Abstract
The title compound, C18H22N2O5S, is largely planar, with an r.m.s. deviation of 0.0546 (1) angstrom of atoms from the mean plane through all non-H atoms except for the methyl groups. The benzene and pyrimidinedione rings are inclined to one another at a dihedral angle of 1.41 (7)degrees. In the crystal, weak C-H...O interactions connect the molecules into chains propagating along the b-axis direction.