Macrocyclische Spermidinalkaloide aus Pleurostylia africana LOES. 9. Mitteilung über Celastraceen‐Inhaltsstoffe

Macrocyclic Spermidine Alcaloids from Pleurostylia africana L OES . The structure of pleurostyline, a new macrocyclic spermidine alkaloid from Pleurostylia africana (Celastraceae) , has been elucidated mainly by 1 H‐ and 13 C‐NMR.‐spectroscopy. Pleurostyline represents a new structure type in which spermidine is incorporated in a 13‐membered lactam ring to which an additional cinnamoyl residue is fused to yield a 7‐membered ring. The same plant contains also the spermidine alkaloids celacinnine and cellallocinnine of which 13 C‐ and high field 1 H‐NMR.‐measurements have been carried out for the first time. Both alkaloids are interconvertible by UV.‐irradiation. In addition the existence of rotational isomerism of one amide group of these alkaloids has been demonstrated by NMR.‐spectroscopy.