Nitrile Oxide Formation from Nitroalkanes

Dehydration with Isocyanates

Reaction of aliphatic nitro compounds with the dehydrating agent phenyl isocyanate (Ph–N=C=O), which removes a molecule of water atom-by-atom to give aniline (PhNH₂) and CO₂. Two slightly different mechanisms are shown, the last step might not be concerted.

An alternative synthesis of nitrile oxides is by elimination from chloroximes.

Nitrile oxides are used in the formation of isoxazoles via cycloaddition.

T. Mukaiyama and T. Hoshino, J. Am. Chem. Soc., 1960, 82, 5339–5342.