Synthesis
Example 1 Synthesis of 2-iodofluorene: 90 mL of glacial acetic acid and 90 mL of water were added to a 300 mL four-necked flask, followed by the addition of 41.6 g (0.25 mole) of fluorene. Under vigorous stirring, 12.7 g (0.10 mol) of iodine, 1.93 g (0.018 mol) of sodium chlorate and 4.5 mL of concentrated sulfuric acid were added sequentially. The reaction mixture was refluxed at 85 to 90 °C for 30 min, followed by warming to 95 to 100 °C to continue refluxing for 30 min. Upon completion of the reaction, the reaction mixture was extracted with 55 mL of toluene. The organic layer was washed sequentially with 5% aqueous sodium thiosulfate solution and 50 mL of 20% brine solution. 216 mL of methanol was added to the organic layer and the mixture was crystallized at an internal temperature of 25 to 30 °C for 2 h. The crystals were collected by filtration. The crude product was washed with 76 mL of methanol, and 24.8 g (yield: 84.8%) of 2-iodofluorene was obtained as white crystals after drying.HPLC analytical conditions: the column was YMC-A-312, the detection wavelength was 254 nm, the flow rate was 1.0 mL/min, the eluent was methanol/water (9:1, v/v/v), and the buffer was a solution containing 0.1% triethylamine and acetic acid. The analytical results showed that the product composition was 1.3% fluorene, 98.4% 2-iodofluorene and 0.02% 2,7-diiodofluorene.
References
[1] Bulletin of the Chemical Society of Japan, 1989, vol. 62, # 2, p. 439 - 443
[2] New Journal of Chemistry, 2015, vol. 39, # 5, p. 4086 - 4092
[3] Patent: US6437203, 2002, B1
[4] Organic Electronics: physics, materials, applications, 2014, vol. 15, # 7, p. 1324 - 1337
[5] Journal of Materials Chemistry, 2012, vol. 22, # 12, p. 5319 - 5329
