A 33% aqueous methylamine solution (17.5 mL, 140 mmol) was slowly added dropwise to a dichloromethane solution (120 mL) containing ethyl 4-chloro-2-methylthiopyrimidine-5-carboxylate (10.0 g, 43.1 mmol) at 0 °C. The reaction mixture was stirred at this temperature for 30 minutes. The reaction mixture was stirred at this temperature for 30 minutes. Subsequently, it was quenched by the addition of water (150 mL), the organic phase was separated and dried over anhydrous magnesium sulfate. After filtration, the filtrate was concentrated under reduced pressure to afford the product ethyl 4-methylamino-2-methylthio-5-pyrimidinecarboxylate (9.77 g, 100% yield) as a white solid.
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