Four New C20-Diterpene Alkaloids, Spirasine I, Spirasine II, Spirasine VII and Spirasine VIII from Spiraea japonica

Four New C20-Diterpene Alkaloids, Spirasine I, Spirasine II, Spirasine VII and Spirasine VIII from Spiraea japonica A New C20-Diterpene Alkaloid, Spirasine III and the Interconversion of Oxazolidine Ring A New C20-Diterpene Alkaloid, Spirasine III and the Interconversion of Oxazolidine Ring Two New Diterpenoid Alkaloids from Spiraea japonica L. f. var. fortunei(Planchon) Rehd. The structures of four new diterpene alkaloids, spiramines A, B, C, and D. The Structures of Four New Diterpene Alkaloids: Spirasines XII-XV New Diterpene Alkaloids from the Roots of <i>Spiraea </i><i>japonica</i> New Diterpene Alkaloids from the Roots of Spiraea japonica Diterpene alkaloids from roots of Spiraea japonica Three New Diterpene Alkaloids from Spiraea japonica