Boron tribromide → 6-Hydroxy-2-methylbenzo[b]thiophene-3-carboxylic acid

HRID 130659Notes

Reaction equation

HRID 130659 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]=1

Participants

4

Reactant 2

HCID 25134Boron tribromideHCID 221435646-Methoxy-2-methylbenzo[b]thiophene-3-carboxylic acid

Product 1

HCID 221435426-Hydroxy-2-methylbenzo[b]thiophene-3-carboxylic acidYield 44.8%

Reagents, catalysts & solvents 1

HCID 6344DichloromethaneSolvent

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.

Workup

  1. customwas removed
  2. stirringThe reaction was stirred at room temperature overnight
  3. customThe reaction was quenched with water at 0° C
  4. extractionThe mixture was extracted with EtOAc
  5. filtrationInsoluble was collected by filtration

Sources & evidence

ORD record
ord-bbbfd15afbd4426480b5be6a17142947
Source dataset
uspto-grants-2008_06
Patent number
US07381824B2

Reaction notes

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