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A herbicide and sulfonylurea technology, applied in the field of fine organic chemistry, can solve problems such as low yield, high reaction temperature, and many side reactions
Active Publication Date: 2010-03-17
NANJING HUAZHOU PHARMA +1
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Yang Rongguo used ethyl 2-sulfonamide formate-N,N-dimethylnicotinamide to react with 2-amino-4,6-dimethoxypyrimidine, using toluene as solvent, rectifying at atmos
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Embodiment 1
[0013] Embodiment 1, the preparation of nicosulfuron
[0014] 23.3kg 150mol 2-amino-4,6-dimethoxypyrimidine, 30.1kg 100mol 2-sulfonamide ethyl formate-N,N-dimethylnicotinamide were put into the reaction kettle, and then 200L toluene was added, at 90℃ Under reduced pressure, the reaction was rectified under reduced pressure, ethanol was continuously removed, and the reaction of ethyl 2-sulfonamide formate-N, N-dimethylnicotinamide in the central control was complete. The temperature was lowered to 80°C, filtered, and dried. The yield of nicosulfuron was 99.5 % (calculated as pyridine sulfonamidate), the purity is 98.4%.
Embodiment 2
[0015] Embodiment 2, the preparation of nicosulfuron
[0016] The operation is the same as in Example 1, replacing 30.1kg 100mol ethyl 2-sulfonamide formate-N,N-dimethylnicotinamide with 28.7kg 100mol methyl 2-sulfonamide formate-N,N-dimethylnicotinamide, Results The yield of nicosulfuron was 96.2%, and the purity was 95.9%.
Embodiment 3
[0017] Embodiment 3, the preparation of pyrasulfuron-methyl
[0018] 23.3kg 150mol 2-amino-4,6-dimethoxypyrimidine, 29.8kg 100mol 2-sulfonamidoformic acid ethyl ester-3-trifluoromethylpyridine were put into the reaction kettle, then 200L toluene was added, and at 90°C, Rectification under reduced pressure, ethanol was continuously removed, and the reaction of ethyl 2-sulfonamidoformate-3-trifluoromethylpyridine in the central control was complete. The temperature was lowered to 80°C, filtered, and dried. The yield of nicosulfuron was 95.3%, and the purity was 96.7% %.
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Abstract
The invention discloses a synthesis method of a sulfonylurea weedicide, which comprises the followings steps: adding a compound I, a compound II and a methylcyclohexane or methylbenzene reaction solvent to a reactor; reacting at 80-100 DEG C under reduced pressure, and meanwhile, continuously rectifying alcohol produced in the reaction; and after the reaction finishes, carrying out the heat filtering at 60-80 DEG C to obtain the sulfonylurea weedicide. Since the reaction and the rectification are carried out under reduced pressure, the temperature is reduced, and the secondary reactions are reduced; pyrilamine is easily dissolved in hot methylbenzene but has low solubility in cold methylbenzene, and the sulfonylurea weedicide has low solubility in methylbenzene. By the method, the reaction, the rectification and the heat filtering are carried out under reduced pressure to obtain the high-yield high-purity sulfonylurea weedicid, thereby reducing the cost.
Description
technical field [0001] The invention belongs to the field of fine organic chemistry, and in particular relates to a synthesis method of a sulfonylurea herbicide. Background technique [0002] Sulfonylurea herbicide is one of the herbicides with the highest activity and the least dosage so far, and its industrial synthesis methods mainly include isocyanate method and carbamate method. The isocyanate method requires the use of highly toxic phosgene which is difficult to handle, and at the same time requires expensive catalysts n-butyl isocyanate and triethylenediamine. The isocyanate is very unstable and easy to deteriorate; the carbamate method requires the use of expensive diphenyl carbonate Or phenyl chloroformate, the expensive catalyst DBU (1,8-diazacyclo-(5,4,0)-7-undecene) needs to be used in the condensation reaction. Neither the isocyanate method nor the existing urethane method has a high yield, which is 75% to 85%, and the cost is relatively high. Later, it was pr...
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