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.