Synthesis
General procedure for the synthesis of 9,9-dihexyl-2,7-dibromofluorene from 2,7-dibromofluorene and 1-bromohexane: 2,7-dibromofluorene (1.5 g), and triethylbenzylammonium chloride (0.009 g) were suspended in 30 mL of dimethylsulfoxide in a triple-necked flask. 1.5 mL of 50 wt% aqueous sodium hydroxide solution was slowly added dropwise and the reaction was carried out for 30 min followed by the addition of 1.59 g of 1-bromohexane dropwise. The reaction mixture was stirred at room temperature for 3 h. After completion of the reaction, it was extracted with ether. The organic phase was sequentially washed with saturated brine and dried over anhydrous magnesium sulfate. The solvent was removed by distillation under reduced pressure and the resulting crude product was recrystallized from aqueous ethanol to give orange needle-like crystals of 2,7-dibromo-9,9-dihexylfluorene (1.96 g) in 86% yield.
References
[1] Journal of Organic Chemistry, 2010, vol. 75, # 8, p. 2714 - 2717
[2] Macromolecules, 2003, vol. 36, # 19, p. 6995 - 7003
[3] Chemical Communications, 2008, # 32, p. 3765 - 3767
[4] Macromolecules, 2003, vol. 36, # 19, p. 6970 - 6975
[5] Tetrahedron Letters, 2007, vol. 48, # 1, p. 89 - 93
