Chemistry

, Volume 8, Issue 3, pp 189–195 | Cite as

Tautomerism and the Mills-Nixon-like effect in pyrazoles

Article

Abstract

Theoretical calculations on a wide variety of NH-pyrazoles clearly show a relationship between ring strain and annular tautomerism, i.e., the most stable tautomer is that having the largest singleond character in the C3-C4 bond.

Key words

Mills-Nixon-like effect AM1 calculations ab initio calculations annular tautomerism NH-pyrazoles 

Preview

Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.

References

  1. 1.
    Mills, W. H.; Nixon, I. G.J. Chem. Soc. 1930, 2510–2524.Google Scholar
  2. 2.
    Mó, 0.; Yáñez, M.; Eckert-Maksic, M.; Maksik, Z. B.J. Org. Chem. 1995,60, 1638–1646, and references therein.Google Scholar
  3. 3.
    Rouhi, A. M.Chem. Eng. News 1996,April 1, 27–31.Google Scholar
  4. 4.
    Laszlo, P.Chem. Intelligencer 1996,2, 37–41.Google Scholar
  5. 5.
    Siegel, J. S.Angew. Chem. Int. Ed. Engl. 1994,33, 1721–1723.Google Scholar
  6. 6. (a)
    Martínez, A.; Jimeno, M. L.; Elguero, J.; Fruchier, A.New J. Chem. 1994,18, 269–277.Google Scholar
  7. 6. (b)
    See also Castro, A.; Martínez, A.J. Chem. Soc. Perkin Trans. 2 1994, 1561.Google Scholar
  8. 7.
    Baldridge, K. K.; Siegel, J. S.J. Am. Chem. Soc. 1992,114, 9583–9587.Google Scholar
  9. 8.
    Eckert-Maksic, M.; Maksic, Z. B.; Klessinger, M.J. Chem. Soc. Perkin Trans. 2 1994, 285–289.Google Scholar
  10. 9.
    Bürgi, H.-B.; Baldridge, K. K.; Hardcastle, K.; Frank, N. L.; Gantzel, P.; Siegel, J. S.; Ziller, J.Angew. Chem. Int. Ed. Engl. 1995,34, 1454–1456.Google Scholar
  11. 10.
    Foces-Foces, C.; Hager, O.; Jagerovic, N.; Jimeno, M. L.; Elguero, J.Chem. Eur. J. 1997,3, 121–126.Google Scholar
  12. 11.
    Llamas-Saiz, A. L.; Foces-Foces, I.; Sobrados, I.; Elguero, J.; Meutermans, W.Acta Crystallogr. C 1993,49, 724–729.Google Scholar
  13. 12.
    Balaban, A. T.; Banciu, M.; Ciorba, V.Annulenes, Benzo-Hetero-, Homo-Derivatives and their Valence Isomers, CRC Press: Boca Raton, Florida,1987, Vol. II, p. 148.Google Scholar
  14. 13.
    Abboud, J.-L. M.; Foces-Foces, C.; Herreros, M.; Homan, H.; Infantes, L.; Notario, R.; Krebs, A. W.; Neubauer, J.; Elguero, J.; Jagerovic, N.J. Phys. Org. Chem. 1996,9, 79–86.Google Scholar
  15. 14.
    Forfar, I.; Cabildo, P.; Claramunt, R. M.; Elguero, J.Chem. Lett. 1994, 2079–2080.Google Scholar
  16. 15.
    Aguilar-Parrilla, F.; Minguet-Bonvehí, M.; Klein, O.; Limbach, H.-H.; Claramunt, R. M.; Santa María, M. D.; Forfar, I.; Elguero, J.J. Chem. Soc. Perkin Trans. 2, in press.Google Scholar
  17. 16.
    Catalán, J.; de Paz, J. L. G.; Elguero, J.J. Chem. Soc. Perkin Trans. 2 1996, 57–60.Google Scholar
  18. 17. (a)
    Stanger, A.; Vollhardt, P. C.J. Org. Chem. 1988,53, 4890–4892.Google Scholar
  19. 17. (b)
    Stanger, A.J. Am. Chem. Soc. 1991,113, 8277–8280.Google Scholar
  20. 18.
    Gilli, G.; Bellucci, F.; Ferretti, V.; Bertolasi, V.J. Am. Chem. soc. 1989,111, 1023–1028.Google Scholar
  21. 19.
    Hibbert, F.; Emsley, J.Adv. Phys. Org. Chem. 1990,26, 255–379.Google Scholar
  22. 20. (a)
    Garbisch, E. W.J. Am. Chem. Soc. 1963,85, 1696–1697.Google Scholar
  23. 20. (b)
    Garbisch, E. W.J. Am. Chem. Soc. 1965,87, 505–510.Google Scholar
  24. 20. (c)
    Bolvig, S.; Hansen, P. E.Magn. Res. Chem. 1996,34, 467–478.Google Scholar
  25. 21.
    Ramos, M.; Alkorta, I.; Elguero, J.Tetrahedron. 1997,53, 1403–1410.Google Scholar
  26. 22.
    Dewar, M. J. S.; Zoebisch, E. G.; Heafely, E. F.; Stewart, J. J. P.J. Am. Chem. Soc. 1985,107, 3902–3909.Google Scholar
  27. 23.
    Stewart, J. J. P. Mopac 6.0, QCPE program 455.Google Scholar
  28. 24.
    Frisch, M. J.;et al. Gaussian 94, Revision B.3. Pittsburgh, Pennsylvania: Gaussian, Inc., 1995.Google Scholar
  29. 25.
    Hariharan, P. C.; Pople, J. A.Theor. Chim. Acta 1973,28, 213–222.Google Scholar

Copyright information

© Plenum Publishing Corporation 1997

Authors and Affiliations

  1. 1.CSICInstituto de Química MédicaMadridSpain

Personalised recommendations