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J. Jakupovic G. Schmeda-hirschmann A. Schuster C. Zdero F. Bohlmann R.M. King H. Robinson J. Pickardt 《Phytochemistry》1985,25(1):145-158
The investigation of nine Vernonia species afforded in addition to known sesquiterpenes 28 new ones. The structures were elucidated by high field 1H NMR spectroscopy and the configurations were determined by NOE difference spectroscopy and, in one case, by X-ray analysis. The results indicated that configurations of several previously reported sesquiterpene lactones have had to be revised. In addition to known types two new ones, the jalcaguaianolides and the vernojalcanolides, are described. Furthermore some unusual reaction products are presented which, in part, led to some natural occurring lactones. 相似文献
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Ferdinand Bohlmann Lutz Müller Rajinder K. Gupta Robert M. King Harold Robinson 《Phytochemistry》1981,20(9):2233-2237
Out of the nineteen species of Vernonia studied, five contained highly oxygenated sesquiterpene lactones, while the rest contained predominantly triterpenes, especially lupane derivatives. 相似文献
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The investigation of Stokesia laevis afforded in addition to known compounds five new sesquiterpene lactones, four hirsutinolides and one guaianolide. The structures are very similar to those isolated from several Vernonia species. Since hirsutinolides have only been previously isolated from this latter genus, these results suggest that Stokesia may be closely related to Vernonia. 相似文献
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The investigation of Vernonia compactiflora afforded in addition to known compounds a hirsutinolide and a glaucolide; the latter is most probably the direct precursor of the former. The aerial parts of V. monocephala contain the same hirsutinolide as well as the corresponding acetate, while those of V. chalybaea afforded glaucolide B. A reinvestigation of the aerial parts of V. cotoneaster gave in addition to the allenic lactone isolated before two further known ones as well as a new glaucolide. The structures of the lactones were elucidated by spectroscopic methods and some chemical transformations. The erroneously assigned stereochemistry at C-10 in the hirsutinolides has been revised. The biogenetic relationship of the Vernonia lactones is discussed briefly. 相似文献
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The investigation of two Bolivian Vernonia species afforded, in addition to known compounds, five further enollactones of the hirsutinolide type and a new hydroxyzaluzanine. The structures were elucidated by intensive 1H NMR studies and some chemical transformations. The results show again that the hirsutinolides are probably of chemotaxonomic importance in the large genus Vernonia. 相似文献
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