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

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Reaction Steps

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.

Provenance & Evidence