NaClO2/NaI in the presence of HCl is a mild, cheap, and non-toxic reagent for the iodination of phenols, including estradiol and naphthol, aromatic amines, and heterocyclic substrates, eg, indoles, 8-hydroxyquinoline, imidazole, in fair to excellent yields by a very simple isolation protocol. The scope of the procedure is exemplified by the first iodination of 5- nitroindole to 3-iodo-5-nitroindole in 75% yield.
[Shirtcliff, Laura D.; Weakley, Timothy J. R.; Haley, Michael M.; Koehler, Felix; Herges, Rainer Journal of Organic Chemistry, 2004 , vol. 69, # 21 p. 6979 - 6985]
