Study On The Synthesis Of Epoxiconazole And Chlorantraniliprole Intermediates

Pesticides are an important means for people to control diseases in agriculture,forestry and animal husbandry.Since the emergence of pesticides,they have experienced three eras of natural medicine,inorganic synthesis and organic synthesis.Their efficacy has been continuously improved,and the pollution of pesticides to the environment has become increasingly serious.In the new era,people are not only pursuing the high activity,high selectivity,low toxicity of pesticides themselves,but also infiltrating green chemicals into every step of preparing pesticides.In this paper,intermediates of two pesticides,epoxiconazole and chlorantraniliprole,were selected and their synthesis processes were studied.The content of the epoxiconazole intermediate part is that factory prepares Z-1-chloro-3-(2-chlorophenyl)-2-(4-fluorophenyl)-2-propene by dehydration of 1-chloro-3-(2-chlorophenyl)-2-(4-fluorophenyl)-2-propanol and this process produces a lot of useless E-isomers.A standard analytical method was first established using high performance liquid chromatography.Then the two main ideas of catalyzing olefin mother liquor and re-screening dehydration conditions are studied.The idea of catalyzing olefin mother liquor uses three methods of thermal catalysis,photocatalysis and catalyst catalysis.Both photocatalysis and catalyst catalysis have a conversion effect when acting on the pure E-isomer,but do not achieve the desired effect when acting on the olefin mother liquor.Then the dehydration conditions of 1-chloro-3-(2-chlorophenyl)-2-(4-fluorophenyl)-2-propanol is re-screened.Under optimal conditions,the yield of Z-isomer is 81.45%,the Z/E ratio is as high as 10.21.The content of chlorantraniliprole is to explore a suitable process for the synthesis of the important intermediate 2-amino,5-chloro-N,3-dimethylbenzamide.The target compound was synthesized in three steps using 2-amino-3-methylbenzoic acid as a starting material.The first step of the chlorination reaction replace the chlorine gas by a combination of hydrogen peroxide and hydrochloric acid,which is safe and easy to operate and highly selective;the second step of the cyclization reaction uses saturated sodium carbonate to absorb the exhaust gas and by-products,and uses a water spray method to further reduce the harm to the environment;the third step selects the appropriate methylamine species and other parameters,the final product has a purity of 99.2%.The three-step synthesis has a yield of 57.5%,the reaction conditions are mild and simple,environmentally friendly,and initially meet the requirements of industrialization.