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

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%).

1. extractionextracted three times with methyl tert-butyl ether (100 ml)
2. washThe combined organic phases were washed successively with dilute hydrochloric acid (100 ml)
3. dry with materiala saturated aqueous NaCl solution (100 ml) and dried over magnesium sulfate
4. customthe solvent was removed under reduced pressure

ORD record

ord-303c5ec6de4548c18be6ce1dbffcb892

Source dataset

uspto-grants-2012_04

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US08153820B2