Orton Rearrangement

Abstract

This reaction is the rearrangement of an N ‐chloro acyl anilide into an N ‐acyl p ‐chloroanilide in the presence of an acid such as HCl and is generally known as the Orton rearrangement. This reaction proceed via a multistep processes and is promoted simultaneously by proton (i.e., H + ) and chloride. It has been found that both solvent composition and substrate influence this rearrangement. In addition, the Orton rearrangement can be triggered by a Lewis acid as well as by light. Furthermore, it has been reported that the chlorination of acyl anilide from chlorine can proceed by two paths and the ortho/para ratio of isomers increase when the solvent viscosity is increased. This reaction is useful for the preparation of para ‐halo anilides.