The collisional activation of protonated N-propyl-2-nitroaniline obtained by electrospray ionization shows two major competitive dissociation pathways: the elimination of the elements of propionic acid, [M + H - C3H6O2]+ to give an m/z 107 ion, and of the elements of ethanol, [M + H - C2H6O]+ to give an m/z 135 ion. The mechanistic study reported here addresses these unusual fragmentations to reveal that both occur via a common intermediate formed by the transfer of an oxygen atom from the nitro group to the first carbon atom of the propyl group, allowing elimination of propionic acid and (H2O + ethene), respectively. The corresponding loss of CH4O does not occur when the propyl group is replaced by an ethyl group, but elimination of the elements of propanol does occur when propyl is replaced by a butyl group. Further, the product ions of m/z 107 and 135 are also formed when the propyl chain is replaced with a hexyl group.

中文翻译：

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质子化的 N-烷基-2-硝基苯胺在碰撞活化时发生烷基链的分子内氧化

通过电喷雾电离获得的质子化 N-丙基-2-硝基苯胺的碰撞活化显示出两种主要的竞争性解离途径：消除丙酸元素，[M + H - C3H6O2]+ 得到 m/z 107 离子，以及乙醇的元素 [M + H - C2H6O]+ 得到 m/z 135 离子。此处报告的机理研究解决了这些不寻常的碎片问题，以揭示两者都是通过一个共同的中间体发生的，该中间体是通过氧原子从硝基转移到丙基的第一个碳原子形成的，从而消除丙酸和（H2O + 乙烯）， 分别。当丙基被乙基取代时不会发生相应的 CH4O 损失，但当丙基被丁基取代时会发生丙醇元素的消除。更多，