US Patent 11180443 Preparation method for m-diamide compounds

The present disclosure provides a preparation method for m-diamide compounds. The method includes the following steps: 2-fluoro-3-nitrobenzoyl chloride and 4-(perfluoropropane-2-yl)-2-(trifluoromethyl)aniline are subjected to a condensation reaction, followed by a reduction reaction and an alkylation reaction to give 2-fluoro-3-(alkylamino)-N-(4-(perfluoropropane-2-yl)-2-(trifluoromethyl)phenyl)benzamide, which reacts with an acyl chloride compound to give 2-fluoro-3-(alkylbenzamido)-N-(4-(perfluoropropane-2-yl)-2-(trifluoromethyl)phenyl)benzamide, which is finally brominated to obtain the m-diamide compound. The reactions are almost quantitative with few by-products. Cryogenic and high-temperature reactions are not used. The introduction of bromine atoms at specific sites can be achieved in the final step. The preparation method has high yield and is more suitable for industrial production.