Synthesis
The general procedure for the synthesis of 1,6-dibromopyrene and 1,8-dibromopyrene from pyrene was as follows: first, 58 g (0.287 mol) of pyrene was dissolved in 1750 ml of chloroform. Subsequently, 31 ml (0.609 mol) of bromine in 250 ml of chloroform was slowly added dropwise at room temperature and protected from light. After the dropwise addition was completed, the reaction mixture was heated under reflux conditions for 4 hours. After completion of the reaction, the mixture was cooled and the precipitated solid product was collected by diafiltration. The solid was washed with ethanol to remove impurities and then dried. Finally, the solid obtained was recrystallized from chloroform three times to improve the purity of the product. Ultimately, 73.4 g (0.201 mol) of 1,6-dibromopyrene was obtained in 71.1% yield of the theoretical value, as well as 20.6 g (0.06 mol) of 1,8-dibromopyrene in 20% yield of the theoretical value.
References
[1] Dyes and Pigments, 2016, vol. 130, p. 106 - 115
[2] Journal of Molecular Structure, 2017, vol. 1127, p. 237 - 246
[3] Patent: WO2013/185871, 2013, A1. Location in patent: Page/Page column 24
[4] Mendeleev Communications, 2016, vol. 26, # 5, p. 437 - 439
[5] Dyes and Pigments, 2018, vol. 158, p. 42 - 49
