Structural Revision of Four Spiramine Diterpenoid Alkaloids from the Roots of Spiraea Japonica

Abstract

On the basis of detailed ¹H-NMR, ¹³C-NMR spectral analysis, especially by 2D NMR experiments (¹H-¹H COSY, HMQC, HMBC, and NOESY) as well as by chemical transformations, four isoatisine type diterpenoid alkaloids, spiramines P and Q, and U and T, have been reassigned as the 6β hydroxyl and 6β acetoxyl substituents, respectively, rather than the previously assigned 15α counterparts in our further studies on chemical constituents of the roots of Spiraea japonica var. acuta.

Key Words:

• Spiraea japonica var. acuta
• Rosaceae
• Diterpenoid alkaloids
• Structural revision