Water → Ethyl (4-bromo-2,5-dimethyl-thiophen-3-yl)-oxo-acetate

HRID 591020Notes

Reaction equation

HRID 591020 reaction equation
[Cl-].[Al+3].[Cl-].[Cl-].[Br:5][C:6]1[CH:10]=[C:9]([CH3:11])[S:8][C:7]=1[CH3:12].Cl[C:14](=[O:20])[C:15]([O:17][CH2:18][CH3:19])=[O:16].O>ClCCl>[Br:5][C:6]1[C:10]([C:14](=[O:20])[C:15]([O:17][CH2:18][CH3:19])=[O:16])=[C:9]([CH3:11])[S:8][C:7]=1[CH3:12]

Participants

6

Reactant 4

HCID 962WaterHCID 20884Ethoxalyl chlorideHCID 6385853-Bromo-2,5-dimethylthiopheneHCID 6451240Aluminum(III) Chloride

Product 1

HCID 70818387Ethyl (4-bromo-2,5-dimethyl-thiophen-3-yl)-oxo-acetateYield 39.3%

Reagents, catalysts & solvents 1

HCID 6344DichloromethaneSolvent

Procedure

Under a nitrogen atmosphere, aluminium chloride (1.46 g, 11 mmol) was added per portions at 0° C. to a solution of 3-bromo-2,5-dimethylthiophene (17b) (1.05 g, 5.49 mmol) and ethyl chlorooxoacetate (614 μL, 5.5 mmol) in dichloromethane (12 mL). After 2 hours of vigorous stirring, the reaction mixture was slowly hydrolyzed at 0° C. with water. The organic layer was separated, washed with hydrochloric acid aqueous solution 1N, brine, dried over sodium sulfate, filtered and evaporated under reduced pressure. The residue was purified by flash chromatography on silica gel (cyclohexane/ethyl acetate 95/5)) to afford the desired keto-ester (17c) as a orange solid (630 mg, 2.16 mmol, 39%).

Workup

  1. customThe organic layer was separated
  2. washwashed with hydrochloric acid aqueous solution 1N, brine
  3. dry with materialdried over sodium sulfate
  4. filtrationfiltered
  5. customevaporated under reduced pressure
  6. customThe residue was purified by flash chromatography on silica gel (cyclohexane/ethyl acetate 95/5))

Sources & evidence

ORD record
ord-2143aba0159240bdbf63960d01126530
Source dataset
uspto-grants-2016_01
Patent number
US09238026B2

Reaction notes

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