反应详情

温度

120 °C

100 g (0.270 mol) of 5-amino-4-ethoxycarbonyl-1-(2,3,5,6-tetrafluoro-4-trifluoromethyl-phenyl)-pyrazole are suspended in 250 ml of 50 percent strength aqueous sulphuric acid and the suspension is warmed to 120° C. in the course of 2 hours; the more highly volatile constituents are thereby distilled off over a bridge. The mixture is kept at 115° C.-120° C. for a further 3 hours and is cooled and diluted with 400 ml of water, the pH is brought to 2 with dilute aqueous sodium hydroxide solution and the precipitate formed is filtered off with suction. It is washed neutral with water and dried in vacuo. 77.3 g (96% of theory) of 5-amino-1-(2,3,5,6-tetrafluoro-4-trifluoromethyl-phenyl)-pyrazole of melting point 103° C.-104° C. are obtained.

1. distillationthe more highly volatile constituents are thereby distilled off over a bridge
2. temperatureis cooled
3. additiondiluted with 400 ml of water
4. customthe precipitate formed
5. filtrationis filtered off with suction
6. washIt is washed neutral with water
7. customdried in vacuo