Acyl azides are carboxylic acid derivatives with the general formula RCON3. These compounds, which are a subclass of organic azides, are generally colorless.[1]
Typically acyl azides are generated under conditions where they rearrange to the isocyanate.[1]
Alkyl or aryl acyl chlorides react with sodium azide to give acyl azides.[2][3]
The second major route to azides is from the acyl hydrazides with nitrous acid.[1]
Acyl azides have also been synthesized from various carboxylic acids and sodium azide in presence of triphenylphosphine and trichloroacetonitrile catalysts in excellent yields at mild conditions.[4] Another route starts with aliphatic and aromatic aldehydes reacting with iodine azide which is formed from sodium azide and iodine monochloride in acetonitrile.[5]
On Curtius rearrangement, acyl azides yield isocyanates.[6][7]
Acyl azides are also formed in Darapsky degradation,[8][9][10]
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