Bromine → 4-Bromo-3-methyl-5-(trifluoromethyl)pyrazole

HRID 220454

Reaction equation

HRID 220454 reaction equation
[CH3:1][C:2]1[NH:6][N:5]=[C:4]([C:7]([F:10])([F:9])[F:8])[CH:3]=1.C([O-])(=O)C.[Na+].[Br:16]Br.S([O-])([O-])=O.[Na+].[Na+]>C(O)(=O)C.C(OCC)(=O)C>[Br:16][C:3]1[C:4]([C:7]([F:10])([F:9])[F:8])=[N:5][NH:6][C:2]=1[CH3:1]

Participants

7

Reactant 4

HCID 24408BromineHCID 24437Sodium SulfiteHCID 1390771H-Pyrazole, 3-methyl-5-(trifluoromethyl)-HCID 517045Sodium Acetate

Product 1

HCID 27364304-Bromo-3-methyl-5-(trifluoromethyl)pyrazoleYield 100%

Reagents, catalysts & solvents 2

HCID 176Acetic AcidSolventHCID 8857Ethyl AcetateSolvent

Conditions

Temperature
0 °C

Procedure

Dissolve 5-methyl-3-(trifluoromethyl)pyrazole (1.00 g, 6.66 mmol) in 60% aqueous acetic acid (13 mL). Add sodium acetate (0.819 g, 9.99 mmol) and cool to 0° C. Add bromine (1.17 g, 7.33 mmol) dropwise over 10 min. Stir at 0° C. for 3 hr, then at room temperature for 18 hr. Add ethyl acetate and saturated aqueous sodium sulfite solution. Separate organics and wash one time with saturated aqueous sodium bicarbonate solution followed by saturated aqueous sodium chloride. Dry (magnesium sulfate), filter and concentrate to give 4-bromo-5-methyl-3-trifluoromethyl-1H-pyrazole (1.50 g, 100%). GC-MS: m/z=229 [M+].

Workup

  1. waitat room temperature for 18 hr
  2. washSeparate organics and wash one time with saturated aqueous sodium bicarbonate solution
  3. dry with materialDry (magnesium sulfate)
  4. filtrationfilter
  5. concentrationconcentrate

Sources & evidence

ORD record
ord-33e599f9ee714cb982e2ab2c1ef6a0fd
Source dataset
uspto-grants-2012_06
Patent number
US08202873B2

Linked notes

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