一种新的DENUDATINE型C_(20)二萜生物碱结构的NMR研究

NMR STUDIES ON THE STRUCTURE OF A NEW DENUDATINE DITERPENOID-TYPE ALKALOID

从内蒙西伯利亚乌头中分离得一个新的C20二萜生物碱，采用选择性远程DEPT，同核和异核二维NMR技术相结合进行了研究，其结构确定为Lepenine的C－11基向立体异构体，定名为11a－hydroxylapenine．结果表明，选择性远程DEPTNMR技术对于连接这类化合物中被季碳和杂原子分割的NMR自旋体系，测定基本骨架和确定信号归属都有独到之处．

A new C20 diterpenoid alkaloid has been isolated from Aconitum barbatum var.hispidum Ledeb. Its structure has been elucidated as (1) using a combination of the selectivelong-range DEPT, homo-and heteronuclear 2D NMR techniques. The results showed thaiselective long-range DEPT NMR technique is very effective and convenient for the connection of 1H NMR spin systems separated by quaternary carbons and heteroatoms and assignment of NMR spectra of this class of compounds. Compoud (1) is a epimer of the knowncompound lepenine (2) at C-11 and named as 11a-hydroxy lepenine.