Bromine → 4-Bromo-1,5-Dimethyl-3-(Trifluoromethyl)-1H-Pyrazole

HRID 895683Notes

Reaction equation

HRID 895683 reaction equation
[Br:1]Br.[CH3:3][N:4]1[C:8]([CH3:9])=[CH:7][C:6]([C:10]([F:13])([F:12])[F:11])=[N:5]1.C([O-])(=O)C.[Na+]>>[Br:1][C:7]1[C:6]([C:10]([F:12])([F:11])[F:13])=[N:5][N:4]([CH3:3])[C:8]=1[CH3:9]

Participants

4

Reactant 3

HCID 24408BromineHCID 517045Sodium AcetateHCID 127475251,5-Dimethyl-3-(trifluoromethyl)pyrazole

Product 1

HCID 118590454-Bromo-1,5-Dimethyl-3-(Trifluoromethyl)-1H-PyrazoleYield 80%

Procedure

A total of 61.9 g (388 mmol) of bromine are added dropwise at 0° C. within 2.5 h to a suspension of 60 g (366 mmol) of 1,5-dimethyl-3-trifluoromethyl-1H-pyrazole and 30.0 g (366 mmol) of anhydrous sodium acetate in 600 ml of CHC13. On completion of addition, the mixture is allowed to come to 20° C. and is stirred for a further 4 d. After the end of the reaction, the mixture is washed with 30% NaHCO3 solution, the aqueous phase is further extracted twice using 200 ml of CHC13 each time and the combined organic phases are dried over MgSO4 and concentrated. Recystallization results in 70.6 g (291 mmol, 80%) of 4-bromo-1,5-dimethyl-3-(trifluoromethyl)-1H-pyrazole as a bright yellow solid.

Workup

  1. additionOn completion of addition
  2. customto come to 20° C.
  3. customAfter the end of the reaction
  4. washthe mixture is washed with 30% NaHCO3 solution
  5. extractionthe aqueous phase is further extracted twice
  6. dry with materialthe combined organic phases are dried over MgSO4
  7. concentrationconcentrated

Sources & evidence

ORD record
ord-4b029bc98cdd45568357106d5a1f8ccb
Source dataset
uspto-grants-2005_07
Patent number
US06916839B2

Reaction notes

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