Aspidospermine tabersonine group

Tabersonine (XCII), an amorphous base which occurs in the seeds of Amsonia tabernaemontana (65, Volume VII, p. 134), in some Stem-madenia species (66, 66a), and in Tabernaemontana alba (66a), is a member of a distinct group of aspidospermine-type alkaloids which bear an extra carbon atom in the form of a carbomethoxyl group linked to position 3. The other members of this group are described briefly in Section II, P and in detail in Chapter 12. 

Aspidospermine-Aspidofractine-Eburnamine Group. The leaves of Pandaca minutiftora contain (+)-vincadifformine, which also occurs in the leaves of Amsonia tabernaemontana, together with ten other alkaloids [tabersonine, (+)-l,2-dehydroaspidospermidine, (—)-quebrachamine, lochnericine, ( ) and (—)-vincadine, (-)and ( )-epivincadine, (+)-14,15-dehydrovincadine, and (+)-14,15-dehydroepivincadine] the roots contain the first four alkaloids and ebumamonine. 

---