Bromine → 4-Bromo-3-(difluoromethyl)-1-methyl-1H-pyrazole
Reaction equation
[Br:1]Br.[F:3][CH:4]([F:11])[C:5]1[CH:9]=[CH:8][N:7]([CH3:10])[N:6]=1.S([O-])([O-])(=O)=S.[Na+].[Na+]>C(Cl)Cl>[Br:1][C:9]1[C:5]([CH:4]([F:11])[F:3])=[N:6][N:7]([CH3:10])[CH:8]=1Participants
5
Reactant 3
Product 1
Reagents, catalysts & solvents 1
Conditions
- Temperature
- 25 °C
Procedure
At 25° C., bromine (Br2, 3 g) was added dropwise to a solution of 3-difluoromethyl-N-methylpyrazole (2.0 g) in methylene chloride (80 ml). The reaction mixture was stirred for a total of 22 h at 25° C., and aqueous sodium thiosulfate solution (0.1 M, 210 ml) was then added. After phase separation, the organic phase was freed from the solvent under reduced pressure (40° C./5 mbar). Part of the residue obtained (2.4 g of 2.8 g) was separated by column chromatography (SiO2, ethyl acetate/cyclohexane 1:6). 4-bromo-3-difluoromethyl-1-methylpyrazole was isolated in an amount of 1.4 g.
Workup
- customAfter phase separation
- customwas freed from the solvent under reduced pressure (40° C./5 mbar)
- customPart of the residue obtained (2.4 g of 2.8 g)
- customwas separated by column chromatography (SiO2, ethyl acetate/cyclohexane 1:6)
Sources & evidence
- ORD record
- ord-66cb5cd437594d278f714858f78f4752
- Source dataset
- uspto-grants-2012_04
- Patent number
- US08153820B2
Reaction notes
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