反应详情

温度

50 °C

A mixture of 1-difluoromethyl-1H-pyrazole-3-carboxylic acid methyl ester (535 mg, 3 mmol) and N-chloro-succinimide (1.22 g, 9.1 mmol) in N,N-dimethylformamide (5 ml) was heated at 50° C. overnight. The reaction mixture was cooled, poured into water (20 ml), then extracted with ethyl acetate. The organic layer was separated, washed with water, dried over sodium sulphate, finally evaporated at reduced pressure. The yellowish crude material was purified by chromatography on silica gel using a 3:1-mixture of cyclohexane and ethyl acetate as the eluent. The 4-chloro-1-difluoromethyl-1H-pyrazole-3-carboxylic acid methyl ester was obtained as a white solid (540 mg, 84% of theory). MS (ISP): m/z=209.9 [M]+.

1. temperatureThe reaction mixture was cooled
2. extractionextracted with ethyl acetate
3. customThe organic layer was separated
4. washwashed with water
5. dry with materialdried over sodium sulphate
6. customfinally evaporated at reduced pressure
7. customThe yellowish crude material was purified by chromatography on silica gel using a 3