Study On Synthesis Of The Higha Ctivity Herbicide Rimsulfuron

This thesis is about the study of the preparation and production process of sulfonylurea herbicide rimsulfuron. Being extensive, high effectual, rimsulfuron is widely used in preventing or killing many types of weeds with broad leaves and gramineaes in the field of corn, tomato or potato. Being low toxic, easily degradation in the environment and short half live in the soil, rimsulfuron became one of the extrusive sulfonylurea herbicides.It was synthesized from 1, 1, 3, 3-tetramethoxypropane and ethylsul fonyl acetonitrile as starting materials. Rimsulfuron was synthesized by elimination-addition, displacement reaction, cyclization reaction, sulph reaction, sulfonamination reaction, condensation reaction. The total yield was 38.8%, and the content was above 98.5%. The influence of reaction conditions on the result of each intermediate was studied and the tech-nical parameter was optimized. The structures of product and intermediates were comfimed by ~1HNMR, IR and MS.In this thesis, the synthetic method of 2-Bromo-3-(ethylsulfonyl)-Pyridine and the method for purification of intermediates were improved and simpfiled. Phenyl N-(4, 6-dimethoxypyrimidin-2-yl)carbamate was synthesized with the BTC route avoiding the severe toxic phosgene in the thesis, which is much suitable to the demand of the environmentally and benign chemistry.