9-(3,4-Dimethoxyphenyl)-3,3,6,6-tetramethyl-1,2,3,4,5,6,7,8,9,10-decahydroacridine-1,8-dione

The asymmetric unit of the title compound, C 25 H 31 NO 4 , contains two independent molecules. In one molecule, the benzene ring and an attached methoxy group were refined as disordered over two sets of sites in a 0.65 (4): 0.35 (4) ratio. In both molecules, the central ring of the acridinedione system adopts a flattened boat conformation. The four essentially planar atoms of this ring [maximum deviations = 0.006 (5) Å in both molecules] forms dihedral angles of 86.8 (2) and 87.6 (2)°, respectively, with the major and minor components in the disordered benzene ring and 87.3 (2)° with the benzene ring in the fully ordered molecule. The two outer rings of the acridinedione system adopt sofa conformations in both molecules. In the crystal, N—H...O hydrogen bonds form two independent chains along [100]. C—H...O hydrogen bonds link the chains, forming a three-dimensional network.