Phosphorus pentoxide is commonly used for the dehydration of heterocyclic carboxamides to the corresponding nitriles. In this report, the use of cyanuric chloride/N,N-disubstituted formamide for this reaction is described. The advantages of this procedure are mild reaction conditions and good yields. Depending on the reaction conditions and the structures of the amides, the nitriles are obtained in yields from 51% to 99%. Several of the oxazole carbonitriles synthesized by this procedure have not yet been described.
Aquino, F., Karge, R., Pauling, H., & Bonrath, W. (1997). Dehydration of aromatic heterocyclic carboxamides to aromatic heterocyclic carbonitriles. Molecules, 2(11), 176–179. https://doi.org/10.3390/21100176