5-fluorocytosine preparation method
A technology of fluorocytosine and methyl fluoroacetate, which is applied in the field of preparation of 5-fluorocytosine, can solve problems such as high cost, complex equipment, and large pollution, and achieve reduced production cycle and cost, easy recycling, and reduced waste liquid The effect of emissions
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[0032] The specific operation steps of the preparation method of 5-fluorocytosine include:
[0033] a. Add sodium methoxide to toluene in batches. After the addition, first add ethyl formate dropwise, then add methyl fluoroacetate dropwise. After the dropwise stirring is completed for 1.0-2.0 hours, heat up to 36-38°C for 5-8 hours; Then add methanol and sodium methoxide, stir and lower the temperature to 15-25°C, then add urea to react for 4-6 hours. Adjust the pH to 3-4 with hydrochloric acid, control the temperature below 20°C and stir for 1-2 hours; filter to obtain a solid, wash with water to obtain compound 5-FU;
[0034] b. 5-FU, thionyl chloride and DMF are heated up to reflux reaction until the content of 5-FU is ≤0.2%. After the reaction is over, atmospheric distillation recovers thionyl chloride, and then distillation under reduced pressure yields compound 5- FU-1; Wherein, DMF is as the catalyst of chlorination reaction;
[0035] c. Heat ammonia water and 5-FU-1 ...
Embodiment 1
[0056] a. In a 1L three-necked flask, nitrogen gas was introduced, and toluene (500 g) was added. Sodium methoxide (52.9 g, 0.98 mol) was added in batches, and the temperature was controlled below 30°C. After the addition, the temperature was lowered to 10°C, and ethyl formate (72.5 g, 0.98 mol) was added dropwise. During the dropwise addition, the temperature of the reaction system was controlled at 10-20°C.
[0057] After the ethyl formate was added dropwise, methyl fluoroacetate (60 g, 0.65 mol) was added dropwise, and the temperature was controlled at 15-20°C during the dropwise addition. After dripping and stirring for 1.0 h, the temperature was raised to 36-38° C., and the reaction was stirred for 5 h. Add methanol (65g) and sodium methoxide (30g, 0.56mol), stir and cool down to 20°C.
[0058] Urea (67.2 g, 1.12 mol) was added, and the reaction was stirred at room temperature (28° C.) for 5 hours. Recover methanol by desolvation under reduced pressure, and then add wa...
Embodiment 2
[0063] a. In a 1L three-necked flask, nitrogen gas was introduced, and toluene (500 g) was added. Sodium methoxide (52.9 g, 0.98 mol) was added in batches, and the temperature was controlled below 30°C. After the addition, the temperature was lowered to 10°C, and ethyl formate (72.5 g, 0.98 mol) was added dropwise. During the dropwise addition, the temperature of the reaction system was controlled at 10-20°C.
[0064] After the ethyl formate was added dropwise, methyl fluoroacetate (60 g, 0.65 mol) was added dropwise, and the temperature was controlled at 15-20°C during the dropwise addition. After dripping and stirring for 1.0 h, the temperature was raised to 36-38° C., and the reaction was stirred for 5 h. Add methanol (65g) and sodium methoxide (30g, 0.56mol), stir and cool down to 20°C.
[0065] Urea (67.2 g, 1.12 mol) was added, and the reaction was stirred at room temperature (28° C.) for 5 hours. Recover methanol by desolvation under reduced pressure, and then add wa...
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