Demethyl(trifluoromethyl)actinomycins, II: Bis(trifluoromethylated) 4-(2′-benzoxazolyl)actinocin derivatives

Liebigs Annales

Volumn , Issue 5, 1997, Pages 999-1003

  Bahner, Isabel ^a   Lackner, Helmut ^a  

^a UNIVERSITY OF GÖTTINGEN   (Germany)

Author keywords

Actinomycins; Antibiotics; Heterocycles; NMR spectroscopy; Trifluoromethyl actinocins

Indexed keywords

EID: 33749104926     PISSN: 09473440     EISSN: None     Source Type: Journal    
DOI: 10.1002/jlac.199719970531     Document Type: Article

References (23)

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4. Angew. Chem. Int. Ed. Engl. 1975, 14, 375-386;
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7. I. Bahner, Diploma Thesis, University of Göttingen, 1995.
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9. M. Hauptschein, E. A. Nodiff, A. J. Saggiomo, J. Am. Chem. Soc. 1954, 76, 1051-1054.
10. Model compound: 4-(Trifluoromethyl)benzoic acid. - Methods: DCC, DCC/N-hydroxysuccinimide or 1-hydroxybenzotriazole, oxalyldiimidazolide, acid chloride etc.
11. As the oxidation reaction becomes very slow (4-methyl analogues are oxidized within seconds), the quantity and the composition of the products depend on different parameters, e.g. the reaction time. Under special conditions the yield of 8a can improve to 80-90%.
12. The 9a acid, probably also formed, is unstable and decarboxylates to 9b.
13. 15N) = -140; M. Witanowski, G. A. Webb, Nitrogen NMR, Plenum Press, London and New York, 1973, p. 213.
14. 15N-labelled actinocinyl peptides (H. Lackner, K. H. Kerber, unpublished results). Typical J values are 5.8, 3.2, 4.9, 6.1 and 17.6 Hz for N-10 → C-9, 9a, 10a, 1 and 2-N → C-2.
15. 15N couplings along a hydrogen bond.
16. 19F through-space coupling constants on the F,F distance has recently been studied by L. Ernst, K. Ibrom, Angew. Chem. 1995, 107, 2010-2012;
17. Angew. Chem. Int. Ed. Engl. 1995, 34, 1881-1882.
18. 3 groups. Steric effects seem to be dominant.
19. [1] leads to normal actinocinyl compounds of type 2!
20. [3]).
21. E. Forche in Methoden Org. Chem. (Houben-Weyl) 4th ed. 1962, vol. 5/3, p. 481.
22. 3, by lithiation of 4-(trifluoromethyl)benzaldehyde dimethylacetal were unsuccessful.
23. J. Meienhofer, J. Org. Chem. 1967, 32, 1143-1145.