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DOI: 10.1039/A807273F (Paper) Reference Section for: J. Chem. Soc., Perkin Trans. 2, 1999, 877-884

Conformational assignments and a nitrogen inversion process in some 3-acyloxy-1,3-oxazinanes by NMR and X-ray analysis

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Syed M. A. Hashmi, Mohammed I. M. Wazeer, M. Sakhawat Hussain, Joseph H. Reibenspies, Herman P. Perzanowski and Sk. Asrof Ali

Abstract

The stereochemistry of the preferred conformers of several 3-acyloxy-1,3-oxazinanes has been established by NMR spectroscopy. A strong anomeric effect stabilizes the conformation having an equatorial orientation of the lone pair on nitrogen. A nitrogen inversion process was found to be the rate-limiting process in the conformational equilibria. The range of ΔG[hair space] ‡ values was found to be 60–71 kJ mol–1. Solid state structures as determined by X-ray diffraction confirm the findings of the NMR study.

References

  1. A. R. Katrizky, V. J. Baker and F. M. S. Brito-palma, J. Chem. Soc., Perkin Trans. 2, 1980, 1739 RSC.
  2. Y. Y. Samitov, O. I. Danilova, B. V. Unkovsky and I. P. Boiko, Magn. Reson. Chem., 1986, 24, 480.
  3. F. G. Riddlell and J. M. Lehn, J. Chem. Soc. (B), 1968, 1224 RSC.
  4. Y. Allingham, R. C. Cookson, T. A. Crabb and S. Vary, Tetrahedron, 1968, 24, 4625 CrossRef CAS.
  5. T. A. Crabb and S. I. Judd, Org. Magn. Reson., 1970, 2, 317 Search PubMed.
  6. T. A. Crabb and R. F. Newton, Tetrahedron, 1968, 24, 4423 CrossRef CAS.
  7. F. G. Riddell, Tetrahedron, 1981, 37, 849 CrossRef CAS.
  8. C. L. Perrin, J. D. Thoburn and S. Elsheimer, J. Org. Chem., 1991, 56, 7034 CrossRef CAS.
  9. S. M. A. Hashmi, Sk. A. Ali and M. I. M. Wazeer, Tetrahedron, 1998, 54, 12959 CrossRef CAS.
  10. Sk. A. Ali, S. M. A. Hashmi and M. I. M. Wazeer, Spectrochim. Acta, Part A, in the press Search PubMed.
  11. R. U. Lemieux and S. Koto, Tetrahedron, 1933, 30, 1974.
  12. A. J. Kirby, The Anomeric Effect and Related Stereoelectronic Effects at Oxygen, Springer, Berlin, 1983 Search PubMed.
  13. J. E. Anderson and J. E. T. Corrie, J. Chem. Soc., Perkin Trans. 2, 1992, 1027 RSC.
  14. Sk. A. Ali, A. Hasan and M. I. M. Wazeer, J. Chem. Soc., Perkin Trans. 2, 1996, 1479 RSC.
  15. P. J. Chivers and T. A. Crab, Tetrahedron, 1970, 26, 3389 CrossRef CAS.
  16. N. K. Wilson and J. B. Stothers, Top. Stereochem., 1974, 8, 4 Search PubMed.
  17. T. B. Grindley, Tetrahedron Lett., 1982, 1757 CrossRef CAS.
  18. The NMR program Library, Science and Engineering Research Council, Daresbury Laboratory, Cheshire, UK.
  19. M. I. M. Wazeer, H. A. Al-Muallem and Sk. A. Ali, J. Phys. Org. Chem., 1993, 6, 326 CAS.
  20. J. Sandstrom, Dynamic NMR Spectroscopy, 1982, Academic Press, London Search PubMed.
  21. M. I. M. Wazeer, S. M. A. Hashmi and Sk. A. Ali, Can. J. Anal. Sci. Spectrosc., 1997, 42, 190 Search PubMed.
  22. Siemens (1990b) XSCANS Program for reduction of data collected on Siemens R3 m/v diffractometers. Siemens Analytical X-ray Inst. Inc, Madison, WI, USA.
  23. G. Sheldrick, 1993, SHELXL-93 Program for Crystal Structure Refinement, Anorganische Chemie der Universitat, Tammanstrasse 4, D-3400 Gottingen, Germany.
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