Tetranortriterpenoids and related compounds. Part 22. New apo-tirucallol derivatives and tetranortriterpenoids from the wood and seeds of <i>Chisocheton paniculatus</i> (Meliaceae)

Five new compounds, the apo-tirucallol derivatives (1), (9), (13), and (16) and the tetranortriterpenoid vilasinin 1,3-diacetate (18), have been isolated from the wood of Chisocheton paniculatus (Meliaceae). From the seeds of the same tree four new tetranortriterpenoids have been obtained, including the γ-lactone (22), the hemiacetal (23), the γ-hydroxybutenolide (24), and 17β-hydroxy-6α-acetoxynimbinin (26). Compounds (22) and (23) are possible precursors of normal furanoid tetranortriterpenoids. 13C and 1H n.m.r. data for these nine compounds are reported