title: rac-[3-Hydroxy-6,9-dimethyl-6-(4-methylpent-3-en-1-yl)-6a,7,8,9,10,10a-hexahydro-6H-1,9-epoxybenzo[c]chromen-4-yl](phenyl)methanone.
abstract: The title compound congestiflorone, C(28)H(32)O(4), which was isolated from the stem bark of Mesua congestiflora, consists of a benzophenone skeleton with two attached pyran rings to which a cyclo-hexane ring and a C6 side chain are bonded. The benzene ring is significantly distorted from planarity (r.m.s. deviation = 0.0007 Å) due to the constraints imposed by junctions with the two pyran rings. The cyclo-hexane ring is in a chair conformation, one pyran ring is in a boat conformation, while the other is a distorted chair. The phenyl and benzene rings make a dihedral angle of 55.85 (9)°. An intra-molecular O-H⋯O hydrogen bond is observed. In the crystal, mol-ecules are linked via C-H⋯O inter-actions.
authors.forename: Gwendoline Cheng Lian
authors.initials: GC
authors.lastname: Ee
authors.forename: Soek Sin
authors.initials: SS
authors.lastname: Teh
authors.forename: Huey Chong
authors.initials: HC
authors.lastname: Kwong
authors.forename: Mohamed Ibrahim
authors.initials: MI
authors.lastname: Mohamed Tahir
authors.forename: Siau Hui
authors.initials: SH
authors.lastname: Mah