Four new cassane diterpenoid amides from Erythrophleum suaveolens [(Guill. et Perr.), Brenan]

- Four new cassane diterpenoids amide were isolated from Erythrophleum suaveolens.
- The absolute configuration of the main stereogenic centers was performed by the X-ray structural analysis.
- The configuration of the exo-cyclic double bond was confirmed as E.