| 论文题目: | Spiroketals of Pestalotiopsis fici Provide Evidence for a Biosynthetic Hypothesis Involving Diversified Diels-Alder Reaction Cascades |
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| 作者: | Liu Ling, Li Yan, Li Li, Cao Ya, Guo Liangdong, Liu Gang, Che Yongsheng |
| 联系作者: | Cao Ya, Che Yongsheng |
| 刊物名称: | The Journal of organic chemistry |
| 期: | 7 |
| 卷: | 78 |
| 页: | 2992-3000 |
| 年份: | 2013 |
| 影响因子: | 4.204 |
| 论文下载: | |
| 摘要: | Chloropestolides B-G (1-6), six new metabolites featuring the chlorinated spiro[benzo[d][1,3]dioxine-2,7'-bicyclo[2.2.2]octane]-4,8'-dione (1-3) and spiro[benzo[d][1,3]dioxine-2,1'-naphthalene]-2',4-dione (4-6) skeletons, and their putative biosynthetic precursor dechloromaldoxin (7) were isolated from the scale-up fermentation cultures of the plant endophytic fungus Pestalotiopsis fici . The structures of 1-7 were determined mainly by NMR experiments. The absolute configurations of 1-3 were deduced by analogy to the previously isolated metabolites from the same fungus (9 and 13-18), whereas those of 4, 5, and 7 were assigned by electronic circular dichroism (ECD) calculations. Structurally, the spiroketal skeletons found in 1-3 and 4-6 could be derived from 2,6-dihydroxy-4-methylbenzoic acid with chlorinated bicyclo[2.2.2]oct-2-en-5-one and 4a,5,8,8a-tetrahydronaphthalen-2(1H)-one, respectively. Biogenetically, compounds 1-6 were derived from the same Diels-Alder precursors as the previously isolated 9 and 12-18. In addition, compounds 2 and 3 were proposed as the biosynthetic intermediates of 17 and 16, respectively. Compound 1 was cytotoxic to three human tumor cell lines. |
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