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

The title compound congestiflorone, C₂₈H₃₂O₄, which was isolated from the stem bark of Mesua congestiflora, consists of a benzophenone skeleton with two attached pyran rings to which a cyclo­hexane 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 cyclo­hexane 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 intra­molecular O—H...O hydrogen bond is observed. In the crystal, mol­ecules are linked via C—H...O inter­actions.

4-{(E)-2-[4-(But-3-en-1-yl­oxy)phen­yl]diazen-1-yl}benzoic acid

The title compound, C₁₇H₁₆N₂O₃, has an E conformation about the azobenzene (–N=N–) linkage. The benzene rings are twisted slightly with respect to each other [6.79 (9)°], while the dihedral angle between the plane through the carb­oxy group and the attached benzene ring is 3.2 (2)°. In the crystal, mol­ecules are oriented with the carb­oxy groups head-to-head, forming O—H...O hydrogen-bonded inversion dimers. These dimers are connected by C—H...O hydrogen-bonds into layers lying parallel to the (013) plane.

1-[4-(Prop-2-en-1-yl­oxy)benz­yl]-2-[4-(prop-2-en-1-yl­oxy)phen­yl]-1H-benzimidazole

In the title compound, C₂₆H₂₄N₂O₂, the benzimidazole ring system is almost planar [maximum displacement = 0.025 (1) Å] and makes dihedral angles of 80.48 (5) and 41.57 (5)° with the benzene rings, which are inclined to one another by 65.33 (6)°. In the crystal, mol­ecules are linked via C—H...π and weak π–π inter­actions [centroid–centroid distance = 3.8070 (7) Å and inter­planar distance = 3.6160 (5) Å].