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 The structures of four new diterpene alkaloids, spiramines A, B, C, and D. New Diterpene Alkaloids from the Roots of Spiraea japonica New Diterpene Alkaloids from the Roots of <i>Spiraea </i><i>japonica</i> 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