A New, Simple, and General Synthesis of N -Oxides of Iodopyridines and Iodoquinolines via the Diazotization–Iodination of Heterocyclic Amino N -Oxides in the Presence of p -Toluenesulfonic Acid in Water

The diazotization of a series of N -oxides of aminopyridines and aminoquinolines under the action of sodium nitrite in the presence of KI and p -TsOH in water at room temperature leads to the formation of the corresponding N -oxides of iodopyridines and iodoquinolines in high yields. The method has a general character and can be used for the preparation of 3-, 2-, and 4- N -oxides of iodopyridines.