Fragmentation patterns upon electron ionization of N-(2-nitrophenyl)-methanesulfonamide and selected N-alkyl-N-(2-nitrophenyl)-methanesulfonamides are described. It is observed that the molecular ions of the latter compounds undergo rearrangement reactions resulting in the loss of the molecule of an appropriate carbonyl compound. The molecular ion of N-(2-nitrophenyl)-methanesulfonamide also undergoes rearrangement reaction yielding a benzofurazane radical cation. Proposals for the appropriate “ortho-effect” based reaction mechanisms are given.
