Ammonium Chloride → ethyl 3-[cyclopropyl(hydroxy)methyl]-1-methyl-4-(trifluoromethyl)-1H-pyrazole-5-carboxylate

Participants

Reaction Steps

A solution of 1.82 g (7.28 mmol) of ethyl 3-formyl-1-methyl-4-(trifluoromethyl)-1H-pyrazole-5-carboxylate in 80 ml of tetrahydrofuran is admixed under argon at −78° C. with 17.5 ml (8.73 mmol) of 0.5M cyclopropylmagnesium bromide solution in tetrahydrofuran, and stirred for 30 minutes at this temperature and then overnight at room temperature. The reaction solution is admixed with saturated ammonium chloride solution and extracted with ethyl acetate, and the organic phase is dried over sodium sulphate and concentrated by evaporation on a rotary evaporator. Chromatographic purification on silica gel gives 0.67 g of ethyl 3-[cyclopropyl(hydroxy)methyl]-1-methyl-4-(trifluoromethyl)-1H-pyrazole-5-carboxylate (31%).

Provenance & Evidence