General procedure for the synthesis of 9,9-diphenyl-9,10-dihydroacridine from benzophenone and (2-bromophenyl)aniline: firstly, 10 g of (2-bromophenyl)aniline was dissolved in 100 mL of tetrahydrofuran, and the reaction system was subsequently cooled to -78 °C. At this temperature, 20 mL of 2.5 M butyl lithium solution was slowly added and stirred continuously for 1 hour. Next, 11 g of benzophenone was dissolved in 100 mL of tetrahydrofuran and slowly added dropwise to the reaction system. After the dropwise addition, the reaction temperature was gradually increased to room temperature and stirring was continued for 12 hours. Upon completion of the reaction, extraction was carried out with distilled water and dichloromethane, and the organic phase was dried with anhydrous magnesium sulfate, followed by filtration under reduced pressure to obtain the crude product. The crude product was dissolved in 100 mL of acetic acid, and 7 mL of concentrated sulfuric acid was added slowly and dropwise, and then the mixture was heated and refluxed and stirred. At the end of the reaction, it was again extracted with distilled water and dichloromethane. Finally, the resulting solid was purified by column chromatography to afford intermediate B-1 (7.1 g, 53% yield).
