organic compounds
The title compound, C17H18O5, was isolated from the leaves of Rauwenhoffia siamensis Scheff. There are two crystallographically independent molecules in the asymmetric unit. The dihedral angle between the two benzene rings is 80.81 (7)° in one molecule and 65.89 (7)° in the other. The symmetry-related molecules are linked via O—HO intermolecular hydrogen bonds to form chains along [201].
organic compounds
The non-H atoms of the title compound, C15H10O4, which was isolated from the roots of Prismatomeris malayana Ridl., are coplanar. Intramolecular O—HO and C—HO hydrogen bonds are observed in the molecular structure. The molecules form centrosymmetric hydrogen-bonded dimers via intermolecular O—HO hydrogen bonds. The crystal structure is further stabilized by weak π–π interactions.
organic compounds
The title compound, C17H14O4, a homoisoflavanoid, was isolated from the twigs and stems of Caesalpinia digyna Rottler. The pyran ring adopts an envelope conformation. The symmetry-related molecules are linked via O—HO and C—HO intermolecular hydrogen bonds to form a molecular network.