Study On The Synthesis Of Chlorfenapyr

Chlorfenapyr, 4-bromo-2-(4-cholorphenyl)-1 -ethoxymethyl-5-trifluoro methylpyrrole-3-carbonitrile, is a novelty pyrrole acaricide with high activity and long durability. In the paper , a novel process for the synthesis of Chlorfenapyr has been developed. In this process, Chlorfenapyr is prepared from chlorophenylglycine, trifluoroacetic acid and 2-chloroacrylonitrile via lactonization, pyrrole cyclization, bromization and ethoxymethylization. The overall yield of Chlorfenapyr is about 73～74% and the purity is >99%, which are 4%～5% higher than the domestic average level. The expensive and carcinogenic trifluoroacetic anhydride and dibromomethane, which are using in the current domestic process, were replaced by trifluoroacetic acid and methylene diethyl ether respectively. The raw materials are abundant in China, and the reaction conditions are mild, so it can be suitable for industrial manufacturing.