2-Hydroxy-1,6,7,8-tetramethoxy-3-methylanthraquinone

Abstract

The title compound, C19H18O7, 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. © 2008 International Union of Crystallography.