Cyclorocaglamide, the first bridged cyclopentatetrahydrobenzofuran, and a related "open chain" rocaglamide derivative from Aglaia oligophylla
Cyclorocaglamide, the first bridged cyclopentatetrahydrobenzofuran, and a related "open chain" rocaglamide derivative from Aglaia oligophylla
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DOI：
10.1021/np020291k
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发表时间：
2003-01-01
影响因子：
5.1
通讯作者：
Proksch, P
中科院分区：
文献类型：
--
作者：
Bringmann, G;Mühlbacher, J;Proksch, P
从热带植物Aglaia oligophylla中分离出两种与rocaglamide有关的天然产物，即已知的化合物6-去甲氧基-10-羟基-11-甲氧基-6，7-亚甲基二氧基rocaglamide（3）和其8 β，10-脱水类似物cyclorocaglamide（4）。化合物4是第一个桥连的环五氢苯并呋喃天然产物，并且它表现出与迄今为止已知的所有其他罗格列胺天然产物几乎相反的CD光谱，但它在基本分子框架的所有立体中心处仍然具有相同的绝对构型。量子化学CD计算明确地表明了这一点（这里基于分子动力学加权力场结构），并最终通过实验证实，通过3的“仿生型”环化得到4，预期CD光谱的“反转”。3和4的相反的手性性质，尽管它们具有同手性特征，但强调了最小心地处理手性数据的必要性，例如，通过量子化学CD计算来模拟它们。化合物3在针对棉贪夜蛾的新生幼虫进行评价时表现出2.5ppm的LC 50，而4在该测定中高达100 ppm是无活性的。
Two rocaglamide-related natural products, the previously known compound 6-demethoxy-10-hydroxy11-methoxy-6,7-metfiylendioxyrocaglamide (3), and cyclorocaglamide (4), its 8b,10-anhydro analogue, have been isolated from the tropical plant Aglaia oligophylla. Compound 4 is the first bridged cyclopentatetrahydrobenzofuran natural product, and it exhibited a CD spectrum virtually opposite that of all the other rocaglamide natural products known so far, but it still has the same absolute configuration at all stereogenic centers of the basic molecular framework. This was shown unequivocally by quantum chemical CD calculations (here based on molecular dynamics-weighted force field structures) and was finally confirmed experimentally, by a "biomimetic-type" cyclization of 3 to give 4, with the expected "inversion" of the CD spectrum. The opposite chiroptical properties of 3 and 4, despite their homochiral character, underline the necessity of handling chiroptical data with the greatest care, e.g., by simulating them by quantum chemical CD calculations. Compound 3 exhibited an LC50 of 2.5 ppm when evaluated against neonate larvae of Spodoptera littoralis, while 4 was inactive in this assay up to 100 ppm.