Triphenylphosphine → 1,4-dimethyl-5-(2,2-difluoroethoxy)-3-trifluoromethyl-1H-pyrazole

Participants

Reaction Steps

To a solution of 9.0 g (50.0 mmol) of 1,4-dimethyl-5-hydroxy-3-trifluoromethyl-1H-pyrazole in 50 ml of tetrahydrofuran were added 14.4 g (55.0 mmol) of triphenylphosphine and 4.5 g (55.0 mmol) of 2,2-difluoroethanol at room temperature, followed by stirring. Furthermore, 12.3 g (60.0 mmol) of diisopropyl azodicarboxylate was added thereto under ice-cooling, followed by stirring at room temperature overnight. 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 purified by silica gel column chromatography to obtain 6.8 g (yield: 55.7%) of 1,4-dimethyl-5-(2,2-difluoroethoxy)-3-trifluoromethyl-1H-pyrazole as a pale yellow liquid.

Provenance & Evidence