2,5-dibromo-3,4-dimethylthieno[2,3-b]thiophene → HCID 23070261, compound

HRID 351297Notes

Reaction equation

HRID 351297 reaction equation
Br[C:2]1[S:3][CH:4]=[CH:5][C:6]=1[CH2:7][CH2:8][CH2:9][CH2:10][CH2:11][CH2:12][CH2:13][CH3:14].Br[C:16]1[S:25][C:19]2[S:20][C:21](Br)=[C:22]([CH3:23])[C:18]=2[C:17]=1[CH3:26]>C1COCC1.[Zn]>[CH2:7]([C:6]1[CH:5]=[CH:4][S:3][C:2]=1[C:16]1[S:25][C:19]2[S:20][C:21]([C:2]3[S:3][CH:4]=[CH:5][C:6]=3[CH2:7][CH2:8][CH2:9][CH2:10][CH2:11][CH2:12][CH2:13][CH3:14])=[C:22]([CH3:23])[C:18]=2[C:17]=1[CH3:26])[CH2:8][CH2:9][CH2:10][CH2:11][CH2:12][CH2:13][CH3:14]

Participants

5

Reactant 2

HCID 28201622,5-dibromo-3,4-dimethylthieno[2,3-b]thiopheneHCID 107548542-Bromo-3-n-octylthiophene

Product 1

HCID 23070261HCID 23070261, compoundYield 72%

Reagents, catalysts & solvents 2

HCID 23994ZincCatalystHCID 8028TetrahydrofuranSolvent

Procedure

To a solution of 2-bromo-3-octylthiophene (4.0 g, 14.5 mmol) in dry THF (20 ml) under nitrogen was added a solution of Rieke zinc (Aldrich, 1.1 g 20 ml of THF, 17 mmol) at −78° C. The solution was allowed to warm to RT and stirred for 16 h. Stirring was stopped and the solution allowed to settle for 2 h. The resultant solution was transferred by cannula into a flask containing 2,5-dibromo-3,4-dimethylthieno[2,3-b]thiophene (1.28 g, 3.9 mmol), degassed THF (50 ml) and [1,1′-bis(diphenylphosphino)ferrocene]palladium(II) chloride (64 mg, 2 mol %) at 0° C. The reaction was warmed to RT over 30 min, and then refluxed for 24 h. The reaction was cooled and quenched with 5% HCL. The resultant mixture was extracted with ethyl acetate (3×50 ml), and the combined organics were washed with brine, dried (Na2SO4), filtered and concentrated under reduced pressure. The crude product was purified by flash chromatography over silica (eluent: petrol), followed by reverse phase chromatography (eluent: CH3CN/THF 2:1) to afford the product as a colourless oil (1.56 g, 72%). M/Z 556 (M+). Found C, 69.1%, H, 7.6%. Calc. for C32H44S4 C, 69.0; H 8.0. NMR gave the expected signals.

Workup

  1. stirringStirring
  2. waitto settle for 2 h
  3. customdegassed THF (50 ml) and [1,1′-bis(diphenylphosphino)ferrocene]palladium(II) chloride (64 mg, 2 mol %) at 0° C
  4. temperatureThe reaction was warmed to RT over 30 min
  5. temperaturerefluxed for 24 h
  6. temperatureThe reaction was cooled
  7. customquenched with 5% HCL
  8. extractionThe resultant mixture was extracted with ethyl acetate (3×50 ml)
  9. washthe combined organics were washed with brine
  10. dry with materialdried (Na2SO4)
  11. filtrationfiltered
  12. concentrationconcentrated under reduced pressure
  13. customThe crude product was purified by flash chromatography over silica (eluent: petrol)

Sources & evidence

ORD record
ord-74028ea77fb448cb9040874c0756ffb5
Source dataset
uspto-grants-2007_02
Patent number
US07183418B2

Reaction notes

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