Agladupols A–E, Triterpenoids from Aglaia duperreana

Three new apotirucallane-type triterpenoids, agladupols A–C (13), and two new tirucallane-type triterpenoids, agladupols D and E (4 and 5), along with four known compounds, were isolated from the leaves and stems of Aglaia duperreana (Meliaceae). The structures of compounds 15 were elucidated by spectroscopic data. A 13C NMR-based general rule for assignment of the C-21 configuration in the side chain of apotirucallane- and tirucallane-type triterpenoids was proposed. According to this, the relative stereochemistry of 21-O-methyltoosendanpentol (1a), a known compound with the relative configurations of the stereocenters in the side chain undetermined, was completely assigned.