Mechanism of the dimethyldioxirane oxidation of N,N-dimethylanilines

Abstract

Relative rates of dimethyldioxirane oxidation of a number of para-substituted N,N-dimethylanilines in acetone at 5 °C are compared with those of reactions with methyl iodide and other oxidants. The reactions with dimethyldioxirane followed the Hammett relationship with a ρ value of –1.0. Measurement of the second order rate constants for the dimethyldioxirane reactions in aqueous acetonitrile containing potassium nitrate at 21 °C, showed better correlation with the Hammett relationship (ρ = 0.89) than with the Okamoto–Brown model (ρ⁺ = 0.56). The reaction rates are accelerated greatly in the presence of water such that the respective pseudo first order rate constants for the oxidation of N,N-dimethyl-4-nitroaniline in acetone and water are 6.3 × 10^–3 and 5.86 s^–1, respectively. All of the data are consistent with a concerted electrophilic mechanism and there is no evidence of free radical or electron transfer reactions.

References

1. (a) W. Adam and L. Hadjiarapoglou, Top. Curr. Chem., 1993, 164, 45; (b) R. Curci, in Advances in Oxygenated Processes, ed. A. L. Baumstark, JAI Press, Greenwich, 1990, pp. 1–59.
2. R. W. Murray and D. L. Shang, J. Chem. Soc., Perkin Trans. 2, 1990, 349.
3. R. W. Murray, R. Jeyaraman and M. K. Pillay, J. Org. Chem., 1987, 52, 746.
4. R. W. Murray and H. Gu, J. Org. Chem., 1995, 60, 5673.
5. W. Adam and D. Golsch, Angew. Chem., Int. Ed. Eng., 1993, 32, 737.
6. A. L. Baumstark, M. Beeson and P. C. Vasquez, Tetrahedron Lett., 1989, 30, 5567.
7. F. Kovac and A. L. Baumstark, Tetrahedron Lett., 1994, 35, 8751.
8. A. Bravo, F. Fontana, G. Fronza, F. Minisci and A. Serri, Tetrahedron Lett., 1995, 38, 6945.
9. F. Minisci, L. Zhao, F. Fontana and A. Bravo, Tetrahedron Lett., 1995, 36, 1697.
10. J. K. Crandall, M. Zucco, R. S. Kirsch and D. M. Coppert, Tetrahedron Lett., 1991, 32, 5441.
11. A. Altamura, C. Fusco, L. D'Accolti, R. Mello, T. Prencipe and R. Curci, Tetrahedron Lett., 1991, 32, 5445.
12. W. Adam and A. Schonberger, Tetrahedron Lett., 1992, 33, 53.
13. B. C. Challis and A. R. Butler, in The Chemistry of the Amino Group, ed. S. Patai, Interscience, London, 1968, pp. 320–347, and references therein.
14. H. E. de la Mare, J. Org. Chem., 1960, 25, 2114; L. A. Harris and J. S. Olcott, J. Am. Oil Chem. Soc., 1966, 43, 11.
15. L. Kuhnen, Chem. Ber., 1966, 99, 3384.
16. A. H. Kuthier, K. Y. Al-Mallah, S. Y. Hanna and N. A. I. Abdulla, J. Org. Chem., 1987, 1710.
17. The differences in the results with methyl iodide from those recorded in the literature (ref. 21) may be a function of the different reaction conditions or the lack of sensitivity of the method of analysis.
18. L. P. Hammett, J. Am. Chem. Soc., 1937, 59, 76.
19. C. H. Brown and Y. Okamato, J. Am. Chem. Soc., 1958, 80, 4979 It is possible that a conjugative effect could be significant in an electron transfer mechanism.
20. Note the lower correlation coefficient also for the Okamoto–Brown plot for cumene oxidation (ref. 4).
21. K. B. Wiberg, Physical Organic Chemistry, Wiley, New York, 1964, pp. 379, 405.
22. W. Adam, G. Asensio, R. Curci, M. E. González-Núñez and R. Mello, J. Org. Chem., 1992, 57, 953.
23. R. W. Murray and D. Gu, J. Chem. Soc., Perkin Trans. 2, 1993, 2203.
24. R. W. Murray and D. Gu, J. Chem. Soc., Perkin Trans. 2, 1994, 461.
25. J. P. Lorand, J. L. Anderson, Jr., B. P. Shafer and D. L. Verral II, J. Org. Chem., 1993, 58, 1560.
26. B. A. Marples, J. P. Muxworthy and K. H. Baggaley, Tetrahedron Lett., 1991, 32, 533.
27. W. Adam and A. K. Smerz, Tetrahedron, 1995, 51, 13 039.
28. K. Miaskiewicz, N. A. Teich and D. A. Smith, J. Org. Chem., 1997, 62, 6493.
29. W. Adam, R. Curci, L. D'Accolti, A. Dinnoi, C. Fusco, F. Gasparini, R. Kluge, R. Paredes, M. Schulz, A. K. Smerz, L. A. Veloza, S. Weinkotz and R. Winde, Chem. Eur. J., 1997, 3, 105.
30. W. Adam, J. Bialas and L. Hadjiarapoglou, Chem. Ber., 1991, 124, 2377.
31. G. W. Gribble and C. F. Nutaitis, Synthesis, 1987, 709.
32. (a) N,N-Dimethyl-4-methoxyaniline: D. G. Thomas, J. H. Billman and C. E. Davis, J. Am. Chem. Soc., 1946, 68, 895; (b) N,N-dimethyl-4-chloroaniline, D. P. Evans and R. Williams, J. Chem. Soc., 1939, 1199.
33. M. Ferrer, F. Sanchez-Baez and A. Messegner, Tetrahedron, 1997, 53, 15 877.