3-(1,3-Di-phenyl-propan-2-yl)-4-methyl-6-phenyl-isoxazolo[3,4-d]pyridazin-7(6H)-one.

In the title compound, C27H23N3O2, the geminal benzyl groups branching out from the methine adjacent to the isoxazole group are both syn-oriented to the methyl group of the pyridazinone moiety, as reflected by C—C distances of 3.812 (2) and 4.369 (2) A between the methyl carbon and the nearest ring carbon of each benzyl group. This kind of conformation is retained in CDCl3 solution, as evidenced by distinct phenyl-shielding effects on the 1H NMR signals of the methyl H atoms. The isoxazolo[3,4-d]pyridazin ring system is virtually planar (r.m.s. deviation from planarity = 0.031 A), but the N-bonded phenyl group is inclined to the former by an ring–ring angle of 55.05 (3)°. In the crystal, the T-shaped mol­ecules are arranged in an inter­locked fashion, forming rod-like assemblies along [10-1]. The mol­ecules are held together by unremarkable weak C—H⋯N, C—H⋯O and C—H⋯π inter­actions (C—O,N,C > 3.4 A), while significant π–π-stacking inter­actions are absent.