Chemistry of Heterocyclic Compounds

, Volume 15, Issue 3, pp 322–327 | Cite as

Electronic interactions in aromatic an heteroaromatic two-ring systems

3. IR and PMR spectra of methyl derivatives
  • N. N. Zatsepina
  • I. F. Tupitsyn
  • A. I. Belyashova
  • N. S. Kolodina
  • A. A. Kane
  • G. N. Sudakova
Article
  • 41 Downloads

Abstract

The chemical shifts of the methyl protons (\(\delta ^{CH_3 }\)) in the PMR spectra and the integral intensities (A1/2) of the band of the symmetrical CH stretching vibration of the methyl group in the IR spectra were measured for an extensive series of methyl derivatives of aromatic and heteroaromatic compounds including 3-, 4-, 5-, and 6-substituted 1- and 2-methylnaphthalenes, 4-, 5-, 6-, and 7-substituted 2-methylquinolines, and 5- and 6-substituted 2-methylbenzothiazoles, as well as a number of two- and three-ring systems that do not contain substituents. The changes in the chemical shifts are interpreted with allowance for two principal contributions: the contribution from the ring currents and the contribution from the changes in the electron densities (q) on the H and C atoms of the methyl group. The fact of the existence of a linear relationship between the corrected (for the ring current) \(\delta ^{CH_3 }\) values and the calculated (by the CNDO/2 method) electron charges qC and qH (the latter plays the dominant role) indicates that the electronic effects of the substituent make the principal contribution to the changes in the shielding constants of the protons of the methyl group in most of the investigated compounds. Similarly, the charges on the H and C atoms of the methyl group convey the trend of the integral intensities of the IR bands, thereby confirming the primarily electronic nature of the effects of structural factors on the A1/2 values.

Keywords

Chemical Shift Electron Charge Integral Intensity Methyl Proton Electronic Effect 

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Literature cited

  1. 1.
    N. N. Zatsepina, I. F. Tupitsyn, V. P. Dushina, Yu. M. Kapustin, and Yu. L. Kaminskii, Reakts. Sposobnost' Org. Soedin., 9, 745 (1972).Google Scholar
  2. 2.
    N. N. Zatsepina, A. A. Kane, N. S. Kolodina, and I. F. Tupitsyn, Reakts. Sposobnost' Org. Soedin., 10, 353 (1973).Google Scholar
  3. 3.
    N. N. Zatsepina, I. F. Tupitsyn, A. I. Belyashova, A. A. Kane, N. S. Kolodina, and G. N. Sudakova, Khim. Geterotsikl. Soedin., No. 8, 1110 (1977).Google Scholar
  4. 4.
    J. A. Pople and M. J. Gordon, J. Amer. Chem. Soc., 89, 4253 (1967).Google Scholar
  5. 5.
    D. A. Dawson, G. K. Hamer, and W. F. Reynolds, Can. J. Chem., 52, 39 (1974).Google Scholar
  6. 6.
    O. Kajimoto and T. Fueno, Chem. Lett., No. 1, 103 (1972).Google Scholar
  7. 7.
    J. Niwa, Bull. Chem. Soc. Japan, 48, 118 (1975).Google Scholar
  8. 8.
    H. Sterk and H. Holzer, Org. Magn. Reson., 6, 133 (1974).Google Scholar
  9. 9.
    G. Barbeeri, R. Benassi, P. Lazzeretti, L. Schenetti, and F. Taddei, Org. Magn. Reson., 7, 451 (1975).Google Scholar
  10. 10.
    J. Niwa, Bull. Chem. Soc. Japan, 50, 959 (1977).Google Scholar
  11. 11.
    A. R. Katritzky and Y. Takeuchi, Org. Magn. Reson., 2, 569 (1970).Google Scholar
  12. 12.
    G. D. Modica, E. Barni, and A. Gasco, J. Heterocycl. Chem., 2, 457 (1965).Google Scholar
  13. 13.
    R. J. Quellette and B. G. Leuven, J. Org. Chem., 34, 62 (1969).Google Scholar
  14. 14.
    P. J. Black, R. D. Brown, and M. L. Heffernan, Austral. J. Chem., 20, 1305, 1325 (1967).Google Scholar
  15. 15.
    G. Hall, A. Harlisson, and L. M. Jackman, Disc. Faraday Soc., 34, 15 (1962).Google Scholar
  16. 16.
    W. Adam, A. Grimson, and C. Rodrigues, Tetrahedron, 23, 2513 (1967).Google Scholar
  17. 17.
    G. Galli and J. Fruwert, Z. Chem., 16, 57 (1976).Google Scholar

Copyright information

© Plenum Publishing Corporation 1979

Authors and Affiliations

  • N. N. Zatsepina
    • 1
  • I. F. Tupitsyn
    • 1
  • A. I. Belyashova
    • 1
  • N. S. Kolodina
    • 1
  • A. A. Kane
    • 1
  • G. N. Sudakova
    • 1
  1. 1.State Institute of Applied ChemistryLeningrad

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