Study On The Synthesis Of Mesosulfuron-mehyl

Mesosulfuron-methyl was developed by Bayer Crop Science Company.It has the features of high efficiency,multiple targets and environment-friendly,and could be wi dely used in rice,corn,soybeans and other crops.At present,there is no mesosulfuro n-methyl manufacturers in China.Therefore,it is the purpose of this study to find an appropriate industrialized production method.In this paper,three synthetic routes were compared,and the amine methyl saccha rin was selected,and five key intermediates including 2-methyl-5-cyanobenzene sulfona mide,5-cyanosaccharin,5-aminomethylsaccharin,5-methanesulfonylaminomethyl sacchari n,2-methoxycarbonyl-5-methanesulfonylaminomethyl benzene sulfonamide were investigat ed.Moreover,the effect of each step on the yield was discussed.The results showed that Mesosulfuron-methyl was synthesized starting from p-tolun itrile via six steps of chlorosulfonation-aminiation,oxidation,reduction,methlsulfonylati on,alcoholysis and condensation.After the optimization of synthetic conditions,the yi eld of each step respectively is 78.5%,80.1%,92.9%,72.4%,82.3%,84.9%.And the total yield is 29.6%.By optimizing the reduction conditions of cyanide,the production cost was reduce d by replacing Pd/C which was reported in literature with Raney nickel.2-methoxycar bonyl-5-methanesulfonylaminomethyl benzene sulfonamide was synthesized by alcoholysi s of 5-methanesulfonyl-aminomethyl with acid resin.The reaction ended directly filtrati on,the recovered acid resin was applied to the next batch of synthesis,and the produ ct 2-methoxycarbonyl-5-methanesulfonylaminomethyl benzene sulfonamide was obtained from the oil layer to remove the solvent.In this way,the production of waste water in the process of synthesis is avoided.The route selected in this paper has the features of easily available raw materials,environmental protection and low cost,which is easy to implement in industrial and is worth promoting.