2-Ethoxy-4,6-dichloropyrimidine is an important heterocyclic pesticide and pharmaceutical intermediate. It can be used to synthesize highly effective herbicides containing triazole pyrimidine rings, such as dichlorvos and chlorpyrifos; it can also be used to synthesize certain antibiotics. Therefore, 2-ethoxy-4,6-dichloropyrimidine has broad application prospects in organic synthesis, pharmaceuticals, and pesticides.
To a 500 mL reaction flask equipped with a stirrer and thermometer was added 43.5 g of 2-methylsulfonyl-4,6-dichloropyrimidine (0.19 mol) and 90 g of ethanol and stirred at room temperature. The reaction mixture was then cooled to 0 °C and 130 g of sodium ethanol solution (0.38 mol) at a concentration of 20 wt% was slowly added dropwise. Upon completion of the reaction, the reaction was terminated by sampling and analysis to confirm that the feedstock content was less than 1%. After adjusting the reaction system to neutral pH, a small amount of acetic acid was added and ethanol was recovered under reduced pressure. Subsequently, dichloromethane was added, the solvent was evaporated and water was added to separate the organic layer. The organic layer was washed once with water and the first solvent was recovered. 35.2 g of 2-ethoxy-4,6-dichloropyrimidine was obtained in 95.2% yield and 96.5% purity (HPLC analysis) by distillation under reduced pressure until no liquid was exuded.
