Synthesis method of picolinafen

Abstract

The invention provides a synthesis method of picolinafen. The synthesis method comprises the following steps: reacting 2-chloro-6-trichloromethyl pyridine (formula II) with 3-trifluoromethyl phenol (formula III) to generate 2-(3-trifluoromethylphenoxyl)-6-trichloromethyl pyridine (formula IV); converting 2-(3-trifluoromethylphenoxyl)-6-trichloromethyl pyridine (formula IV) into 2-(3-trifluoromethylphenoxyl)-6-pyridine formyl chloride (formula V); and reacting 2-(3-trifluoromethylphenoxyl)-6-pyridine formyl chloride (formula V) with 4-fluoroaniline to generate picolinafen (formula I). By synthesizing a key intermediate namely 2-(3-trifluoromethylphenoxyl)-6-trichloromethyl pyridine (formula IV), the reaction route is well simplified, moreover, the reaction conditions can be reached easily, the product yield is high, and the synthesis method has a good value for scientific research and can be used in industry.

Description

technical field [0001] The invention belongs to the technical field of drug synthesis, and in particular relates to a method for synthesizing flumezachlor. Background technique [0002] Flufenachlor (Formula I) is an amide herbicide developed by BASF, which belongs to carotenoid biosynthesis inhibitors. Its common name is picolinafen, and its CAS accession number is [137641-05-5]. [0003] Document WO2007051759 reports two routes for the synthesis of flumezachlor (formula I). The first route is to use 2-chloro-6-trichloromethylpyridine as a raw material, first react with sulfuric acid to convert 2-chloro-6-pyridinecarbonyl chloride, the latter reacts with 4-fluoroaniline to form an amide, and finally the amide reacts with 3 - Condensation of trifluoromethylphenol to give flumezachlor (formula I): [0004] ; [0005] The second route is to esterify 2-chloro-6-pyridinecarbonyl chloride and alcohol into an ester, and then condense the latter with 3-trifluoromethylphenol to...

AI Technical Summary

Problems solved by technology

[0007] However, when route one condenses amides and 3-trifluoromethylphenol, because the amide steric hindrance is relatively large, the reaction is not easy to carry out, and the yield of the product is difficult to improve; route two has one more step of esterification reaction compared with route one, In addition, the reaction between ether ester and 4-fluoroaniline requires strong alkalinity and high temperature conditions, the reaction route is long, and the reaction conditions are relatively harsh, so it is difficult to achieve