The structure of catharinensine isolated from Peschiera catharinensis was deduced from a detailed analysis of its 1H NMR, 13C NMR and mass spectra. The synthesis of 17-demethoxyrhynchophylline confirmed its structure, and led us to suggest the configuration allo A for catharinensine. Coronaridine, isovoacangine, heyneanine, 16-epiaffinine, decarbomethoxyvoacamine and conodurine were also isolated. © 1984.