In this study, the gas-phase fragmentations of molecular ions of thioanisole derivatives were investigated using electron ionization mass spectrometry (EI-MS). In the EI-MS spectrum, a characteristic fragment ion [M − SH]⁺ was observed. The same result with the molecular ion of 3-aminothioanisole was enhanced, while the same phenomenon was not obvious in the EI-MS spectra of 2- or 4-aminothioanisole. To explain the fragmentation, we proposed a mechanism that involved the hydrogen transfer-induced S–C rearrangement with 3 pathways. Substituent effect results, deuterium-labelled experiments and density functional theory (DFT) calculations also confirmed the proposed mechanism.

中文翻译：

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具有位点特异性的苯硫醚衍生物分子离子中氢转移诱导的 S-C 重排

在本研究中，使用电子电离质谱 (EI-MS) 研究了茴香硫醚衍生物分子离子的气相碎裂。在 EI-MS 谱图中，观察到了特征碎片离子 [M - SH] ⁺。与3-氨基苯硫醚的分子离子相同的结果得到增强，而在2-或4-氨基苯硫醚的EI-MS谱中相同的现象不明显。为了解释断裂，我们提出了一种机制，涉及氢转移诱导的 S-C 重排，具有 3 条途径。取代基效应结果、氘标记实验和密度泛函理论 (DFT) 计算也证实了所提出的机制。