EFFICIENT SYNTHESIS OF FUSED ISOTHIAZOLO C-NUCLEOSIDES. III. SYNTHESIS OF 7-SUBSTITUTED ISOTHIAZOLO[4,5-d]PYRIMIDINE C-NUCLEOSIDES* |
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| Abstract: | The Divakar-Reese procedure has been successfully applied for transforming 7-oxo-isothiazolo4,5-d]pyrimidine C-nucleosides (4a,b, 5a,b, 6a) via 1,2,4-triazol-1-yl intermediates (7a,b, 8a,b) into various 7-substituted C-nucle- osides 15a,b, 16a,b, 17a, 18a, 19a,b, 20a,b; their subsequent deprotection provides novel types of unusual C-glycosides 22b, 23a, 24a,b, 25b, 26b. C-Nucleosides, possessing on its heterocyclic base other than naturally occuring oxo- or amino substituents, are important model compounds for biological or medicinal studies 2a] Hanessian, S. and Pernet, A. G. 1976. Adv. Carbohydr. Chem. Biochem., 32: 111–188. cf. Google Scholar], 2b] Mizuno, Y. 1986. The Organic Chemistry of Nucleic Acids Amsterdam: Elsevier. Google Scholar], 2c] Huryn, D. M. and Okabe, M. 1992. Chem. Rev., 92: 1745–1768. Crossref], Web of Science ®] , Google Scholar], 2d] Häbich, D. 1991. Chem. in uns. Zeit, 25: 295–307. Google Scholar], 2e] Uhlmann, E. and Peyman, A. 1990. Chem. Rev., 90: 543–584. Crossref], Web of Science ®] , Google Scholar], 2f] Thuong, N. T. and Helene, C. 1993. Angew. Chem., 105: 697–723. Crossref] , Google Scholar], 2g] 1993. Angew. Chem. Int. Ed. Engl., 33: 666–690. Google Scholar], 2h] Yarchoan, R., Mitsuya, H., Zhomas, R. V., Pluda, J. M., Hartman, N. R., Perno, C. F., Marczyk, K. S., Allain, J. P., Johns, D. G. and Broder, S. 1989. Science, 245: 412–414. Crossref], PubMed], Web of Science ®] , Google Scholar], 2i] Tanaka, H., Baba, M., Hayakawa, H., Sakamaki, T., Miyasaka, T., Ubasawa, M., Takashima, H., Sekiya, E., Nitta, I., Shigeta, S., Walker, R. T., Balzarini, J. and De Clerq, E. 1991. J. Med. Chem., 34: 349–357. Crossref], PubMed], Web of Science ®] , Google Scholar] 3a] Koyama, G., Maeda, K., Umezawa, H. and Iitaka, Y. 1966. Tetrahedron Lett., : 597–602. Some C-glycosides with antibiotic, antiviral (HIV), and anticancer activities Google Scholar], 3b] Hori, M., Wakashiro, T., Ito, E., Sawa, T., Takeuchi, T. and Umezawa, H. J. 1968. J. Antibiot., 21A: 264–270. Chem. Abstr. 1968, 69, 11356j] Google Scholar], 3c] Farkas, J. and ?orm. 1972. F. Collect. Czech. Chem. Commun., 37: 2798–2803. Google Scholar], 3d] Acton, E. M., Ryan, K. J., Henry, D. W. and Goodman, L. 1971. J. Chem. Soc., Chem. Commun., : 986–988. Google Scholar], 3e] Nakagawa, Y., Kano, H., Tsukuda, Y. and Koyama, H. 1967. Tetrahedron Lett., : 4105–4109. Google Scholar], 3f] Inoue, I. and Kuwaijama, I. 1980. J. Chem. Soc., Chem. Commun., : 251–253. Google Scholar], 3g] Buchanan, J. G., Stobie, A. and Wightman, R. H. 1980. ibid., : 916–917. Crossref] , Google Scholar], 3h] Hildebrand, S. and Leumann, C. 1996. Angew. Chem., 108: 2100–2102. Angew. Chem. Int. Ed. Engl. 1996, 35, 1968–1970 Google Scholar]. We want to report on the synthesis of novel 7-substituted isothiazolo = 4,5-d]pyrimidine C-nucleosides. As we could show in previous papers 1] Wamhoff, H., Berressem, R. and Nieger, M. 1994. J. Org. Chem., 59: 1912–1917. Part 2 Google Scholar], 4] Wamhoff, H., Berressem, R. and Nieger. 1993. M. J. Org. Chem., 58: 5181–5185. Google Scholar], there exists a simple approach to the protected C-glycosides 4–6. |
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