Toluene → Ethyl 3-difluoromethyl-1-methyl-4-pyrazole carboxylate

Participants

Reaction Conditions

Reaction Steps

The toluene solution of crude ethyl 3-difluoromethylpyrazole-4-carboxylate was stirred and cooled to 20° C. Water (260 ml), tetramethylammonium chloride (10% aqueous solution, 15.0 g), and 25% NaOH solution (36-60 g) were added in sequence. Dimethyl sulphate (99.5%, 94.5 g, 0.75 mol) and additional 25% NaOH were fed simultaneously over 2 hours at 20° C. while maintaining the pH between 10.5 and 12.0. After 2 hours post reaction, the bottom aqueous phase was separated off.

Provenance & Evidence