A grayanotox-9(11)-ene derivative from Rhododendron brachycarpum and its structural assignment via a protocol combining NMR and DP4 plus application
作者:Nguyen Quoc Tuan、Joonseok Oh、Hyun Bong Park、Daneel Ferreira、Sanggil Choe、Juseon Lee、MinKyun Na
DOI:10.1016/j.phytochem.2016.10.010
日期:2017.1
A grayanotox-9(11)-ene derivative along with five known diterpenoids, were isolated from the MeOH extract of R. brachycarpum. Extensive 1D and 2D NMR experiments were conducted to establish the 2D structure and relative configuration of the grayanotox-9(11)-ene derivative. Comparison of simulated and experimental ECD spectra resulted in an inconclusive outcome to assign its absolute configuration.
越来越多的证据表明计算方法在天然产物的结构表征中的有用作用。短果杜鹃传统上用于控制糖尿病、肝炎、高血压和类风湿性关节炎,在韩国被列为濒危物种。从 R. brachycarpum 的 MeOH 提取物中分离出一种grayanotox-9(11)-ene 衍生物以及五种已知的二萜。进行了广泛的 1D 和 2D NMR 实验以建立 Grayanotox-9(11)-ene 衍生物的 2D 结构和相对构型。模拟和实验 ECD 光谱的比较导致分配其绝对配置的不确定结果。或者,包括规范的原子轨道 (GIAO) NMR 化学位移计算,在先进的统计方法 DP4 plus 的支持下,采用酸水解来建立其绝对构型。这项工作举例说明了 NMR 分析与量子力学计算相结合如何成为替代 X 射线晶体学或手性光学方法来完成微量丰度分子结构分配的可行方法。