Isopalhinine A, a Unique Pentacyclic Lycopodium Alkaloid from Palhinhaea cernua

A new pentacyclic (5/6/6/6/7) Lycopodium alkaloid named isopalhinine A (1), which possesses a sterically congested architecture built with a tricyclo[4.3.1.03,7]decane (isotwistane) moiety and a 1-azabicyclo[4.3.1]decane moiety, and palhinines B (2) and C (3) were isolated from Palhinhaea cernua. The structure and absolute configuration of 1 were elucidated by a combination of NMR spectra, optical rotation calculation, and X-ray diffraction experiment. A possible biogenetic pathway was also proposed.

一种新的五环（5/6/6/6/7）型石杉碱类化合物，命名为异帕立宁A（1），其具有空间位阻性显著的立体结构，由三环[4.3.1.03,7]癸烷（异扭烷）基团和1-氮杂双环[4.3.1]癸烷基团构建而成。同时，从蕨类植物Palhinhaea cernua中分离出帕立宁B（2）和C（3）。通过核磁共振波谱、旋光率计算以及X射线衍射实验相结合，阐明了化合物1的结构及其绝对构型。同时，提出了其可能的生物合成途径。