623-12-1

68-12-2

13719-61-4

The general procedure for the synthesis of 2-chloro-5-methoxybenzaldehyde from 4-chloroanisole and N,N-dimethylformamide was as follows: 20 g of 4-chloroanisole was dissolved in 230 mL of tetrahydrofuran and cooled to -78 °C. 130 mL of 2.5 M n-butyllithium solution was slowly added under stirring, maintaining the temperature at -78 °C, and the reaction mixture continued to be stirred for 2 hours. Subsequently, N,N-dimethylformamide was added and the reaction mixture was allowed to warm naturally to room temperature and stirred overnight. Upon completion of the reaction, the reaction was quenched by the addition of 1 N hydrochloric acid solution and then the mixture was extracted with ethyl acetate. The organic phase was separated, dried over anhydrous sodium sulfate and concentrated under reduced pressure to give 17 g of 2-chloro-5-methoxybenzaldehyde.