Acetic Acid → 3,3'-Dibromo-2,2'-bithiophene

Participants

Reaction Steps

3,3′,5,5′-Tetrabromo-2,2′-bithiophene 10 (12.5 g, 25.9 mmol) was added in portions within 0.5 h to a refluxing dispersion of Zn powder (6.5 g, 0.1 mol) in 130 mL of ethanol containing 13 mL of water, 31 mL of glacial acetic acid, and 2.6 mL of 3 M HCl. After heating under reflux for two additional hours and then cooling to room temperature, the mixture was filtered and washed three times with ethanol, and the filtrate was collected. The solvent was then removed by evaporation, and 60 mL of H2O was added. The mixture was then extracted with diethyl ether, and the combined extracts were washed with water, dried over anhydrous MgSO4, and filtered. The solvent was removed by evaporation, and the crude product was recrystallized from hexane to give colorless crystals (7.6 g, yield 90%). 1H NMR (CDCl3): 7.41 (d, J=5.3 Hz, 2H), 7.09 (d, J=5.3 Hz, 2H) ppm; 13C NMR (CDCl3): δ 112.84, 127.73, 129.07, 131.01 ppm.

Provenance & Evidence