Synthesis
Magnesium chips (26.4 g, 1.1 mol) and tetrahydrofuran (160 mL) were added to the reaction flask under nitrogen protection, and a mixture of 1-bromo-2,3-dimethylbenzene (18.5 g, 0.1 mol) and tetrahydrofuran (100 mL) was added dropwise with stirring at room temperature to initiate the reaction. Subsequently, a mixture of 1-bromo-2,3-dimethylbenzene (166.5 g, 0.9 mol) and tetrahydrofuran (1000 mL) was added dropwise to the reaction system. After the dropwise addition, the reaction mixture was refluxed for 1 hour. The resulting Grignard reagent was cooled in an ice bath and a mixture of N,N-dimethylformamide (73 g, 1.0 mol) and tetrahydrofuran (300 mL) was added dropwise slowly, controlling the reaction temperature to not exceed 20 °C. The reaction temperature was then increased by 1 h at room temperature. After the dropwise addition was completed, the reaction was continued to be stirred for 2 hours at room temperature. At the end of the reaction, the reaction was quenched by the addition of saturated aqueous ammonium chloride solution (1000 mL) and left to stratify. The organic phase was separated and the aqueous phase was extracted with ethyl acetate. The organic phases were combined, washed with saturated saline (500 mL) and left to stratify. The organic phase was dried with anhydrous sodium sulfate (50 g), filtered and concentrated to dryness under reduced pressure to give 2,3-dimethylbenzaldehyde in 96% yield and 96.2% purity.
