A new synthesis process of Halosulfuron-methyl
Chlorine pyrazole its cycling [belongs to sulfonylurea herbicide, developed by nissan chemical company, monsanto development. Applied for patent protection in 1984. Like other sulfonylurea herbicide is acetyl lactic acid synthase (ALS) inhibitors. Through the grass root and leaf absorption, conduction in plant body, weeds or stop growing, and then die. Its toxicity to human body and fish is very low. There is no "three".
Clopidosulfuron is widely used in wheat, maize, rice, sugarcane, grass and other crops, mainly to prevent broadleaf weeds and sedge weeds such as abutilon, cang ear, mandala and so on.Because of its rapid metabolism in crops as harmless, crop safety.It can be used before and after seedling.Effective composition of 70-90 grams of active ingredient/ha in pre-seedling dose and 18-35 grams of active ingredient/ha after seedling.
There are many methods for the synthesis of clopidosulfuron, the first one is to use pyrisulfuron-methyl ester as the starting material, and under the action of the catalyst, chlorpyrisulfuron is directly chlorinated.Method 2 is to use 3, 5 - dichloro - 1 - methyl - 4 - carboxylic acid methyl ester as the intermediates for synthesis of, is obtained by sulfhydryl, sulfonyl chloride acylation pyrazole sulfonamide, isocyanate and phosgene role again, its and 2 - amino - 4, 6 - dimethoxy pyrimidine reaction to chlorine pyrazole its cycling.Because the purity of the first method is difficult to control, the product contains incomplete chlorinated pyrisulfuron.The second method, although the steps are longer, the product quality is good.In the second method, the synthesis of the intermediate 3, 5-dichloro-1-methyl-4-carboxylate is very important.On the basis of relevant literature, the company (shouguang field chemical co., LTD.) has conducted a detailed study on its synthesis and found a suitable route for industrialization.
The synthesis route of 3, 5-dichloro-1-methyl-4-carboxylate 1 is shown.Using cross-linked with acetonitrile and cyano acetic acid methyl ester as starting materials, intermediates 2 - cyano - 3 - amino - 4,4,4 - acetone - 2-2 butenoic acid methyl ester, intermediates and hydrazine hydrate condensation get its amino - 4-3, 5 - two pyrazole formic acid methyl 3, then through diazotization chlorination yield of 3, 5 - dichloro - 4 - pyrazole formic acid methyl 4, the final target is obtained after dimethyl sulfate methylation compounds 1, this route is not only the cost is low, and industrial production is also relatively safe.The specific synthetic route is as follows:
The synthesis of chlorine pyrazole its cycling process of reactants, domestic procurement to entirely, simple operation, no low temperature or high pressure reaction, suitable for domestic general production enterprise production, every step yield high, raw material and production costs can control at a good level.This process has been by the fields of biological science and technology co., LTD. Weifang and hormones agricultural engineering technology research center co., LTD in jiangsu province for pilot and production, has achieved good results, the present stage for the nation's largest chloride pyrazole its cycling manufacturers.
Yuanye is a high-tech enterprise integrating scientific research and production of pesticide intermediates
