Hydrogen Bromide → 4-Bromo-2,5-difluoro-3-methylbenzoic acid

HRID 1584812Notes

Reaction equation

HRID 1584812 reaction equation
N[C:2]1[C:10]([F:11])=[CH:9][C:5]([C:6]([OH:8])=[O:7])=[C:4]([F:12])[C:3]=1[CH3:13].N([O-])=O.[Na+].C1(C)C=CC=CC=1.CCCCCC.[BrH:31]>O>[Br:31][C:2]1[C:10]([F:11])=[CH:9][C:5]([C:6]([OH:8])=[O:7])=[C:4]([F:12])[C:3]=1[CH3:13]

Participants

7

Reactant 5

HCID 260Hydrogen BromideHCID 1140TolueneHCID 8058HexaneHCID 21220450HCID 21220450, compoundHCID 23668193Sodium Nitrite

Product 1

HCID 212202454-Bromo-2,5-difluoro-3-methylbenzoic acid

Reagents, catalysts & solvents 1

HCID 962WaterSolvent

Procedure

In 658 ml of 4.7% hydrobromic acid was suspended 26.3 g of 4-amino-2,5-difluoro-3-methylbenzoic acid, and 161 g of cupric bromide was added to the suspension. To this suspension was dropwise added a solution of 16.5 g of sodium nitrite in 165 ml of water over one hour with ice-cooling, and the resulting mixture was stirred for one hour at the same temperature and then at room temperature for two hours. To the reaction mixture was added 700 ml of toluene and the organic layer formed was separated, washed with 100 ml of conc. hydrochloric acid and then dried over anhydrous magnesium sulfate. The solvent was then removed by distillation under reduced pressure. To the residue obtained was added n-hexane and the resulting crystals were collected by filtration to obtain 29.5 g of colorless, crystalline 4-bromo-2,5-difluoro-3-methylbenzoic acid.

Workup

  1. additionwas added to the suspension
  2. temperaturecooling
  3. waitat room temperature for two hours
  4. customthe organic layer formed
  5. customwas separated
  6. washwashed with 100 ml of conc. hydrochloric acid
  7. dry with materialdried over anhydrous magnesium sulfate
  8. customThe solvent was then removed by distillation under reduced pressure
  9. customTo the residue obtained
  10. filtrationthe resulting crystals were collected by filtration

Sources & evidence

ORD record
ord-a5342e40cba54d418135a58fcbd0d085
Source dataset
uspto-grants-1999_08
Patent number
US05935952

Reaction notes

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