Synthesis
Synthesis Example 1: 3,3',5,5'-Tetrabromo-2,2'-bithiophene was prepared by bromination from 2,2'-bithiophene. The procedure was as follows: 2,2'-bithiophene (30 mmol, 5 g) was dissolved in a solvent mixture of acetic acid (100 ml) and chloroform (75 ml) and subsequently cooled in an ice bath. A bromine solution was prepared by dissolving bromine (60.5 mmol, 9.65 g) in chloroform (50 ml). This bromine solution was added dropwise to the cooled 2,2'-bithiophene solution for about 40 minutes. Subsequently, the addition of the same amount of bromine solution was continued dropwise at room temperature for about 1 hour. The reaction mixture was stirred at room temperature for 12 hours and then circulated for 24 hours. After completion of the reaction, the solvent was removed by distillation under reduced pressure. The crude product was recrystallized from ethanol to give 15 g (30 mmol) of 3,3',5,5'-tetrabromo-2,2'-bithiophene in 100% yield. The product was analyzed by GC-MS and the calculated value (C8H2Br4S2 [M+]) was 482 and the measured value was 482.1H NMR (DMSO-d6) data: δ 7.5 (s, 2H).
References
[1] Journal of the American Chemical Society, 1993, vol. 115, # 25, p. 12214 - 12215
[2] Patent: US2010/240910, 2010, A1. Location in patent: Page/Page column 13-15
[3] Journal of the American Chemical Society, 2012, vol. 134, # 21, p. 8944 - 8957
[4] Heterocycles, 1991, vol. 32, # 9, p. 1805 - 1812
[5] Bulletin of the Chemical Society of Japan, 1991, vol. 64, # 8, p. 2566 - 2568
