Acetic Acid → 1-(3-Bromo-2-fluorophenyl)-5-methoxy-3-(1-phenyl-1H-pyrazol-5-yl)pyridazin-4(1H)-one

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Reaction Steps

A mixture of 3-acetyl-1-(3-bromo-2-fluorophenyl)-5-methoxypyridazin-4(1H)-one (2.98 g, 8.74 mmol) in N,N-dimethylformamide dimethyl acetal (30 mL) was heated to reflux for 3.5 h. The mixture was concentrated in vacuo. To the residue were added AcOH (30 mL) and phenylhydrazine (1.72 mL, 17.5 mmol). The mixture was heated to reflux for 4 h. The mixture was diluted with 1 M HCl aqueous solution, extracted with AcOEt, washed with saturated NaHCO3 aqueous solution, dried over Na2SO4, filtered, concentrated in vacuo, purified by column chromatography on basic silica gel (hexane/AcOEt=50/50 to 0/100) and recrystallized with EtOH to yield the title compound (2.29 g, 59% yield) as a yellow solid: mp 186-191° C. 1H NMR (DMSO-d6, 300 MHz): δ ppm 3.77 (3H, s), 6.99 (1H, d, J=1.9 Hz), 7.08-7.15 (1H, m), 7.17-7.26 (1H, m), 7.28-7.47 (5H, m), 7.74-7.86 (2H, m), 8.55 (1H, d, J=2.3 Hz). Anal. Calcd for C20H14H14BrFN4O2: C, 54.44; H, 3.20; N, 12.70. Found: C, 54.70; H, 3.30; N, 12.82.

Provenance & Evidence