19190-91-1

83-32-9

19190-91-1

The general procedure for the synthesis of 5,6-dibromo-1,2-dihydroacenaphthene from acenaphthene was as follows: compound C (4,5-dibromonaphthalene) was prepared as follows: 37.01 g (240 mmol) of acenaphthene and 200 mL of N,N-dimethylformamide (DMF) were added to a 500 mL two-necked flask, and the reaction temperature was maintained at 13 °C with continuous stirring. 103.23 g (580 mmol) of N-bromosuccinimide (NBS) was dissolved in 200 mL of DMF and then slowly added dropwise to the DMF solution of acenaphthene through a dropping funnel, and the dropwise process was completed in about 5 hours. After the dropwise addition, the reaction mixture was continued to be stirred at room temperature overnight. After completion of the reaction, vacuum filtration was carried out to collect the solid residue. The residue obtained by filtration was mixed with 100 mL of ethanol and refluxed for 10 hours. The reaction mixture was cooled at room temperature and filtered again to obtain 24.3 g of off-white solid product in 32.45% yield.