3-(1,3-Diphenylpropan-2-yl)-4-methyl-6-phenylisoxazolo[3,4-d] pyridazin-7(6H)-one

In the title compound, C₂7H₂3N₃O ₂, 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)Å 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 Å), 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 > 3.4A), while significant π-π-stacking interactions are absent.