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

Participants

Reaction Steps

3,3′,5,5′-Tetrabromo-2,2′-bithiophene, 10 (15 g, 31.1 mmol) was added in portion within 0.5 h to a refluxing dispersion of zinc powder (7.8 g, 0.12 mol) in 150 mL of ethanol containing 15 mL of water, 72 mL of glacial acetic acid, and 3.1 mL of 3 M HCl. After refluxing for an additional 2 h 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 dichloromethane (3×100 mL), and the combined extract was washed with water, dried over anhydrous MgSO4, and filtered. The solvent was removed by evaporation, and the crude product was crystallized from hexane to give colorless crystals of product 9.2 g, 92% yield. 1H NMR (400 MHz, CDCl3, δ) 7.43 (d, J=5.4 Hz, 2H), 7.09 (d, J=5.4 Hz, 2H). 13C NMR (100 MHz, CDCl3, δ) 130.8, 128.8, 127.5, 112.6. MS (FAB): m/z 324.0 (M+).

Provenance & Evidence