Gas-Phase Intercluster Thiyl-Radical Induced C–H Bond Homolysis Selectively Forms Sugar C2-Radical Cations of Methyl D-Glucopyranoside: Isotopic Labeling Studies and Cleavage Reactions
作者:Sandra Osburn、Gaetano Speciale、Spencer J. Williams、Richard A. J. O’Hair
DOI:10.1007/s13361-017-1667-2
日期:2017.7.1
exchangeable OH and NH protons with deuterons reveals that the sugar radical cation is formed in a process involving abstraction of a hydrogen atom from a C-H bond of the sugar coupled with proton transfer to the sugar, to form [M - H• + D+]. Investigation of this process using individual C-D labeled sugars reveals that the main site of H/D abstraction is the C2 position, since only the C2-deuterium
一组甲基D-吡喃葡萄糖苷的同位素异构体与多级质谱实验结合使用,以确定通过最近开发的“生物启发”方法形成的糖自由基阳离子的自由基位点和裂解反应。在CID(MS2)的第一阶段,糖和S-亚硝基半胱胺[H3NCH2CH2SNO + M] +之间的质子化非共价复合物的碰撞诱导解离(CID)通过键均解释放硫代自由基,得到非共价自由基阳离子,[H3NCH2CH2S•+ M] +。该自由基阳离子复合物的CID(MS3)导致非共价复合物解离,生成糖自由基阳离子。用氘核取代所有可交换的OH和NH质子表明,糖自由基阳离子是在一个过程中形成的,该过程涉及从糖的CH键中夺取氢原子,然后将质子转移到糖中,从而形成[M-H•+ D +]。使用单个CD标记的糖对此过程进行的研究表明,H / D提取的主要位点是C2位置,因为只有C2氘标记的糖会产生占主导地位的[M-D•+ H +]产物离子。通过另一阶段的CID(MS4)研究了二糖糖基阳离子[M-H•+