Synthesis
General procedure for the synthesis of 2,8-dibromodibenzofuran from dibenzofuran:
1a) Synthesis of 2,8-dibromodibenzofuran: A solution of bromine (92.6 g, 0.58 mol) in acetic acid (54 g) was added slowly and dropwise at 75 °C to a solution of dibenzofuran (23.2 g, 0.14 mol) in acetic acid (232 g). The reaction mixture was stirred continuously at 75°C for 3 hours. Upon completion of the reaction, the mixture was cooled to room temperature and slowly poured into deionized water. The precipitated orange solid was washed sequentially with aqueous sodium thiosulfate and deionized water. The crude product was purified by recrystallization from n-hexane to give a white solid product in 38% yield with a melting point of 226 °C. The structure of the product was confirmed by 1H-NMR (CDCl3, ppm): 7.65 (d, 2H), 7.59 (dd, 2H), 8.03 (d, 2H).
References
[1] Organic Letters, 2010, vol. 12, # 15, p. 3438 - 3441
[2] New Journal of Chemistry, 2015, vol. 39, # 3, p. 2096 - 2105
[3] Patent: WO2016/172255, 2016, A1. Location in patent: Page/Page column 101; 102
[4] Patent: KR101638767, 2016, B1. Location in patent: Paragraph 0117-0120
[5] Patent: EP2711363, 2014, A1. Location in patent: Paragraph 0252; 0253; 0254
