Water → 5-(Difluoromethoxy)-1,4-dimethyl-3-(trifluoromethyl)-1H-pyrazole

Participants

Reaction Steps

Into 78.6 g (436.4 mmol) of 1,4-dimethyl-5-hydroxy-3-trifluoromethyl-1H-pyrazole in 500 ml of 2-propanol was added 153.1 g (2728.6 mmol) of powdery potassium hydroxide at room temperature, followed by stirring. Furthermore, an excess amount of chlorodifluoromethane was introduced into the reaction solution under stirring. Thereafter, the reaction temperature once rose to 70° C. by exothermic heat and then returned to room temperature after 2 hours. After the completion of the reaction was confirmed, the reaction solution was poured into water and extracted with ethyl acetate. The resulting organic layer was washed with water and saline, successively, and then dried over anhydrous magnesium sulfate. The solvent was removed by evaporation under reduced pressure and the residue was distilled to obtain 88.9 g (yield: 88.5%) of 5-difluoromethoxy-1,4-dimethyl-3-trifluoromethyl-1H-pyrazole as a colorless transparent liquid.

Provenance & Evidence