反应详情

1.5 g (0.0084 mol) of 3-(4-chlorophenyl)-1H-pyrazole, prepared in the above example (19), are dissolved, at room temperature and with stirring, in 25 ml of acetic acid. 1.6 g (0.01 mol) of bromine are then run in dropwise while maintaining the temperature below 30° C. Stirring is maintained for 30 hours 30 min and then the reaction mixture is poured into water. The precipitate is filtered and washed with water and heptane. 2.1 g (0.0084 mol) (yield: 100%; melting point: 143° C.) of 4-bromo-3-(4-chlorophenyl)-1H-pyrazole are obtained.

1. dissolutionare dissolved, at room temperature
2. temperaturewhile maintaining the temperature below 30° C
3. temperatureis maintained for 30 hours 30 min
4. filtrationThe precipitate is filtered
5. washwashed with water and heptane