Methyl 2-chloro-4-fluorophenylthioacetate as a new intermediate in the synthesis of pesticides

摘要

Recently, several types of highly effective herbicides containing the 4-chloro-2-fluoro-5-carbomethoxymethylthiophenyl group have been reported. Methyl 5-amino-2-chloro-4-fluorophenylthioacetate (2), a key intermediate in the preparation of these compounds, has been obtained from 4-chloro-2-fluoroacetanilide (1) in 19, 30 and 42 yields by routes 1, 2 and 3, respectively shown in Scheme 1. However, these procedures start from 1 which is expensive and involve lengthy sequences and the use of hazardous reagents such as fuming nitric, and sulfuric acids and sulfuryl chloride.