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

Participants

Reaction Conditions

Reaction Steps

Zn powder (31.7 g, 0.485 mol) was added in portions to a vigorously stirred refluxing mixture of bithiophene (1) (77.9 g, 0.162 mol) in 400 mL of ethanol containing 40 mL of water, 100 mL of glacial acetic acid, and 8 mL of 3 M HCl (aq). After refluxing for 2 h, the mixture was filtered hot and upon cooling to 0° C., yellow crystals were collected by filtration. The crystals were dissolved in diethyl ether, washed three times with 200 mL of water, once with 100 mL of brine, and dried over anhydrous MgSO4. The organic solution was filtered and the solvent was removed by evaporation to give 49.4 g (94% yield) of a light yellow powder. Anal. Calcd. for C8H4Br2S2: C, 29.65; H, 1.24. Found: C, 29.59; H, 1.14; 1H NMR (CDCl3): 7.41 (d, J=5.3 Hz, 2H), 7.09 (d, J=5.3 Hz, 2H) ppm.

Provenance & Evidence