Sequentially, 800g of 2-thiouracil and 6L of water were added to a 10L reaction flask and stirred. Ice bath cooling, add sodium hydroxide 560g to the reaction bottle in batches, maintain the temperature below 40. After the addition, the ice bath was cooled down to below 20 , and 944g of dimethyl sulfate was slowly added dropwise, and the temperature was controlled between 15-25 during the dropwise process, and after the dropwise process, the reaction was kept warm for 4 h. The raw materials were basically reacted by HPLC. The reaction solution was adjusted to pH 1-2 with 6 mol/L dilute hydrochloric acid, and a white solid was precipitated. Decrease to about 20 , stirring 0.5h, filtration, filter cake with a large number of water to remove salt, pump dry, 50 air drying. Obtained 805g of white solid powder, more than 98% of the liquid phase, yield 90.7%.
