(E)-4-[(1,5-Dimethyl-3-oxo-2-phenyl-2,3-dihydro-1H-pyrazol-4-yl)iminomethyl]-2-methoxyphenyl 4-bromobenzenesulfonate

In the title compound, C25H22BrN3O5S, the central benzene ring makes dihedral angles of 4.41 (10), 67.09 (9) and 62.05 (10)°, respectively, with the pyrazolone, bromobenzene and terminal phenyl rings. The dihedral angle between the pyrazolone and phenyl rings is 57.75 (11)°. In the crystal, two pairs of C—H⋯O hydrogen bonds link the molecules into inversion dimers. A weak intramolecular C—H⋯O hydrogen bonds is also observed.

In the title compound, C 25 H 22 BrN 3 O 5 S, the central benzene ring makes dihedral angles of 4.41 (10), 67.09 (9) and 62.05 (10) , respectively, with the pyrazolone, bromobenzene and terminal phenyl rings. The dihedral angle between the pyrazolone and phenyl rings is 57.75 (11) . In the crystal, two pairs of C-HÁ Á ÁO hydrogen bonds link the molecules into inversion dimers. A weak intramolecular C-HÁ Á ÁO hydrogen bonds is also observed.
Structural information is useful when investigating the coordination properties of Schiff bases functioning as ligands.

Experimental
An anhydrous ethanol solution (50 ml) of 4-formyl-2-methoxyphenyl 4-bromobenzenesulfonate (3.71 g, 10 mmol) was added to an anhydrous ethanol solution (50 ml) of 4-amino-1,5-dimethyl-2-phenylpyrazol-3-one (2.03 g, 10 mmol) and the mixture stirred at 350 K for 3 h under N 2 , giving a yellow precipitate. The product was isolated, recrystallized from acetonitrile, and then dried in a vacuum to give pure compound (I) in 83% yield. Yellow single crystals of (I) suitable for X-ray analysis were obtained by slow evaporation of an acetonitrile solution.

Refinement
The H atoms were included in calculated positions and refined using a riding model approximation. Constrained C-H bond lengths and isotropic U parameters: 0.93 Å and U iso (H) = 1.2U eq (C) for Csp 2 -H; 0.96 Å and U iso (H) = 1.5U eq (C) for

Figure 1
The molecular structure of the title compound, with displacement ellipsoids for non-H atoms drawn at the 50% probability level. 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 > 2σ(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.