Xu Peng-Xiang, Hu An-Fu, Hu Dan, Gao Xiang, Zhao Yu-Fen
Department of Chemistry, Xiamen University, Xiamen 361005, People's Republic of China.
Rapid Commun Mass Spectrom. 2008 Oct;22(19):2977-83. doi: 10.1002/rcm.3696.
Several O-2',3'-isopropylideneuridine-O-5'-phosphoramidate monoesters were synthesized and analyzed by negative ion electrospray ionization tandem mass spectrometry (ESI-MS(n)). Two kinds of novel rearrangement reactions were observed due to the difference in the amino acid in the nucleoside phosphoramidate monoesters, and possible mechanisms were proposed. One involves a five-membered cyclic transition state. The other is formation of a stable five-membered ring intermediate by Michael addition. Results were confirmed by tandem mass spectrometry and isotopically labeled hydrogen atoms. Furthermore, the internal hydrogen exchange between active hydrogen and methyl acrylate in the heated capillary of the mass spectrometer was found. The characteristic fragmentation behavior in ESI-MS may be used to monitor this kind of compounds in the biological metabolism.
合成了几种O-2',3'-异亚丙基尿苷-O-5'-磷酰胺单酯，并通过负离子电喷雾电离串联质谱（ESI-MS(n)）进行分析。由于核苷磷酰胺单酯中氨基酸的差异，观察到了两种新型重排反应，并提出了可能的机制。一种涉及五元环状过渡态。另一种是通过迈克尔加成形成稳定的五元环中间体。串联质谱和同位素标记氢原子证实了结果。此外，还发现了质谱仪加热毛细管中活性氢与丙烯酸甲酯之间的内部氢交换。ESI-MS中的特征性裂解行为可用于监测生物代谢中的这类化合物。
