p-Toluenesulfonic acid → Ethyl (2-bromo-4,5-difluorobenzoyl)acetate
Reaction equation
[Br:1][C:2]1[CH:20]=[C:19]([F:21])[C:18]([F:22])=[CH:17][C:3]=1[C:4]([CH:6](C(OCC)=O)[C:7]([O:9][CH2:10][CH3:11])=[O:8])=[O:5].C1(C)C=CC(S(O)(=O)=O)=CC=1>O>[Br:1][C:2]1[CH:20]=[C:19]([F:21])[C:18]([F:22])=[CH:17][C:3]=1[C:4]([CH2:6][C:7]([O:9][CH2:10][CH3:11])=[O:8])=[O:5]Participants
4
Reactant 2
Product 1
Reagents, catalysts & solvents 1
Procedure
To a solution of diethyl (2-bromo-4,5-difluorobenzoyl)malonate (75.6 g) in water (100 ml) is added p-toluenesulfonic acid (0.3 g), and the mixture is refluxed for 3 hours. After cooling, the reaction mixture is extracted with dichloromethane. The dichloromethane layer is washed with saturated aqueous sodium chloride solution and dried over magnesium sulfate. After distilling off the solvent under reduced pressure, the residue is distilled to give ethyl (2-bromo-4,5-difluorobenzoyl)acetate (52.0 g), b.p. 105°-115° C. (0.15 mmHg).