4269-17-4

54245-41-9

4269-17-4

To a 500 mL three-necked flask were sequentially added 50 mL of benzyl cyanide, 70.7 g (0.3 mol) o-dibromobenzene and 68.4 g (0.45 mol) cesium fluoride. Under argon protection, 0.86 g (1.5 mmol) of bis(dibenzylideneacetone)palladium, 2.86 g (15 mmol) of thiophene-2-carboxylate, and 7.0 g (15 mmol) of 1,1'-bis(di-tert-butylphosphino)ferrocene were added as catalyst. The reaction mixture was stirred at 150°C for 24 hours. After completion of the reaction, it was cooled to room temperature, the reaction mixture was filtered and the filtrate was distilled to remove benzyl cyanide to give the crude product 2-bromo-2'-carbonitrile biphenyl. The crude product was transferred to another 500 mL three-necked flask and 80 mL of glacial acetic acid and 80 mL of concentrated sulfuric acid were added. After heating and refluxing for 12 hours, it was cooled to room temperature and filtered to obtain a dark yellow solid. The solid was washed with 100 mL of water and 100 mL of methanol and finally recrystallized from 200 mL of isopropylbenzene to give 61.9 g (80% yield) of 4-bromo-9H-fluoren-9-one as a yellow solid.