Sodium Hydroxide → 3-(Difluoromethyl)-1-methyl-1H-pyrazole

Participants

Reaction Steps

3-Dichloromethyl-N-methylpyrazole (40.0 g; 0.21 mol; 84.8% pure according to GC analysis) comprising, as minor component, 5-dichloromethyl-N-methylpyrazole was stirred with triethylamine trishydrofluoride (199 g, 1.23 mol) at 160° C. under intrinsic pressure (<1 bar) for 1 h. The reaction mixture was vented and poured onto ice (500 g), made alkaline using aqueous sodium hydroxide solution and extracted three times with methyl tert-butyl ether (100 ml). The organic phases were combined, washed successively with hydrochloric acid (dilute, 100 ml) and a saturated aqueous NaCl solution (100 ml), dried over magnesium sulfate and freed from the solvent under reduced pressure. The residue obtained was 3-difluoromethyl-1-methylpyrazole (24.8 g, yield: 78%) in a purity of 85.4% (according to GC analysis) comprising, as minor component, 5-difluoromethyl-N-methylpyrazole.

Provenance & Evidence