Acetonitrile → 5-methoxy-3-(1-methyl-1H-pyrazol-5-yl)-1-phenylpyridazin-4(1H)-one

Participants

Reaction Conditions

Reaction Steps

To a suspension of 3-acetyl-5-methoxy-1-phenylpyridazin-4(1H)-one (6.0 g) in dimethylformamide dimethylacetal (49.33 mL) was added acetonitrile (18 mL) and the mixture was stirred at 90° C. for 4.5 hr. The reaction mixture was allowed to cool to room temperature, and concentrated under reduced pressure to dryness. The residue was dissolved in ethanol (42.3 mL). To the reaction mixture was added dropwise with stirring under ice-cooling a solution of methylhydrazine (2.26 g) in 10% trifluoroacetic acid-containing ethanol (84.58 mL). The mixture was stirred at the same temperature for 10 min, allowed to warm to room temperature, and stirred for 18 hr. The crystals precipitated in the reaction mixture was collected by filtration, washed successively with ethanol and diisopropyl ether, and dried to give the title compound (3.81 g) as pale-yellow crystals. Furthermore, the filtrate and the washing were combined, and concentrated under reduced pressure to dryness. The residue was purified by silica gel column chromatography (ethyl acetate/methanol) to give the title compound (0.84 g) as pale-yellow crystals.

Provenance & Evidence