General procedure: 38 g of 3-hydroxy-2-methylpyridin-4(1H)-one was added to a reaction flask and dissolved in a mixed solution of 90 g of water and 35 g of potassium hydroxide with stirring. The reaction temperature was controlled at 10~20°C. 75 g of dimethyl sulfate was slowly added dropwise, and the reaction was held at the same temperature for 20 hours after the dropwise addition. After completion of the reaction, 80 g of dichloromethane was added to the reaction mixture, stirred for 15 minutes and left to stratify. The aqueous layer was extracted once more with 20 g of dichloromethane, stirred for 15 minutes and left to stratify. The two dichloromethane layers were combined and concentrated under reduced pressure. The product was dried under reduced pressure to give 44 g of 3,4-dimethoxy-2-methylpyridine.
