A new kinetic model for the acid-catalysed reactions of N-(2-aminophenyl)phthalamic acid in aqueous media

(Note: The full text of this document is currently only available in the PDF Version )

Christopher J. Perry


Abstract

The acid-catalysed breakdown of N-(2-aminophenyl)phthalamic acid has been studied in dilute aqueous acids in the pH range 0–6. The dominant reaction is the formation of N-(2-aminophenyl)phthalimide (between ∼80 and ∼100% yields in the pH range studied) and its subsequent rearrangement to 2-(2-carboxyphenyl)benzimidazole, occurring as consecutive pseudo-first-order processes. Anomalously, only a minor hydrolysis reaction is observed.A kinetic model for these processes has been constructed and rate constants and activation parameters evaluated. Mechanisms involving pre-equilibria to form the kinetically significant species have been proposed for the consecutive processes. The approach has been adapted to account for the observed kinetics of acid catalysed formation of benzimidazoles from o-aminoanilides.


References

  1. J. Arient, Russ. Chem. Rev. (Engl. Transl.), 1965, 34, 836 Search PubMed.
  2. P. R. Young, J. Heterocycl. Chem., 1972, 9, 371 CAS.
  3. V. V. Korshak, A. L. Rusanov and R. D. Katsarava, Vysokomol. Soedin., Ser. A, 1972, 14, 1917 Search PubMed.
  4. V. K. Shchel'tsyn, M. I. Vinnick, E. A. Sycheva and G. S. Krasil'nikova, Kinet. Catal. (Engl. Transl.), 1990, 31, 970 Search PubMed.
  5. V. K. Shchel'tsyn, M. I. Vinnick, E. A. Sycheva and G. S. Krasil'nikova, Kinet. Catal. (Engl. Transl.), 1989, 30, 914 Search PubMed.
  6. D. Hawkins, J. Chem. Soc., Perkin Trans. 2, 1976, 642 RSC.
  7. E. Hoffmann and H. Schiff-Shenav, J. Org. Chem., 1962, 27, 4686 CAS.
  8. J. Brown, S. C. K. Su and J. A. Shafer, J. Am. Chem. Soc., 1966, 88, 4468 CrossRef.
  9. K. J. Morgan and A. M. Turner, Tetrahedron, 1969, 25, 915 CrossRef CAS.
  10. J. Arient and J. Marhan, Collect. Czech. Chem. Commun., 1961, 26, 98 CAS.
  11. See for example: C. A. Reynolds, Principles of Analytical Chemistry, Allyn and Bacon, 1966, pp. 60–61 Search PubMed.
  12. H. Morawetz and J. A. Shafer, J. Am. Chem. Soc., 1962, 84, 3783 CrossRef CAS.
  13. C. L. Sharma, R. S. Arya, S. S. Narvi and V. Mishra, J. Indian. Chem. Soc., 1984, 61, 677 Search PubMed.
  14. S. Kahlon, B.Sc. Project Report, University of Wolverhampton, 1994.
  15. M. Gul, B.Sc. Project Report, University of Wolverhampton, 1994.
  16. M. L. Bender, Y.-L. Chow and F. Chloupek, J. Am. Chem. Soc., 1958, 80, 5380 CrossRef CAS.
  17. Organic Chemistry Data Book(S246DB), The Open University, 1991, p. 7 Search PubMed.
  18. C. J. Giffney and C. J. O'Connor, J. Chem. Soc., Perkin Trans. 2, 1975, 706 RSC.
  19. J. G. Colson, R. H. Michel and R. M. Paufler, J. Polym. Sci., Polym. Chem. Ed., 1966, 4, 59 CAS.
  20. P. N. Preston, The Chemistry of Heterocyclic Compounds, Part 1, Wiley-Interscience, 1981, vol. 40, p. 239 Search PubMed.
  21. Handbook of Chemistry and Physics, eds. C. D. Hodgman, R. C. Weast and S. M. Selby, Chemical Rubber Publishing Company, Cleveland, OH, 39th edn, 1957, p. 1615 Search PubMed.