RE-DISTRIBUTION OF THE N-METHYL GROUP IN GELSEMINE

The N_(b)-bromomethyl derivative (2) of gelsemine,a quaternary ammonium salt,was found to be recalcitrant toward Hofmann type alkaline degradation which has been successful in other cases.Instead,a re-distribution of the N-methyl group took place,giving rise to 3a,1,3b and 3c,in descending order of R_f values.

钩吻生物碱的提取分离及结构鉴定

中草药钩吻中具有抗癌活性生物碱单体成分的提取分离,并测定其结构。方法:药材粉碎后用3%NaOH碱化后,晾干,用氯仿浸泡,回收氯仿提取液得浸膏。加酸溶解后,用氯仿萃取,碱化水层,再用氯仿萃取,得到钩吻总生物碱。然后经硅胶柱层析、反相ODS柱层析以及制备型HPLC层析分离纯化,并经理化性质和光谱学数据的测定鉴定单体化合物的结构。结果:共分离得到12个单体化合物,经测定紫外光谱、1H-NMR数据并与文献报道相比较,初步确定两个化合物的结构分别为gelsemine和koumine。结论:通过硅胶柱层析、ODS柱层析和HPLC相结合的方法可以达到分离钩吻总生物碱的目的。