Abstract
The relative position of the equilibria of proton transfer via a hydrogen bond and dissociation of the H complexes to give solvated ions was determined on the basis of a study of the dependence of the chemical shifts and the spin-spin coupling constants of aromatic protons in the PMR spectrum of 4-methyl-7-azaindoline on the acetic and trifluoracetic acid concentrations in methylene chloride. The protolytic equilibrium in the amine-CF3COOH system is shifted completely to favor H complexes of the ion pair type when the reagent ratio is nearly equimolar. A molecular complex ⇄ ion pair equilibrium is observed in the reaction with CH3COOH under the same conditions. The results were confirmed by measurement of the IR spectra of the investigated systems. The enthalpy (-ΔH = 2.9 ± 0.7 kcal/mole) and entropy (-ΔS = 8.0 ± 2 kcal/mole·deg) of proton transfer via a hydrogen bond were determined from the PMR spectra measured at +25° to −50°.
This is a preview of subscription content, log in via an institution to check access.
Similar content being viewed by others
Literature cited
I. V. Komissarov, Elements of the Theory of Receptors in Molecular Pharmacology [in Russian], Moscow (1969), pp. 147 and 169.
A. Albert, Selective Toxicity. The Physico-Chemical Basis of Therapy, Halsted Press New York (1973).
L. Sobczyk and Z. Pawelka., Rocz. Chem., 47, 1523 (1973).
G. V. Gusakova, G. S. Denisov, and A. L. Smolyanskii, Zh. Prirodn. Soedin., 16, 320, 503 (1972).
L. I. Derevyanko and M. N. Tsarevskaya, Zh. Obshch. Khim., 42, 36 (1972).
G. G. Dvoryantseva, T. N. Ul'yanova, Yu. N. Sheinker, and L. N. Yakhontov, Khim. Geterotsikl. Soedin., 767 (1973).
P. Shuster, Z. Chem., 13, 41 (1973).
R. E. Willette, Advances in Heterocyclic Chemistry, 9, 27 (1968).
E. Spinner, J. Chem. Soc., 3119 (1962).
G. V. Gusakova, G. S. Denisov, A. L. Smolyanskii, and V. M. Shraiber, Dokl. Akad Nauk SSSR, 193, 1065 (1970).
L. N. Yakhontov, M. Ya. Uritskaya, and M. Ya. Rubtsov, Zh. Obshch. Khim., 34, 1449 (1964).
A. Hammett, Physical Organic Chemistry, McGraw-Hill, New York (1940).
Author information
Authors and Affiliations
Additional information
Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 1, pp. 76–82, January, 1976.
Rights and permissions
About this article
Cite this article
Dvoryantseva, G.G., Ul'yanova, T.N., Sheinker, Y.N. et al. Investigation of the reaction of 4-methyl-7-azaindoline with acetic and trifluoroacetic acids in methylene chloride by PMR and IR spectroscopy. Chem Heterocycl Compd 12, 70–76 (1976). https://doi.org/10.1007/BF00473917
Received:
Issue Date:
DOI: https://doi.org/10.1007/BF00473917