203070-78-4

75-21-8

86-73-7

203070-78-4

Add raw fluorene (100g) to N,N-dimethylformamide (750ml) and stir under nitrogen protection until the solid is completely dissolved. Sodium hydride (60 g in 3 to 4 portions at 15 min intervals) was added in batches at 0 °C, controlling the reaction temperature at 0 to 5 °C (note that there was a large amount of gas release). After addition, the reaction temperature was maintained at 0 to 10°C with stirring for 1 hour, followed by cooling to 0°C. Dilute ethylene oxide (60 ml) with N,N-dimethylformamide (50 ml) and add it dropwise to the reaction vial within 1 min. After the dropwise addition, the temperature was slowly increased to 15°C and the reaction was kept at this temperature for 5 hours. The reaction mixture was slowly poured into 800 g of ice water and extracted with ethyl acetate (800 ml x 3). The organic phases were combined, washed once with saturated brine (800 ml) and dried over anhydrous sodium sulfate. After filtration to remove the desiccant, it was concentrated by rotary evaporation to half of the original volume (water bath temperature about 45°C) and decolorized by adding 10 g of activated carbon for half an hour. The activated carbon was removed by filtration and the solvent was concentrated again (water bath temperature about 45°C) to give 170 g of crude product. The crude product was dissolved in 510 ml of toluene, heated to 100°C to dissolve, then slowly cooled to room temperature (10-15°C) and left to crystallize for 2 hours. It was filtered, and the filter cake was washed with toluene (100 ml x 2) and dried at 60°C and -0.09 MPa to give 63 g of off-white powder. The above product was dissolved with 210 ml of toluene heated to 100 °C, slowly cooled to room temperature (10-15 °C) and crystallized for 2 h. The product was filtered, the filter cake was washed with toluene (100 ml x 1) and dried at 60 °C, -0.09 MPa to give 61 g of white crystals (Intermediate 2). The molar yield was 40.1% and the HPLC purity was 99.7%. Note: After the addition of ethylene oxide, the reaction temperature must be strictly controlled at 10 to 15 °C and must not exceed 20 °C.