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.