反应详情

To a solution of acetonitrile (4.8 g) in THF (150 mL) was added n-BuLi (67 mmol) at −78° C. Further, methyl butanoate (10 g) was added and the mixture was stirred for one hour. After acidification with hydrochloric acid, the mixture was extracted with ethyl acetate. The solvent was evaporated under reduced pressure and the residue was purified by silica gel column chromatography (eluent:hexane-ethyl acetate (10:1)) to give 1-cyanopentan-2-one (5.5 g) as a colorless oil. A solution of 2-chlorobenzaldehyde (1.9 g), 3-aminopyrazole (1.0 g) and 1-cyanopentan-2-one (1.6 g) in acetonitrile (20 mL) was heated under reflux overnight. The reaction mixture was cooled to room temperature, and the precipitated crystals were collected by filtration to give the title compound (1.3 g) as colorless crystals.

1. temperatureunder reflux overnight
2. filtrationthe precipitated crystals were collected by filtration