Hydrochloric Acid → 1-(4-Bromo-2,5-difluorophenyl)-5-methoxy-4-oxo-1,4-dihydropyridazine-3-carboxylic acid

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Reaction Steps

A solution of methyl 1-(4-bromo-2,5-difluorophenyl)-5-methoxy-4-oxo-1,4-dihydropyridazine-3-carboxylate (25 g, 68 mmol) and 2 M NaOH aqueous solution (68 mL) in EtOH (68 mL) was stirred at room temperature overnight. The solvent was removed by evaporation and resulting aqueous solution was acidified by 6 M HCl aqueous solution (12 mL). The precipitate was collected by filtration and azeotroped with toluene to give the title compound (25 g, 100% yield) as a brown solid: LC-MS (ESI) m/z 376 [M+H]+.

Provenance & Evidence