Agladupols A–E, Triterpenoids from Aglaia duperreana

Three new apotirucallane-type triterpenoids, agladupols A–C (<b>1</b>–<b>3</b>), and two new tirucallane-type triterpenoids, agladupols D and E (<b>4</b> and <b>5</b>), along with four known compounds, were isolated from the leaves and stems of Aglaia duperreana (Meliaceae). The structures of compounds <b>1</b>–<b>5</b> were elucidated by spectroscopic data. A <sup>13</sup>C 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-<i>O</i>-methyltoosendanpentol (<b>1a</b>), a known compound with the relative configurations of the stereocenters in the side chain undetermined, was completely assigned.