The new alkaloids flavinantine (I; R¹= R³= Me, R²= H) and flavinine (I; R¹= R²= H, R³= Me), along with sinoacutine (II; R¹= H, R²= Me) and norsinoacutine (II; R¹= R²= H) have been isolated from C. flavens. Isolation procedures and work leading to structural elucidation are described. Studies on the acid rearrangement of some norsinoacutine derivatives are also reported.