Boron tribromide → 6-Hydroxy-2-methylbenzo[b]thiophene-3-carboxylic acid
Reaction equation
C[O:2][C:3]1[CH:15]=[CH:14][C:6]2[C:7]([C:11]([OH:13])=[O:12])=[C:8]([CH3:10])[S:9][C:5]=2[CH:4]=1.B(Br)(Br)Br>C(Cl)Cl>[OH:2][C:3]1[CH:15]=[CH:14][C:6]2[C:7]([C:11]([OH:13])=[O:12])=[C:8]([CH3:10])[S:9][C:5]=2[CH:4]=1Participants
4
Reactant 2
Product 1
Reagents, catalysts & solvents 1
Procedure
To a solution of 6-methoxy-2-methyl-1-benzothiophene-3-carboxylic acid 48-A (5 g, 22.5 mmol) in CH2Cl2 (50 ml) was added BBr3 (33 ml, 1M CH2Cl2 solution) at −78° C. After being stirred for 1 hour the cooling bath was removed. The reaction was stirred at room temperature overnight. The reaction was quenched with water at 0° C. The mixture was extracted with EtOAc. Insoluble was collected by filtration to yield 2.1 g of 6-hydroxy-2-methyl-1-benzothiophene-3-carboxylic acid (B). The organic layer was washed with brine, dried (MgSO4) and concentrated to give 2.7 g of 48-B.