Azides

Inorganic and organic azides (RN₃) likewise have fascinated scientists for over 150 years now. These versatile compounds have a very broad application spectrum due to their chemical reactivity, which is often orthogonal to a lot of chemical functionalities and thus is ideally suited to introduce chemical diversity in the presence of other reactive chemical functions without alternation of the latter. Besides, azides frequently allow for very mild reaction conditions tolerating a lot of other chemical functionalities as well as moisture and air. Thus, this has led to some general applications like the Staudinger ligation or the concept of Click chemistry which have found widespread use beyond the chemicals borders, eg, in biochemistry, polymer, and material sciences. Some azides are produced on industrial scale and are used, for example, in the automotive sector.

Although azides are multipurpose compounds in chemistry and beyond, their laboratory and especially their industrial production have always been limited by their acute toxicity and their explosive nature. A lot of inorganic and organic azides are indeed highly toxic and their more or less pronounced tendency to liberate nitrogen gas (N₂) spontaneously upon shock, heating or electric discharge in an explosive fashion makes them relatively tricky to handle, especially on a large scale.

Regardless of the health and safety issues, azides have never been completely abandoned by the scientific community and have known several revivals during their 150 years old history. Whenever dealing with azides, one should however always bear in mind their potential toxicity and explosive tendency and handle them accordingly.

Keywords: Azide; Staudinger reaction and ligation; Schmidt rearrangement; Curtius rearrangement; aza-Wittig; Click Chemistry; Cycloadditions