Knapp F F, Schroepfer G J
Chem Phys Lipids. 1976 Nov;17(4):466-500. doi: 10.1016/0009-3084(76)90048-7.
The electron impact ionization of C-4-alkylated cholest-5-en-3beta-hydroxysterols has been investigated. The mass spectra of the C-4-alkylated cholesterols contain a number of ions in the high mass region for which analogous ions are not found in the spectrum of cholesterol. Detailed studies of the composition and origin of these ions have been made by high resolution mass spectrometry and analysis of metastable ions. In addition, a large number of isotopically (deuterium and 18O) substituted C-4-alkylated analogues have been prepared to assist in the interpretation of the spectra. The combined results indicate the occurrence of a number of very complex and unusual electron ionization induced fragmentations. Most notable of the findings reported herein concerns the demonstration of the formation of an ion involving loss of the elements of ring A with an intramolecular shift of the oxygen and hydrogen atoms of the hydroxyl function to the charge-retaining species.
对C-4-烷基化胆甾-5-烯-3β-羟基甾醇的电子碰撞电离进行了研究。C-4-烷基化胆固醇的质谱在高质量区域包含许多离子，而在胆固醇的质谱中未发现类似离子。通过高分辨率质谱和亚稳离子分析对这些离子的组成和来源进行了详细研究。此外，还制备了大量同位素（氘和18O）取代的C-4-烷基化类似物，以协助解释光谱。综合结果表明发生了许多非常复杂和不寻常的电子电离诱导碎片化。本文报道的最显著发现涉及证明形成了一种离子，该离子涉及A环元素的损失，同时羟基官能团的氧和氢原子发生分子内转移至电荷保留物种。
