Thionyl Chloride → 5-fluoro-1-methyl-3-difluoromethyl-1H-pyrazole-4-carbonyl chloride

Participants

Reaction Conditions

Reaction Steps

A solution of 22.3 g (100 mmol) of ethyl 5-fluoro-1-methyl-3-difluoromethyl-1H-pyrazole-4-carboxylate in 100 ml of toluene and 50 ml of 10% NaOH are stirred at AT for 3 hours. The aqueous phase is separated and adjusted to pH 5 with HCl. After extracting the product with chlorobenzene and azeotropically drying the organic phase, 23.8 g (200 mmol) of SOCl2 are added to the solution and the mixture is heated at 80° C. for 2 hours. After evaporating the reaction mixture, 20.1 g of the product are obtained as an oil with a purity (GC) of 98%.

Provenance & Evidence