(20S *,24S *)-25-Hydroxy-20,24-epoxy-A-homo-4-oxadammaran-3-one (Chrysura) isolated from the leaves of Walsura chrysogyne.

• Main Authors: Mahmod, Ilya Iryani, Huey, Chong Kwong, Mohamed Tahir, Mohamed Ibrahim, Ismail, Intan Safinar
• Format: Article
• Language: English; English
• Published: International Union of Crystallography 2011
• Online Access: http://psasir.upm.edu.my/id/eprint/25048/1/20S.pdf; http://psasir.upm.edu.my/id/eprint/25048/; http://www.iucr.org/

The title dammarane triterpenoid, C30H50O4, assigned the name chrysura, was isolated from an ethyl acetate extract of Walsura chrysogyne leaves (Meliaceae). It has 20S*,24S* relative stereochemistry and an oxepanone ring with two methyl groups at position 4. The two cyclo­hexane rings adopt chair conformations. The cyclo­pentane and tetra­hydro­furan rings have envelope conformations; their mean planes make a dihedral angle of 13.1 (3)°, indicating that the rings are only slightly tilted with respect to each other. There is an intra­molecular C—H(...)O hydrogen bond in the mol­ecule, which forms S(6) and S(7) ring motifs. In the crystal, mol­ecules are linked via O—H(...)O and C—H(...)O hydrogen bonds, forming chains propagating along [001] which stack along the b-axis direction.