After 7.0 g of 9,9-di-n-butyl-2-nitrofluorene (5) (21.7 mmol) was dissolved in 200 ml of anhydrous nitrobenzene and 5.77 g of anhydrous aluminum chloride (43.4 mmol) was added thereto, the reaction mixture was heated to 45° C., and a solution in which 3.40 g of acetyl chloride (43.3 mmol) was dissolved in 40 ml of anhydrous nitrobenzene was slowly added thereto for 1 hour, followed by stirring at 65° C. for 1 hour. Thereafter, the reaction mixture was cooled to room temperature, 100 ml of distilled water was added thereto and stirred for about 30 minutes, followed by extracting the product with 200 ml of dichloromethane. The extracted organic layer was sequentially washed with 100 ml of saturated aqueous sodium bicarbonate solution and 100 ml of distilled water. Then, a solid product obtained by drying the recovered organic layer over anhydrous magnesium sulfate and distilling a solvent under reduced pressure was dispersed in a small amount of ether and stirred at room temperature for 30 minutes, followed by filtering and drying, thereby obtaining 5.44 g of 1-(9,9-di-n-butyl-7-nitrofluorene-2-yl)-ethanone (6) (68.7%) as a light yellow product.
