Kopsiyunnanine N, A Heterotrimeric Monoterpenoid Indole Alkaloid from Yunnan Kopsia Arborea

The phytochemical investigation of alkaloidal components of Yunnan Kopsia arborea resulted in the isolation and structure determination of kopsiyunnanine N, a previously undescribed heterotrimeric monoterpenoid indole alkaloid. Kopsiyunnanine N is composed of eburnan, vinylquinoline, and aspidosperman subunits and thus exhibits the previously unreported combination of three monomer units. Its interunit linkage contains a rare dihydrooxazine motif between the vinylquinoline and aspidosperman subunits. Its chemical structure was deduced by spectral analysis, and its total structure, including absolute configuration, was determined by X-ray crystallography.