1-Hydroxybenzotriazole → N,5-dimethoxy-N-methyl-4-oxo-1-phenyl-1,4-dihydropyridazine-3-carboxamide

Participants

Reaction Conditions

Reaction Steps

Under an argon atmosphere, 5-methoxy-4-oxo-1-phenyl-1,4-dihydropyridazine-3-carboxylic acid (40 g) was dissolved in dimethylacetamide (600 mL) by heating to 50° C., and ice-cooled. With stirring, N,O-dimethylhydroxylamine hydrochloride (23.7 g), 1-hydroxybenzotriazole (21.9 g) and 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide hydrochloride (46.6 g) were added, and triethylamine (81.4 mL) was added, and the mixture was allowed to warm to room temperature and stirred for 96 hr. To the reaction mixture was added ethyl acetate, and an insoluble material was filtered off. The filtrate was concentrated under reduced pressure to dryness, and the residue was purified by NH silica gel column chromatography (ethyl acetate/methanol) to give the title compound (39.2 g) as white crystals.

Provenance & Evidence