Efficient and Practical Route for 3,5-Dichloro-4-(1,1,2,2-tetrafluoroethoxy)aniline: a Key Intermediate of Hexaflumuron

An improved and practical route is reported here for accessing 3,5-dichloro-4-(1,1,2,2-tetrafluoroethoxy)aniline ( 1 ), a key intermediate of hexaflumuron. The overall yield for the preparation of 1 is 74.0%, with a purity of 99.7%, after a one-pot process with catalytic hydrogenation and Bamberger rearrangement and a greener addition reaction in a continuous flow reactor. Compared with the original process route, the new synthetic route has the advantages of fewer reaction steps, higher overall yield, less process safety hazard and environmental impact.