Synthesis and crystal structure of 5-(3,4-dimethoxyphenyl)-1-phenyl-3- hydroxypyrazole

The title compound (C₁₇H₁₆N₂O₃) has been prepared by the oxidation of 1,5-diarylpyrzolidin-3-one with oxygen in the presence of FeCl₃, and its structure was characterized by elemental analysis, IR, ¹H NMR and X-ray single-crystal diffraction analysis. The crystal belongs to triclinic, space group P1̄ with a = 6.6600(13), b = 8.4200(17), c =14.060(3) Å, α = 85.61(3), β = 76.89(3), γ = 81.18(3)°, Z = 2, D_c = 1.298 g/cm ³, μ = 0.090mm^-1, F(000) = 312, R = 0.048 and wR = 0.1231. X-ray analysis revealed that there exist a large conjugation system in the pyrazole ring, a stable enol form and intermolecular hydrogen bonding as well as network structure in the crystal.