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 A New C20-Diterpene Alkaloid, Spirasine III and the Interconversion of Oxazolidine Ring Four New C20-Diterpene Alkaloids, Spirasine I, Spirasine II, Spirasine VII and Spirasine VIII from Spiraea japonica The Structures of Four New Diterpene Alkaloids: Spirasines XII-XV New Diterpene Alkaloids from the Roots of Spiraea japonica New Diterpene Alkaloids from the Roots of <i>Spiraea </i><i>japonica</i> The structures of four new diterpene alkaloids, spiramines A, B, C, and D. 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 spirasine V and spirasine VI