Crystal structure of 13-(2-meth-oxy-phenyl)-3,4-di-hydro-2H-indazolo[1,2-b]phthalazine-1,6,11(13H)-trione.

In the title compound, C22H18N2O4, the three fused rings of the pyrazolo-phthalazine moiety are coplanar (r.m.s. deviation = 0.027 Å). The cyclo-hexene ring fused to the pyrazolidine ring, so forming the indazolophthalazine unit, has a half-chair conformation. The benzene ring is almost normal to the mean plane of the pyrazolo-phthalazine moiety, with a dihedral angle of 87.21 (6)° between their planes. In the crystal, mol-ecules are linked by pairs of C-H⋯O hydrogen bonds forming inversion dimers. The dimers are linked via C-H⋯π inter-actions, forming slabs parallel to (100). Between the slabs there are weak π-π inter-actions [shortest inter-centroid distance = 3.6664 (9) Å], leading to the formation of a three-dimensional structure.