Crystal structure of 3,13-dimethoxy-5,6,10,11-tetrahydrofuro[3,4-i][5]helicene-7,9-dione.

The title compound, C26H20O5, crystallizes with two independent molecules (A and B) in the asymmetric unit, which differ primarily in the location of the -OCH3 groups. In the crystal, the mol-ecules form a layered structure parallel to (10-1) by C-H⋯O hydrogen-bonded networks. Adjacent layers are also linked by further C-H⋯O hydrogen bonds, forming a three-dimensional structure.