2-Acetylthiophene → 2-Bromo-1-(thiophen-2-yl)ethan-1-one

HRID 2298576Notes

Reaction equation

HRID 2298576 reaction equation
[C:1]([C:4]1[S:5][CH:6]=[CH:7][CH:8]=1)(=[O:3])[CH3:2].[Br:9]Br>C(Cl)(Cl)Cl.Br.CC(O)=O>[Br:9][CH2:2][C:1]([C:4]1[S:5][CH:6]=[CH:7][CH:8]=1)=[O:3]

Participants

5

Reactant 2

HCID 69202-AcetylthiopheneHCID 24408Bromine

Product 1

HCID 27763722-Bromo-1-(thiophen-2-yl)ethan-1-oneYield 37%

Reagents, catalysts & solvents 2

HCID 21893785Acetic Acid Mixture with Hydrobromic AcidCatalystHCID 6212ChloroformSolvent

Procedure

To a solution of 500 mg (3.96 mmol) of 2-acetyl thiophene (Aldrich Chemical Co.) dissolved in 20 mL of CHCl3, was added 1 drop of 30% HBr/CH3COOH (Aldrich Chemical Co.) followed by 3.96 mmol (633 mg; 204 μL) of bromine (Aldrich Chemical Co.) added dropwise over 30 min. The reaction was allowed to stir for 1 h. The solution was concentrated to an oil and dried in vacuo. The crude product was purified on 1 mm silica prep plates eluting with neat CH2Cl2 to obtain 300 mg (37% yield) of 2-bromo-1-(2-thienyl)ethan-1-one. 1H-NMR (CDCl3; 300 MHz) δ 7.8 (m, 2H), 7.18 (m, 1H), 4.37 (s, 2H).

Workup

  1. additionadded dropwise over 30 min
  2. concentrationThe solution was concentrated to an oil
  3. customdried in vacuo
  4. customThe crude product was purified on 1 mm silica
  5. washeluting with neat CH2Cl2

Sources & evidence

ORD record
ord-c4dec4485dcc482c86f7fd771b3fd833
Source dataset
uspto-grants-2002_12
Patent number
US06492403B1

Reaction notes

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