Acyl azide
Carboxylic acid derivative
From Wikipedia, the free encyclopedia
Acyl azides are carboxylic acid derivatives with the general formula RCON3. These compounds, which are a subclass of organic azides, are generally colorless.[1]
Preparation
Typically acyl azides are generated under conditions where they rearrange to the isocyanate.[1]
Acid chlorides[2][3] and anhydrides[4] react with sodium azide[5] or trimethylsilyl azide[6] to give acyl azides:
In a Mitsunobu variant, triphenylphosphine and trichloroacetonitrile catalyze excellent yields from various carboxylic acids and sodium azide at mild conditions.[7]
The second major route to azides is from treating acylhydrazines with nitrous acid.[1][8] Alternatively, the acyl azide can be formed by the direct reaction of a carboxylic acid with diphenylphosphoryl azide (DPPA).[9][10]
Another route oxidizes aldehydes with iodine azide, formed from sodium azide and iodine monochloride in acetonitrile.[11]
Uses
On Curtius rearrangement, acyl azides yield isocyanates.[12][13]
Acyl azides are also formed in Darapsky degradation,[14][15][16]
Acyl azides react with amines to give aminimides (R3N+N−C(=O)R′).[17]
Historical references
- Curtius, Th. (1890). "Ueber Stickstoffwasserstoffsäure (Azoimid) N3H". Ber. (in German). 23 (2): 3023–3033. doi:10.1002/cber.189002302232.
- Curtius, Th. (1894). "20. Hydrazide und Azide organischer Säuren I. Abhandlung". J. Prakt. Chem. (in German). 50 (1): 275–294. doi:10.1002/prac.18940500125.
- Darapsky, August (1936). "Darstellung von α-Aminosäuren aus Alkyl-cyanessigsäuren". J. Prakt. Chem. (in German). 146 (8–12): 250–267. doi:10.1002/prac.19361460806.
- Darapsky, August; Hillers, Dietrich (1915). "Über das Hydrazid der Cyanessigsäure, Isonitrosocyanessigsäure und Nitrocyanessigsäure". J. Prakt. Chem. (in German). 92 (1): 297–341. doi:10.1002/prac.19150920117.