Synthesis of Aromatic Azides using Different Methodologies

For several decades, aromatic azides have been applied in diverse areas of research like synthesis of organic compounds, novel materials and photoaffinity labeling of biomolecules. The discovery of click chemistry and bioorthogonal chemistry expanded their applications. Currently, they are extensively used in biology, biochemistry and medicine. For many years, aromatic azides were usually prepared using nucleophilic substitution. In this classical procedure, commercially available anilines are first converted into aryl diazonium salts which in turn are transformed into aromatic azides by nucleophilic substitution with sodium azide. However, this procedure is rather inconvenient experimentally since it requires the use of strong acids and low temperatures. In recent years, several alternative procedures have been developed. In the present review, we present the synthesis of aromatic azides by means of different experimental methodologies.