Structure of a Triterpene Extracted from Austroplenckia populnea (Celastraceae), Methyl 3-Oxofriedelan-20a-oate

C31H5oO3, Mr=470-74, orthorhombic, P21212~, a = 6.815 (2), b = 16.127 (3), c = 24-695 (4) A, V = 2714 (2) A 3, Z = 4, Dx = 1.152 gcm -3, A(Mo Ka) = 0.71073 A, /z = 0.668 cm-i, F(000) = 1040, T = 298 K, R = 0-055 for 1454 observed reflections. The rings adopt chair conformations. The bond angles are as expected within exPerimental error and the mean sp 2 and sp 3 bond angles are 120.0 (4) and 111.1 (3) °, respectively. Experimental. The data-collection and refinement parameters are summarized in Table 1.