Mechanism of iodine migration during the nitrodeiodination of 4-iodoanisole
The conversion of 4-iodoanisole into 2-iodo-4-nitroanisole by nitric acid has been shown to occur by rapid nitrodeiodination and iodination to give 2,4-di-iodoanisole and 4-nitroanisole, gradual nitrodeiodination of the former compound at the 4-position with the production of free iodine, and then very slow iodination of the latter compound at the 2-position. Nitrous acid acts as a catalyst and the preliminary step is thought to be nitrosodeiodination. The ortho:para ratio for the methoxy-group in nitrosodeiodination is very low. The ipso factors of Perrin and Skinner are discussed in detail in the light of this and other work.