52.5 g (0.16 mol) of 2,7-dibromo-9-fluorenone, 154.8 g (0.93 mol) of ethyl salicylate, and 1.4 g (0.016 mol) of mercaptoacetic acid were placed into a flask having a volume of 3,000 mL, and the atmosphere in the flask was replaced by nitrogen gas. Methanesulfonic acid (630 mL) was further added into the flask and the mixture was stirred overnight at 75° C. The mixture was allowed to cool. When the mixture was added to ice water and the resultant mixture was stirred for 1 hour, a solid was generated. The generated solid was separated by filtration and the solid was washed with heated acetonitrile. The washed solid was dissolved into acetone. A solid was obtained by recrystallization from the obtained acetone solution and separated by filtration. The obtained solid (62.7 g), 2-[2-(2-methoxyethoxy)ethoxy]ethoxy-p-toluenesulfonate (86.3 g, 0.27 mmol), potassium carbonate (62.6 g, 0.45 mmol), and 18-crown-6 (7.2 g, 0.027 mol) were dissolved into N,N-dimethylformamide (DMF) (670 mL). The obtained solution was transferred to a flask and stirred overnight at 105° C. The obtained solution was allowed to cool to the room temperature. The mixture is added to ice water, and the resultant mixture was stirred for 1 hour. Chloroform was added the solution to perform liquid separation and extraction. 2,7-dibromo-9,9-bis[3-ethoxycarbonyl-4-[2-[2-(2-methoxyethoxy)ethoxy]ethoxy]phenyl-fluorene (compound B) (51.2 g) was obtained by concentrating the obtained solution. The yield was 31%.
