22233-52-9

42087-81-0

22233-52-9

This embodiment relates to the synthesis of 3-chloro-2-nitrobenzaldehyde: to a stirred solution of methyl 2-nitro-3-chlorobenzoate (2.91 g, 13.5 mmol) and dichloromethane (134 mL) was slowly added diisobutylaluminum hydroxide (DIBAL-H, 16.0 mL, 16.0 mmol, 1.0 M in dichloromethane) at -78°C for a period of more than 15 minutes. After completion of the addition, stirring was continued for 10 minutes, followed by quenching the reaction with methanol (1.0 mL) and allowing the reaction mixture to warm slowly to room temperature. Next, aqueous sodium potassium tartrate (190 mL, 10% w/v) was added and the reaction mixture was stirred vigorously.After 4 h, the reaction mixture was diluted with dichloromethane (50 mL) and washed sequentially with water (3 x 100 mL) and saturated aqueous sodium bicarbonate (100 mL). The organic layer was dried over anhydrous magnesium sulfate and subsequently concentrated under reduced pressure. The crude product was purified by recrystallization with ethyl acetate/hexane (1:3) to afford the target product 3-chloro-2-nitrobenzaldehyde (2.32 g, 12.7 mmol, 94% yield) as a white crystalline solid. The structure of the product was confirmed by 1H NMR (400 MHz, CDCl3) and 13C NMR (100 MHz, CDCl3).