A useful reagent for the Beckmann rearrangement and the synthesis of nitriles from carboxamides: N,N'-carbonyldiimidazole and reactive halides.

Ketoximes undergo the Beckmann rearrangement and primary carboxamides are dehydrated to nitriles on treatment with N, N'-carbonyldiimidazole and an excess of reactive halide. The reaction can be carried out in high yields under neutral reaction conditions by a simple procedure ; quaternization of the imidazole ring with reactive halides effectively promotes the reaction.