title: 2-Hydr-oxy-1,6,7,8-tetra-meth-oxy-3-methyl-anthraquinone.
abstract: The title compound, C(19)H(18)O(7), also known as chrysoobtusin, was isolated from Cassia tora L. (Leguminosae). The anthraquinone ring system is almost planar, the dihedral angle between the two benzene rings being 4.27 (4)°. The structure is stabilized by intra- and inter-molecular O-H⋯O and C-H⋯O hydrogen bonds, and by weak π-π stacking inter-actions along the b axis, with a centroid-centroid distance between related benzene rings of 3.800 (4) Å.
authors.affiliation: College of Light Industry and Food Sciences, South China University of Technology, Guangzhou 510641, People's Republic of China.
authors.forename: Li-Cai
authors.initials: LC
authors.lastname: Zhu
authors.forename: Zhen-Gang
authors.initials: ZG
authors.lastname: Zhao
authors.forename: Shu-Juan
authors.initials: SJ
authors.lastname: Yu