Reactions of the alkyl radical attached to the ring nitrogen of 2-phenylthio-indole, -benzimidazole and -uracil

Abstract

Alkyl radicals have been generated on the 1-N-alkyl group of 2-phenylthioindole, 2-phenylthiobenzimidazole and 6-phenylthiouracil derivatives. These N-alkyl radicals have been generated from the corresponding N-alkyl bromides by the action of triphenyltin hydride–azoisobutyronitrile, triphenyltincobaloxime or by the photolysis of the corresponding N-alkylcobaloxime. Reaction modes differ little with the method of radical generation except for the substantial formation of alkyl phenyl sulfide, a radical substitution product of the alkylcobaloximes, in the photolysis of the cobaloximes. The cobaloxime(II) species, which exists in the reaction system N-alkyl bromide–triphenyltincobaloxime, activates the phenylthio group for the radical substitution, and the lack of the tin hydride makes it possible for the reaction to occur at a higher concentration than the reaction with the hydride reagent.

References

1. (a) R. T. Brown, J.-C. Cai, G. A. Cordell, W. G. Creasey, G. Grethe, R. B. Herbert, H.-P. Husson, C. R. Hutchinson, J. A. Joule, J. E. Saxton and M. R. Uskovic, The Chemistry of Heterocyclic Compounds, vol. 25, Part IV, ed. J. E. Saxton, John Wiley and Sons, New York, 1972; (b) N. Alvarez, H.-J. Borschberg, W. A. Creasey, R. B. Herbert, K. Honty, J. A. Joule, M. Lounasmaa, G. Massiot, A. Nemes, J. Sapi, J. E. Saxton, C. Szantay, A. Tolvanen, R. Verpoote, M. E. Wall and M. C. Wani, Supplement to vol. 25, Part VI, ed. J. E. Saxton, John Wiley and Sons, New York, 1994.
2. (a) R. J. Sundberg, Comprehensive Heterocyclic Chemistry, vol. 4, ch. 3.06, ed. C. W. Bird and G. W. H. Cheeseman, Pergamon, Oxford, 1984; (b) ch. 9 of references 1a and 1b.
3. (a) W. A. Remers and R. K. Browns, The Chemistry of Heterocyclic Compounds, vol. 25, Part I, ed. W. J. Houlihan, John Wiley and Sons, New York, 1972; (b) R. J. Parry, J. C. Powers, K. Rush, L. R. Smith and F. Troxler, vol. 25, Part II, ed. W. J. Houlihan, John Wiley and Sons, New York, 1972; (c) W. A. Remers and T. F. Spande, vol. 25, Part III, ed. W. J. Houlihan, John Wiley and Sons, New York, 1979.
4. D.-K. Kim, Y.-W. Kim and K. H. Kim, J. Heterocycl. Chem., 1997, 34, 311.
5. F. E. Ziegler and M. Belema, J. Org. Chem., 1994, 59, 7962 and references cited therein.
6. Y. Antonio, Ma. E. De La Cruz, E. Galeazzi, A. Guzman, B. L. Bray, R. Greenhouse, L. J. Kurz, D. A. Lustig, M. L. Maddox and J. M. Muchowski, Can. J. Chem., 1994, 72, 15.
7. A. P. Dobbs, K. Jones and K. T. Veal, Tetrahedron Lett., 1995, 36, 4857.
8. C. J. Moody and C. L. Norton, Tetrahedron Lett., 1995, 36, 9051.
9. S. Ozaki, S. Mitoh and H. Ohmori, Chem. Pharm. Bull., 1996, 44, 2020.
10. (a) S. Caddick, K. Aboutayab and R. I. West, J. Chem. Soc., Chem. Commun., 1995, 1353; (b) S. Caddick, K. Aboutayab, K. Jenkins and R. I. West, J. Chem. Soc., Perkin Trans. 1, 1996, 675.
11. F. Aldabbagh and W. R. Bowman, Tetrahedron Lett., 1997, 38, 3793.
12. M. Tada and H. Nakagiri, Tetrahedron Lett., 1992, 33, 6657.
13. (a) M. Tada, T. Nakamura and M. Matsumoto, J. Am. Chem. Soc., 1988, 110, 4647; (b) M. Tada and K. Kaneno, Chem. Lett., 1995, 843; (c) M. Tada, T. Yoshihara and K. Sugano, J. Chem. Soc., Perkin Trans. 1, 1995, 1941; (d) M. Tada, K. Sugano and T. Yoshihara, Bull. Chem. Soc. Jpn., 1995, 68, 2969.
14. M. Tada and R. Shino, J. Inorg. Biochem., 1991, 44, 89.
15. J. E. Baldwin, J. Chem. Soc., Chem. Commun., 1976, 734.
16. A. L. J. Beckwith, C. J. Easton and A. K. Serelis, J. Chem. Soc., Chem. Commun., 1980, 482.
17. L. Lusztyk, B. Maillard, S. Deycard, D. A. Lindsay and K. U. Ingold, J. Org. Chem., 1987, 52, 3509.
18. A. L. J. Beckwith and G. Moad, J. Chem. Soc., Chem. Commun., 1974, 472.
19. G. N. Schrauzer, L. P. Lee and J. W. Sibert, J. Am. Chem. Soc., 1970, 92, 2997.
20. B. T. Golding, T. J. Kemp and H. H. Sheena, J. Chem. Res., 1981, (S), 34; (M), 334.
21. R. D. N. Rao and M. C. R. Symons, J. Chem. Soc., Faraday Trans. 1, 1984, 80, 423.
22. P. Huston, J. H. Espenson and A. Bakac, J. Am. Chem. Soc., 1992, 114, 9510; Organometallics, 1992, 11, 3165.
23. P. Hamel, Y. Girard and J. G. Atkinson, J. Org. Chem., 1992, 57, 2694.
24. S. Nakajima, I. Tanaka, T. Seki and T. Anno, Yakugaku Zasshi, 1958, 78, 1378.
25. R. W. Shortridge, R. A. Craig, K. W. Greenlee, J. M. Derfer and C. E. Boord, J. Am. Chem. Soc., 1948, 70, 946.
26. R. F. Brown and N. M. Van Gulick, J. Am. Chem. Soc., 1955, 77, 1089.
27. F. Yoneda, K. Tsukuda, M. Kawazoe, A. Sano and A. Koshiro, J. Heterocycl. Chem., 1981, 18, 1329.
28. G. N. Schrauzer, Inorganic Syntheses, vol. XI, p. 61, McGraw-Hill, New York, 1968.