Abstract
The polybutoxytitanates catalysis of aniline acylation by orthosubstituted benzoic acids leads to the production of substituted benzanilides. Catalytic rate constants of the second order reaction (the first with respect to aniline and ortho-substituted benzoic acid; boiling ortho=xylene, 145°C) correlate well according to the Hammett and Bronsted equations with straight line segments with ρ=1.93 and α=0.66, in contrast to the reaction of aniline with meta- and parasubstituted benzoic acids and substituted anilines with benzoic acid. This dependence drops out 2=nitrobenzoic and 1=naphthoic acids, which have relatively low reactivity and the greatest steric hindrances both for nucleophilic attack by aniline and for possible coordination with catalytically active centers of the corresponding ortho-substituted titanium polybutoxybenzoates formed in situ.
Based on these data, the previously proposed mechanism of bifunctional catalysis due to titanium polybutoxybenzoates and their complexes with meta- and parasubstitutedbenzanilides was supplemented by the possibility of the steric inhibition of reaction by the most bulky substituents and chelate structures formation of orthosubstituted benzoic acids and their anilides with individual titanium atoms of the catalyst, as well as the simultaneous H-bonding of the amino group hydrogen atoms of aniline, which leads to its activation to a nucleophilic attack, with a carbonyl group and an orthopositioned substituent of the orthobenzoate ligand in the coordination sphere of titanium. Taking into account such chelation and steric barriers, as well as inhibition of acid catalysis due to the formation of the imide form of anilides, containing electron-withdrawing substituents, the equations for the rate constants of the catalytic reaction of ortho-substituted benzoic acids with aniline are derived, corresponding to the experimentally obtained Hammett dependence.
References
Leggio А., Bagalа J., Belsito E.L., Comandu A., Greco M., Liguori A. Formation of amides: one pot condensation of carboxylic acids and amines mediated by TiCl4. Chem. Cent. J. 2017. 11(1): 87.
Lundberg Н. Group (IV) metal-catalyzed direct amidation. Synthesis and mechanistic considerations. Stockholm University, Department of Organic Chemistry. 2015.
ShteinbergL.Ya., Коndratov S.А.,Shein S.M. Metallocomplex catalysis in the acylation of aniline by substituted benzoic acids. Zhurn. organ. khimii. 1988. 24(9): 1968.
Коndratov S.А.,ShteinbergL.Ya., Shein S.M. Catalytic synthesis of anilide of 2,3=hydroxynaphthoic acid. Ibid. 1993. 29(9): 1914.
ShteinbergL.Ya. The effect of substituents on the reaction rate of substituted anilines with benzoic acid, catalyzed by polybutoxytitanates. Ukr. khim. zhurn. 2020. 86(1): 3.
ShteinbergL.Ya. The effect of substituents on the reaction rate of meta- and parasubstituted benzoic acids with aniline, catalyzed by polybutoxytitanates. Ibid. 2020. 86(6): 3.
ShteinbergL.Ya. Catalysis in the acylation of arylamines by aromatic carboxylic acids. Dis. cand. chemical sciences. Moscow.1988.
Davis M.M., Hetze H.B. Relative strengths of forty aromatic carboxylic acids in benzene at 25⁰C.J. Res. National Bureau of Standards. 1958. 60(6): 569.
Аlbert А., Serjeаnt Е.Acid and base ionization constants. (M. – L.: Khimiya, 1964). [in Russian].
ShteinbergL.Ya. The effect of the addition of substituted benzanilides on the rate of the reaction of aniline with benzoic acid, catalyzed bytetrabutoxy titanium and polybutoxytitanates. Ukr. khim. zhurn. 2019. 85(1): 19.
Pat. US 3098095. Process for resolving aromatic polycarboxylic acids capable of forming intramolecular anhydrides //Knobloch J.O., Shepard J.W., Liao H.P. 1963.
Sаdovnikov А.I. Regularities of amide formation with the participation of carboxylic acid anhydrides and aromatic amines. Izv. vuzov. Khimiyaikhim. tеshnologiya. 2007. 50(5): 3.
Panchenkov G.M., Lebedev V.P. Chemical kinetics and catalysis. Training for universities. (Мoscow: Chimiya, 1985). [in Russian].
Zhdanov Yu.А., Minkin V.I. Correlation analysis in organic chemistry. (Rostov: Publishing house of Rostov University, 1966). [in Russian].
Pаlm V.А.Fundamentals of the quantitative theory of organic reactions. (Leningrad: Chimiya, 1977). [in Russian].
Davis М.М. Acid-base behavior in aprotic organic solvents. National Bureau of standards. Washington. 1968.
LeggeG.M.Sс. Kinetics and mechanism of the esterification of carboxylic acids catalysed by titanium compounds. Dis. Dr. of philоsophy. the University of Нull. 1980.
Gandhi V.G., Mishra M.K., Rao M.S., Kumar A., Joshi P.A., Shah D.O. Comparative study on nano-crystalline titanium dioxide catalyzed photocatalytic degradation of aromatic carboxylic acids in aqueous medium. J. Industrial and Engineering Chemistry. 2011. 17(2): 331.
Bender M., Bergeron R., Коmiyama M. Bioorganic chemistry of enzymatic catalysis. (М.: Мir, 1987). [in Russian].
Hong K., Bak W., Chun H. Robust molecular сrystals of titanium(IV)-oxo-carboxylate clusters showing water stability and CO2 sorption capability. Inorg. Chem. 2014. 53(14): 7288.
Li N., Matthews P.D., Luob H.-K., Wright D.S. Novel properties and potential applications of functional ligand-modified polyoxotitanate cages. Chem. Commun. 2016. 52: 11180.
Sen Gupta S.K., Mishra S., Rani V.R., Arvind U. General acid catalysis in benzoic acid–crystal violet carbinol base reactions in toluene. International J. of Chemical Kinetics. 2012. 8: 570.
DOI 10.1002/kin.20628.
Hansch C., Leo A. Substituent constants for correlation analysis in chemistry and biology. – New York: Wiley-Interscience, 1979.
Science of synthesis: Houben-Weyl. Methods of molecular transformations. 2007. 31a.
Böhm S., Fiedler P., Exner O. Analysis of the ortho effect: acidity of 2=substituted benzoic acids. New J. of Chemistry. 2004. 28: 67.
https://pubs.rsc.org/en/content/articlehtml/2004/nj/b305986c
Shmid R., Sapunov V.N. Non-formal kinetics. In search of ways of chemical reactions. Мoscow: Mir, 1985. [in Russian].
Iman A., Zahia Z. Theoretical study of some structures of titanium (IV) complexes derived from 2=, 3= and 4=hydroxyl-benzoic acids. Bull. Chem. Soc. Ethiop. 2018. 32(3): 571.
https://dx.doi.org/10.4314/bcse.v32i3.15
Irshaidat T. Modulating the electronic structure of amino acids: interaction of model Lewis acids with anthranilic acid. Quím. Nova. 2014. 37(9): 1446.
ISSN 0100-4042.