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

Temperature

90 °C

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.

1. temperatureto cool to room temperature
2. concentrationconcentrated under reduced pressure to dryness
3. dissolutionThe residue was dissolved in ethanol (42.3 mL)
4. additionTo the reaction mixture was added dropwise
5. stirringwith stirring under ice-
6. temperaturecooling a solution of methylhydrazine (2.26 g) in 10% trifluoroacetic acid-
7. additioncontaining ethanol (84.58 mL)
8. stirringThe mixture was stirred at the same temperature for 10 min
9. temperatureto warm to room temperature
10. stirringstirred for 18 hr
11. customThe crystals precipitated in the reaction mixture
12. filtrationwas collected by filtration
13. washwashed successively with ethanol and diisopropyl ether
14. customdried

ORD record

ord-53fc600d26884267b8a27ed83a636caf

Source dataset

uspto-grants-2014_11

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US08883788B2