Thermal fragmentation reactions of 1,4,2-dithiazines and 1,4,2,5-dithiadiazines in the presence of dienophiles: synthesis of 1,4-dithiine derivatives. X-Ray crystal structures of a 1,4,2-dithiazine 1,1-dioxide and a 1,4,2,5-dithiadiazine derivative

Abstract

The reaction of 5,6-dimethyl-3-(4-bromophenyl)-1,4,2-dithiazine 1b with dimethyl acetylenedicarboxylate (DMAD) at 180 °C in o-dichlorobenzene affords a mixture of thiophene derivative 5 and isothiazole derivative 6: the former probably via the zwitterionic adduct 3 and dithiine derivative 4, neither of which are isolable; the latter by sulfur extrusion from 1b. Reaction of norbornene with 1b affords dithiine derivative 7. Oxidation of 1b with meta-chloroperoxybenzoic acid yields the 1,1-dioxide derivative 8, the X-ray crystal structure of which is reported. The efficient synthesis of 3-aryl-6-methylthio-1,4,2,5-dithiadiazine derivatives 12a–c by ring expansion of 1,4,2-dithiazolium salts 11a–c with an iodine–ammonia reagent is described. Reaction of 12c with DMAD at 180 °C affords the stable dithiine derivative 14, probably via the intermediate 1,4,2-dithiazine 13. Electrochemical oxidation of 12a–c is irreversible, yielding 1,4,2,5-dithiadiazinium cation radicals at potentials [E ^ox = 1.55–1.73 V (vs. Ag/AgCl)] which are sensitive to the electronic nature of the para-substituent on the aryl ring. The X-ray crystal structure of 12b is reported.

References

1. (a) R. T. Oakley, Prog. Inorg. Chem., 1988, 38, 299; (b) M. A. Gray and C. W. Rees, J. Chem. Soc., Perkin Trans. 1, 1993, 3077 and earlier parts of the series.
2. (a) M. R. Bryce, G. R. Davison, J. A. K. Howard and A. S. Batsanov, J. Chem. Soc., Chem. Commun., 1992, 478; (b) M. R. Bryce, G. R. Davison, A. S. Batsanov and J. A. K. Howard, J. Chem. Soc., Perkin Trans. 1, 1992, 2295; (c) M. R. Bryce, G. R. Davison and S. Gough, J. Chem. Soc., Perkin Trans. 1, 1994, 2571.
3. J. Nakayama, H. Fukushima, R. Hashimoto and M. Hoshino, J. Chem. Soc., Chem. Commun., 1982, 612.
4. For a review of 1,4-dithiine chemistry, see K. Kobayashi and C. L. Gajural, Sulfur Rep., 1986, 7, 123.
5. K. Kobayashi and K. Mutai, Tetrahedron Lett., 1978, 10, 905.
6. (a) B. G. Lenz and B. Zwandenburg, J. Chem. Soc., Chem. Commun., 1984, 1386; (b) J. M. M. Smith, P. T. Beurskens, B. G. Lenz and B. Zwandenburg, Acta Crystallogr., Sect. C, 1985, 41, 1086.
7. K. Yonemoto, I. Shibuya and K. Honda, Bull. Chem. Soc. Jpn., 1988, 61, 2232.
8. K. Yonemoto and I. Shibuya, Chem. Lett., 1989, 89.
9. For syntheses of 1,4,2-dithiazolium salts, see (a) D. J. Greig, M. McPherson and R. M. Paton, J. Chem. Soc., Perkin Trans. 1, 1985, 1205; (b) D. J. Greig, M. McPherson, R. M. Paton and J. Crosby, J. Chem. Soc., Chem. Commun., 1985, 696; (c) I. Shibuya and K. Yonemoto, Bull. Chem. Soc. Jpn., 1986, 59, 2017; (d) F. S. Y. Chen, M. P. Sammes and R. L. Harlow, J. Chem. Soc., Perkin Trans. 1, 1988, 899.
10. (a) S. T. A. K. Daley, C. W. Rees and D. J. Williams, J. Chem. Soc., Chem. Commun., 1984, 57; (b) S. T. A. K. Daley and C. W. Rees, J. Chem. Soc., Perkin Trans. 1, 1987, 207; (c) J. Sundermeyer, H. W. Roesky and M. Noltenmeyer, Angew. Chem., 1989, 101, 609; Angew. Chem., Int. Ed. Engl., 1989, 28, 609.
11. (a) H. Hopff and J. van der Chrone, Chimia, 1959, 13, 107; (b) T. Sone, Y. Abe and T. Oikawa, Nippon Kagaku Zasshi, 1971, 92, 1193; (c) J. Nakayama, M. Kashiwagi, R. Yomoda and M. Hoshino, Nippon Kagaku Kaishi, 1987, 1414.
12. G. Bandoli, C. Panattoni, D. A. Clemente, E. Tondello, A. Dondoni and A. Mangini, J. Chem. Soc. B, 1971, 1407.
13. H. A. Levi and R. J. Doedens, Acta Crystallogr., Sect. B, 1980, 36, 1959.
14. S. L. Gusinskaya, V. Telly and T. P. Makagonova, Khim. Geterotsikl. Soedin., 1970, 3, 345.
15. G. M. Sheldrick, SHELXTL, Structure Determination Software Programs, ver. 5/VMS, Siemens Analytical X-Ray Instruments Inc., Madison, Wisconsin, USA, 1995.
16. H. D. Flack, Acta Crystallogr., Sect. A, 1983, 39, 876.