Alkaloid studies. Part LXI. The structure of twelve new alkaloids from Aspidosperma cylindrocarpon

Twelve new alkaloids have been isolated from Aspidosperma cylindrocarpon; six (IX, X, and XIV–XVII) belong to a new series of aspidospermine-type with 20-hydroxy- and 21-carboxymethyl groups. These compounds differ in the nature of their N-acyl substituents (formyl, acetyl, benzoyl, cinnamoyl, and dihydrocinnamoyl). The demethoxy (VIII), N-formyl (V), N-benzoyl (VI), and N-methyl (VII) analogues of cylindrocarpidine (III) were also found, together with the unsubstituted compound which is now named ‘cylindrocarine’(IV) to facilitate the nomenclature of its derivatives. In addition N-formyl (XIX) and N-acetyl (XX) cylindrocarpinol were characterized.