Hydrochloric Acid → 1-[2-Fluoro-4-(trifluoromethoxy)phenyl]-5-methoxy-4-oxo-1,4-dihydropyridazine-3-carboxylic acid

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Reaction Steps

To a solution of methyl 1-[2-fluoro-4-(trifluoromethoxy)phenyl]-5-methoxy-4-oxo-1,4-dihydropyridazine-3-carboxylate (3.4 g, 9.3 mmol) in THF (150 mL) was added 1 M NaOH aqueous solution (14 mL, 14 mmol), and the mixture was stirred at room temperature for 30 min. The mixture was acidified with 1 M HCl aqueous solution and concentrated under reduced pressure. The residue was diluted with AcOEt, washed with water and brine, dried over MgSO4, filtered and concentrated under reduced pressure to give the title compound (3.2 g, 97% yield) as a pale yellow amorphous solid: 1H NMR (300 MHz, DMSO-d6): δ ppm 3.88 (3H, s), 7.52-7.59 (1H, m), 7.86 (1H, dd, J=10.8, 2.5 Hz), 7.97 (1H, t, J=8.7 Hz), 8.91 (1H, d, J=1.1 Hz), 14.83 (1H, brs).

Provenance & Evidence