Absolute Configuration and Conformational Analysis of Brevipolides, Bioactive 5,6-Dihydro-伪-pyrones from Hyptis brevipes

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• 作者：G. Alejandra Su谩rez-Ortiz ; Carlos M. Cerda-Garc铆a-Rojas ; Adriana Hern谩ndez-Rojas ; Rogelio Pereda-Miranda
• 刊名：Journal of Natural Products
• 出版年：2013
• 出版时间：January 25, 2013
• 年：2013
• 卷：76
• 期：1
• 页码：72-78
• 全文大小：319K
• 年卷期：v.76,no.1(January 25, 2013)
• ISSN：1520-6025

文摘

The (6鈥?i>S)-configuration of brevipolides A鈥揓 (1鈥?b>10), isolated from Hyptis brevipes, was established by X-ray diffraction analysis of 9 in conjunction with Mosher鈥檚 ester analysis of the tetrahydro derivative 11 obtained from both geometric isomers 8 and 9 as well as by chemical correlations. The structure of the new brevipolide J (10) was characterized through NMR and MS data as having the same 6-heptyl-5,6-dihydro-2H-pyran-2-one framework possessing the cyclopropane moiety of all brevipolides but substituted by an isoferuloyl group instead of the p-methoxycinnamoyl moiety found in 8 and 9. Conformational analysis of these cytotoxic 6-heptyl-5,6-dihydro-伪-pyrones was carried out on compound 9 by application of a protocol based on comparison between experimental and DFT-calculated vicinal ¹H鈥?sup>1H NMR coupling constants. Molecular modeling was used to correlate minimum energy conformers and observed electronic circular dichroism transitions for the isomeric series of brevipolides. Compounds 7鈥?b>10 exhibited moderate activity (ED₅₀ 0.3鈥?.0 渭g/mL) against a variety of tumor cell lines.