Electron ionization fragmentations of some N‐substituted 2‐N‐methylimino‐4,5‐tetramethyleneperhydro‐3, 1‐oxazines and related thiazines
Electron ionization fragmentations of some N‐substituted 2‐N‐methylimino‐4,5‐tetramethyleneperhydro‐3, 1‐oxazines and related thiazines
复制标题
一些N-取代的2-N-甲基亚氨基-4,5-四亚甲基过氢-3, 1-恶嗪和相关噻嗪的电子电离断裂
DOI：
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发表时间：
1991
期刊：
影响因子：
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通讯作者：
P. Vainiotalo
中科院分区：
文献类型：
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作者：
K. Pihlaja;S. Liukko;F. Fülöp;G. Bernáth;P. Vainiotalo
用亚稳态离子分析和精确质量测量研究了6个2-N-甲基亚氨基过氢-3，1-恶嗪和6个相关的噻嗪类化合物的70 eV电子电离质谱图。对于未被取代的化合物，可以合理地以相对于环氮原子的简单α裂解开始的分解占主导地位。这些反应中的许多伴随着氢原子转移到失去的中性碎片。N-取代促进了更广泛的氢迁移，氢原子被转移到分子的杂环部分。只有甲基取代的化合物表现出显著的立体化学特异性，从而允许异构体的分化。
The 70 eV electron ionization mass spectra of six cyclohexane fused 2-N-methyliminoperhydro-3,1-oxazines and six related thiazines were recorded and their fragmentation behaviour studied by metastable-ion analysis and exact mass measurement. For the unsubstituted compounds, decompositions which can be rationalized to start as a simple α-cleavages with respect to the ring nitrogen atom were dominant. Many of these reactions were accompanied by a hydrogen-atom transfer to the neutral fragment lost. N-substitution prompted more extensive hydrogen migrations to take place, where hydrogen atoms were transferred to the heterocyclic part of the molecule. Only methyl-substituted compounds showed remarkable sterochemical specificity, thus allowing isomeric differentiation to take place.