Synthesis
General procedure for the synthesis of 5-bromo-2,2-bithiophene from bithiophene: 3 g (18 mmol) of 2,2'-bithiophene and 50 mL of N,N-dimethylformamide (DMF) were placed in a 250 mL two-necked round-bottomed flask and dissolved by stirring. A solution of 3.2 g (18 mmol) of N-bromosuccinimide (NBS) dissolved in 10 mL of DMF was added slowly and dropwise under cooling in an ice bath. After completion of the reaction, the reaction mixture was extracted with dichloromethane (DCM) and the organic phase was collected. Purification by recrystallization from methanol (MeOH) gave 2.5 g of light yellow solid product in 56% yield. The resulting intermediate (1) was characterized by nuclear magnetic resonance hydrogen spectroscopy (1H NMR, CDCl3, 400 MHz) with the following chemical shifts: δ= 6.91 (1H, d), 6.96 (1H, d), 7.00 (1H, dd), 7.22 (1H).
References
[1] Patent: US6342610, 2002, B2. Location in patent: Page column 58
[2] ACS Catalysis, 2016, vol. 6, # 2, p. 1113 - 1121
[3] RSC Advances, 2017, vol. 7, # 89, p. 56586 - 56593
[4] Chemistry of Materials, 2010, vol. 22, # 7, p. 2325 - 2332
[5] Journal of Organic Chemistry, 1996, vol. 61, # 20, p. 6906 - 6921
