Xylogranatins F–R: Antifeedants from the Chinese Mangrove,Xylocarpus granatum, A New Biogenetic Pathway to Tetranortriterpenoids
作者:Jun Wu、Si Zhang、Torsten Bruhn、Qiang Xiao、Haixin Ding、Gerhard Bringmann
DOI:10.1002/chem.200700663
日期:2008.1.28
Thirteen limonoids with a new carbon skeleton, the xylogranatins F-R (1-13), have been isolated from the seeds of a Chinese mangrove, Xylocarpus granatum; two recently reported compounds, xylogranatins C and D were also isolated. Their structures were elucidated on the basis of spectroscopic data and chemical methods. The absolute configurations of these compounds were determined by using the modified
从中国红树林种子木果(Xylocarpus granatum)的种子中分离出了十三种具有新碳骨架的柠檬苦素,即木葡聚糖(FR)(1-13)。还分离了两种最近报道的化合物木葡聚糖酶C和D。根据光谱数据和化学方法阐明了它们的结构。这些化合物的绝对构型是通过使用改良的Mosher MTPA酯法和量子化学圆二色性(CD)计算确定的。木糖素FQ是自然界中发现的第一个芳香族B环柠檬苦素。它们属于两个亚结构类别,其中一个(1-3)包含吡啶环,而另一个(4-12)包含中央呋喃核。木葡聚糖C和R可被视为关键的生物合成中间体,而木葡聚糖D,到目前为止,发现的唯一柠檬素类化合物具有碳骨架并带有C(30)-C(9)键,显然是人工产物。这些化合物的结构暗示了四降三萜类化合物的新生物遗传途径。发现木糖素F,G和R对Mythimna separata(Walker)的三龄幼虫表现出明显的拒食活性,浓度为1 mg mL(