8α-OH马尾杉碱B的结构鉴定——NMR谱分析及密度泛函理论研究

Structure Assignment of 8α-OH Phlegmariurine B——A Combined NMR and Density Functional Theory Investigation

从千层塔中分离得到了一新生物碱,图谱分析不能确定其相对构型,为此我们运用量子化学密度泛函方法对其进行了NMR理论计算.核磁共振理论模拟表明,8α-OH马尾杉碱B的化学位移值与实验值吻合得非常好.同时,理论研究与COSY,NOESY谱图的对照,以及偶合常数的分析、取代基效应的分析都进一步确证了该化合物的结构.此外我们的研究还表明,NMR的量子化学计算为天然产物的结构鉴定提供了一种新的工具.

A combined NMR and density functional theory (B3LYP) investigation was carried out on a new alkaloid obtained from Huperzia serrata Thunb(Trev. ) . The theoretical NMR data of 8α- OH phlegmariurine B are in excellent agreement with the experimental results. The configuration was then established through analysis of the vicinal coupling constants and 2D NMR(NOESY and COSY) spectra.This work shows that the quantum chemistry study of NMR can serve as a promising tool in aiding structural assignment of natural products.