Abstract
Pachysantermine-A is one of the minor alkaloids of Pachysandra terminalis SIEB. et ZUCC., a Buxaceous plant, and the structure including absolute configuration of pachysantermine-A is now assigned to the formula Ia. It is unique in that it has a seven-membered ring ester grouping containing a nitrogen atom. Also a biogenetic pathway of pachysantermine-A (Ia) in the living plant and of pachystermine-A (VIIa) and -B (VIIb), which are the closely related alkaloids, was presumed.
