View PDF Version
 
DOI: 10.1039/A805854G (Paper) Reference Section for: J. Chem. Soc., Perkin Trans. 2, 1998, 2207-2210

The acid-catalysed decomposition of N-nitrotolazoline

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

Jim Iley, Fatima Norberto and Paula Sardinha

Abstract

Reaction of tolazoline with N2O4 yields N-nitrotolazoline, the prototypical nitroamidine. N-Nitrotolazoline undergoes acid-catalysed hydrolysis of the nitroamidine function to form N-(2-hydroxyethyl)phenylacetamide. The observed pseudo-first-order rate constants, k0, have a non-linear dependence upon acidity, displaying saturation at higher acid concentrations consistent with a mechanism involving equilibrium protonation of N-nitrotolazoline prior to subsequent decomposition of the protonated intermediate. Reactions are subject neither to general acid- or base-catalysis nor to catalysis by thiocyanate ion. The solvent deuterium isotope effect for protonation was found to be 0.3, and for decomposition of the protonated intermediate, 1.7. A value of (–100 ± 5) J K–1 mol–1 was determined for ΔS[hair space] ‡ for the decomposition step. Thus, hydrolysis of the protonated intermediate involves rapid attack of a molecule of water at the amidine carbon atom followed by a slow, intramolecular rearrangement involving proton transfer.

References

  1. J. R. Leis, J. A. Moreira, F. Norberto, J. Iley and L. García-Rio, J. Chem. Soc., Perkin Trans. 2, 1998, 655 RSC.
  2. J. R. Leis, F. Norberto, J. A. Moreira and J. Iley, J. Chem. Res. (S), 1997, 88 RSC.
  3. F. Norberto, J. A. Moreira, E. Rosa, J. Iley, J. R. Leis and E. Peña, J. Chem. Soc., Perkin Trans. 2, 1993, 1561 RSC.
  4. J. Iley, F. Norberto, E. Rosa, V. Cardoso and C. Rocha, J. Chem. Soc., Perkin Trans. 2, 1993, 591 RSC.
  5. J. Iley, F. Norberto and E. Rosa, J. Chem. Soc., Perkin Trans. 2, 1989, 1471 RSC.
  6. E. H. White and W. R. Feldman, J. Am. Chem. Soc., 1957, 79, 5832 CrossRef CAS.
  7. B. Challis, E. Rosa, F. Norberto and J. Iley, J. Chem. Soc., Perkin Trans. 2, 1989, 1823 RSC.
  8. B. Challis, E. Rosa, F. Norberto and J. Iley, J. Chem. Soc., Perkin Trans. 2, 1990, 179 RSC.
  9. Martindale: The Extra Pharmacopoeia, ed. J. E. F. Reynolds, The Royal Pharmaceutical Society, London, 29th edn., 1989 Search PubMed.
  10. W. P. Jencks, J. Regenstein, ‘Ionization constants of acids and bases’, in Handbook of Chemistry and Molecular Biology, ed. G. D. Fasman, CRC Press, Cleveland, OH, 3rd edn., 1976, vol. 1, p. 305 Search PubMed.
  11. T. G. Bonner and J. C. Lockhart, J. Chem. Soc., 1958, 3858 RSC.
  12. D. V. Banthorpe, E. D. Hughes and D. L. H. Williams, J. Chem. Soc., 1964, 5349 RSC.
  13. I. D. Biggs and D. L. H. Williams, J. Chem. Soc., Perkin Trans. 2, 1975, 107 RSC.
  14. N. S. Isaacs, Physical Organic Chemistry, Longman, Harlow, 1987, p. 469 Search PubMed.
  15. T. G. Bonner and J. C. Lockhart, J. Chem. Soc., 1958, 3852 RSC.
  16. C. N. Berry and B. C. Challis, J. Chem. Soc., Perkin Trans. 2, 1974, 1638 RSC.
  17. B. C. Challis and S. P. Jones, J. Chem. Soc., Perkin Trans. 2, 1975, 153 RSC.
Click here to see how this site uses Cookies. View our privacy policy here.