Study On The Synthesis Of New Herbicide Pyrasulfotole And Its Analogues

The article briefly reviewed 4-hydroxyphenylpyruvate dioxygenase(HPPD)and herbicides that target it,and the property,mechanism and synthesis route of Pyrasulfotole were introduced in detail.We found a synthesis route of Pyrasulfotole that had a bright industrialization value through comparing the merits and demerits of all methods in the literature.In this paper,2-methylsulfonyl-4-trifluoromethyl benzoic acid was prepared by means of nitration,cyanation,methyl mercaptan substituted,hydrolysis and oxidation from inexpensive 4-Chlorobenzotrifluoride.And from it,we synthesized the benzoyl chloride,then pyrasulfotole has been gotten by means of esterification and rearrangement by catalyzing with Acetone cyanohydrin.And the synthesis technology of every step was improved by reference to the literature.The new process is more convenient and the yield is higher.The structure of the products was determined by IR,NMR and MS.The purity is determined by HPLC or GC.We designed and prepared eight Pyrasulfotole analogues,confirmed the structure of all intermediates and target products.Grass killing activity test showed that all analogues have herbicidal activity and three of them have excellent herbicidal activity.