2,4,6-Trichlorobenzaldehyde

108-70-3

68-12-2

24473-00-5

2.8.2 Synthesis of 2,4,6-trichlorobenzaldehyde (6b): 1,3,5-trichlorobenzene (1.81 g, 10 mmol) was dissolved in anhydrous tetrahydrofuran (36 mL) under dry conditions and stirred at -78°C. The solution was then dissolved in anhydrous tetrahydrofuran (36 mL). N-butyllithium (1.6 M hexane solution, 6.3 mL, 10 mmol) was slowly added dropwise to the above solution over a period of 0.5 h. The solution gradually changed to a light yellow color. After the dropwise addition was completed, stirring was continued at -78 °C for 0.5 hours. Subsequently, anhydrous N,N-dimethylformamide (1.32 mL, 17 mmol) was slowly added dropwise to the reaction mixture and stirring was continued at -80 °C to obtain a light yellow solution. The reaction system was warmed up to -78 °C and kept for 1.5 hours. Upon completion of the reaction, the reaction was quenched with 3N hydrochloric acid solution (36 mL) while keeping the reaction vial at -78 °C and gradually warmed to room temperature to obtain a colorless solution. The reaction mixture was extracted with ethyl acetate (20 mL x 3) and the organic layers were combined and washed sequentially with saturated aqueous sodium bicarbonate solution and brine. The organic layer was dried over anhydrous magnesium sulfate and concentrated under reduced pressure to give the white needle-like solid product 6b (1.99 g, 96% yield). The structure of the product was determined by nuclear magnetic resonance hydrogen spectroscopy (1H NMR, 500 MHz, CDCl3) δ 10.43 (s, 1H), 7.42 (s, 2H); nuclear magnetic resonance carbon spectroscopy (13C NMR, 125 MHz, CDCl3) δ 187.7, 139.4, 137.8, 130.0, 128.8; and high resolution mass spectroscopy (HRMS. ESI) m/z: C7H4Cl3O [M+H]+ calculated value 208.92, measured value 208.9 for confirmation.