Positive-ion mass spectra of sulfonamides

The mass spectral behavior of arenesulfonamides has been extensively studied1,3,69-73. The El mass spectra of various sulfonamides (103a-g, 104) have been investigated, revealing, in some cases, the occurrence of skeletal rearrangement processes69. Based on 

Arenesulfonamides bearing N-aryl substituent(s) showed in their mass spectra (a) abundant molecular ions (b) relatively minor fragments involving rearrangement, at [M — 64] + (loss of S02) and/or at [M - 65] + (loss of HS02) (c) predominant fragments 

Aftalion and Proctor71 examined the mass spectra of several tosylamides, derived from cyclic and aromatic amines, in the attempt to draw some generalizations on the electronic or conformational requirements which rendered the molecular ion prone to loss of S02. 

The mass spectra of sulfonamides, whose amido nitrogen pertains to an aliphatic cycle, have been investigated both in the El70,71,75 76 and ci77 modes. 

In the mass spectra of tosylated azetidines 111, the main fragmentation at the N—S bond was accompanied by cycle fragmentations, involving skeletal rearrangements with S02 expulsion, as shown in equation 3075. The mass spectrum of N-methanesulfonyl azetidine has been compared with that of N,AT-dimethyl methanesulfonamide, both displaying a methyl cleavage process from the molecular ion, in addition to the usual N—S fission75. 

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