1-Methyl-2-(4-methyl-phen-yl)-4-morpholinopyridazine-3,6(1H,2H)-dione.

The structure analysis of the title compound, C(16)H(19)N(3)O(3), has been undertaken in order to facilitate the inter-pretation of (1)H and (13)C NMR data and to determine the position of the morpholine residue in this nucleophilic substitution product. The main result is that the morpholine group, with a chair conformation, is connected at the 4-position of the pyridazine ring. The benzene and pyridazine rings make a dihedral angle of 62.17 (5)°. Mol-ecules are linked into a two-dimensional network by non-classical C-H⋯O hydrogen bonds, in which O atoms serve as double or triple acceptors.