Hydrochloric Acid → 5-Methoxy-4-oxo-1-phenyl-1,4-dihydropyridazine-3-carboxylic acid

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Reaction Steps

To a suspension of methyl 5-methoxy-4-oxo-1-phenyl-1,4-dihydropyridazine-3-carboxylate (39.04 g) in methanol (663 mL) was added dropwise 1N sodium hydroxide (300 mL) with stirring under ice-cooling, and the mixture was allowed to warm to room temperature and stirred for 1 hr. 1N Hydrochloric acid (300 mL) was added dropwise with stirring under ice-cooling, and the mixture was stirred at the same temperature for 1 hr. The precipitated crystals were collected by filtration, washed successively with water, ethanol/diisopropyl ether (1/2), and diisopropyl ether, and dried to give the title compound (36.1 g) as pale-yellow crystals.

Provenance & Evidence