Sulfuric Acid → 4-Chloro-3-(2,4-dichloro-5-formylphenyl)-5-difluoromethoxy-1-methyl-1H-pyrazole

Participants

Reaction Conditions

Reaction Steps

45.5 g (91 mmol) of 3-(5-dibromomethyl-2,4-dichlorophenyl)-4-chloro-5-difluoromethoxy-1-methyl-1H-pyrazole were added, a little at a time, to 65 ml of concentrated sulfuric acid at 85° C., during which process the mixture was heated slowly to 95° C. The reaction mixture was subsequently stirred at 103° C. for a further 5 minutes, whereupon it was stirred into 600 ml of ice-water. The product was extracted using dichloromethane. The organic phase was washed using saturated sodium chloride solution, dried over magnesium sulfate, filtered and finally concentrated. The crude product was purified by dissolving in hexane/ethyl acetate (1:1) and filtering the solution through a silica gel bed. Yield after concentration: 20 g.

Provenance & Evidence