6-Benzyloxy-2-phenylpyridazin-3(2H)-one

In the title compound, C17H14N2O2, the central pyridazine ring forms dihedral angles of 47.29 (5) and 88.54 (5)° with the benzene rings, while the dihedral angle between the benzene rings is 62.68 (6)°. In the crystal, molecules are linked by two weak C—H⋯O hydrogen bonds and three weak C—H⋯π interactions.

In the title compound, C 17 H 14 N 2 O 2 , the central pyridazine ring forms dihedral angles of 47.29 (5) and 88.54 (5) with the benzene rings, while the dihedral angle between the benzene rings is 62.68 (6) . In the crystal, molecules are linked by two weak C-HÁ Á ÁO hydrogen bonds and three weak C-HÁ Á Á interactions.
As a continuation of our studies on the crystal structures of Pyridazinone analogues (Ju et al., 2011), we report here the synthesis and crystal structure, an ellipsoid plot of which is shown in Fig. 1. The central pyridazine ring forms dihedral angles of 47.29 (5)° and 88.54 (5)° with the two benzene rings, while the dihedral angle between the two benzene rings is 62.68 (6)°. The structure is stabilized by two weak C-H···O and three C-H···Cg intermolecular hydrogen bonds (Cg's: centroids of the benzene rings) (Table 1).

Experimental
3-hydroxyl-1phenyl-6-pyridazone(0.94 g, 5 mmol), benzyl chloride(0.63 g, 5 mmol) and K 2 CO 3 (0.69 g, 5 mmol) were added to absolute ethanol(30 ml). The mixture was stirred in the room temperature for 10 h. The suspension was filtered and the residue was washed with absolute ethanol. The title compound was recrystallized from the mother solution and single crystals of (I) were obtained by slow evaporation.

Refinement
All H atoms were placed in calculated positions, with C-H = 0.95 Å and C-H = 0.99 Å, and included in the final cycles of refinement using a riding model, with U iso (H) = 1.2Ueq(C).

Computing details
Data collection: CrystalClear (Rigaku/MSC, 2005); cell refinement: CrystalClear (Rigaku/MSC, 2005); data reduction: CrystalClear (Rigaku/MSC, 2005); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: SHELXTL (Sheldrick, 2008); software used to prepare material for publication: CrystalStructure (Rigaku/MSC, 2005  The asymmetric unit of the title compound, (I), with displacement ellipsoids drawn at the 30% probability level. where P = (F o 2 + 2F c 2 )/3 (Δ/σ) max < 0.001 Δρ max = 0.29 e Å −3 Δρ min = −0.20 e Å −3 Special details Geometry. All e.s.d.'s (except the e.s.d. in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell e.s.d.'s are taken into account individually in the estimation of e.s.d.'s in distances, angles and torsion angles; correlations between e.s.d.'s in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell e.s.d.'s is used for estimating e.s.d.'s involving l.s. planes. Refinement. Refinement of F 2 against ALL reflections. The weighted R-factor wR and goodness of fit S are based on F 2 , conventional R-factors R are based on F, with F set to zero for negative F 2 . The threshold expression of F 2 > σ(F 2 ) is used only for calculating R-factors(gt) etc. and is not relevant to the choice of reflections for refinement. R-factors based on F 2 are statistically about twice as large as those based on F, and R-factors based on ALL data will be even larger.