Sulfuric Acid → HCID 13913427, compound

Participants

Reaction Steps

250 g (0.71 mol) of 5-amino-4-ethoxycarbonyl-1-(2-chloro-6-fluoro-4-trifluoromethylphenyl)-pyrazole are heated in 650 ml of 50% strength aqueous sulphuric acid at 120° C. for 2 hours, during which the volatile constituents distil off. The mixture is heated at 115° C. to 120° C. for a further 5 hours and then cooled, 3 l of ice-water are added, the pH is adjusted to 8 to 9 using aqueous sodium hydroxide solution, and the precipitate formed is filtered off, washed with water and dried in vacuo at 50° C. 163 g (82% of theory) of 5-amino-1-(2-chloro-6-fluoro-4-trifluoromethylphenyl)-pyrazole of melting point 87°-90° C. are obtained.

Provenance & Evidence