Vacuum–thermal fragmentation and ring cleavage of 1-(N-substituted-pyrrol-2-yl)-3-tosyltriazene tetraalkylammonium salts to 4-cyano-1-azabuta-1,3-dienes

Abstract

N-Methyl- and N-phenyl-4-cyano-1-azabuta-1,3-diene (1a and 1b respectively) are produced by vacuum–thermal fragmentation and ring cleavage of 1-(N-substituted-pyrrol-2-yl)-3-tosyltriazene tetraalkylammonium salts, prepared by reaction of the corresponding 2-lithiopyrroles with tosyl azide and successive reaction of the resulting lithium triazene salts with tetraalkylammonium bromide.

References

1. P. Spagnolo and P. Zanirato, J. Org. Chem., 1978, 43, 3539; M. Funicello, P. Spagnolo and P. Zanirato, Acta Chem. Scand., 1993, 47, 231 and references cited therein.
2. D. Spinelli and P. Zanirato, J. Chem. Soc., Perkin Trans. 2, 1993, 1129.
3. M. T. Di Gioia, E. Foresti, D. Nanni and P. Zanirato, Gazz. Chim. Ital., 1995, 125, 151.
4. S. Gronowitz and P. Zanirato, J. Chem. Soc., Perkin Trans. 2, 1994, 1815.
5. For information about the chemistry of organic azides (and nitrenes) the reader is referred to the following useful books and reviews; E. F. V. Scriven and K. Turnbull, Chem. Rev., 1988, 88, 297; E. F. V. Scriven, Azides and Nitrenes: Reactivity and Utility, Academic Press, New York, 1984; S. Patai, The Chemistry of the Azido Group, Interscience Publishers, London, 1971.
6. N. Gjøs and S. Gronowitz, Acta Chem. Scand., 1971, 25, 2526.
7. R. H. Smith Jr., B. D. Wladkowski, J. A. Herling, T. D. Pfaltzgraff, B. Pruski, J. R. Klose and C. J. Michejda, J. Org. Chem., 1992, 57, 654; R. H. Smith Jr., B. D. Wladkowski, J. A. Herling, T. D. Pfaltzgraff, J. E. Taylor, E. J. Thompson, B. Pruski, J. R. Klose and C. J. Michejda, J. Org. Chem., 1992, 57, 6448; D. W. Farnsworth, D. A. Wink, N. M. Roscher, C. J. Michejda and R. H. Smith Jr., J. Org. Chem., 1994, 59, 5942.
8. J. Becher and W. Dehaen, Acta Chem. Scand., Ser. B, 1993, 47, 244 and references cited therein.
9. D. L. Boger and S. N. Weinreb, ‘Azabutadienes’, in Hetero Diels–Alder Methodology in Organic Synthesis, ed. H. H. Wasserman, Academic Press, San Diego, 1987, vol. 47, p. 239.
10. N. J. Sisti, A. I. Motorina, M.-E. T. H. Dau, C. Riche, F. W. Fowler and D. S. Grierson, J. Org. Chem., 1996, 61, 3715.
11. D. A. Shirley, B. H. Gross and P. A. Roussel, J. Org. Chem., 1955, 20, 225.