Sodium Hydroxide → 4-Bromo-3-(difluoromethyl)-1-methyl-1H-pyrazole

Participants

Reaction Steps

At 160° C., 4-bromo-3-dichloromethyl-1-methylpyrazole (3.0 g; 0.01 mol; 90% pure according to GC analysis) was stirred with triethylamine trishydrofluoride (25 g, 0.16 mol) under autogenous pressure (<1 bar) for 1 h. After venting, the reaction mixture is added to ice (200 g), made alkaline with aqueous sodium hydroxide solution and extracted three times with methyl tert-butyl ether (100 ml). The combined organic phases were washed successively with dilute hydrochloric acid (100 ml) and a saturated aqueous NaCl solution (100 ml) and dried over magnesium sulfate, and the solvent was removed under reduced pressure. 4-Bromo-3-difluoromethyl-1-methylpyrazole was isolated in a purity of 81.3% (GC analysis) with a yield of 2.0 g (70%).

Provenance & Evidence