Key Laboratory of Organosilicon Chemistry and Material Technology, Hangzhou Normal University, Hangzhou, Zhejiang, China.
PLoS One. 2013 May 21;8(5):e63097. doi: 10.1371/journal.pone.0063097. Print 2013.
The gas-phase fragmentation pathways of deprotonated diacylhydrazine derivatives (R1(C = O)-N(t-Bu)NH(C = O)R2, Compounds 1-6) were investigated by the combination of electrospray ionization tandem mass spectrometry (ESI-MS/MS) and theoretical calculations. Upon collisional activation, the deprotonated molecular ions M - H dissociate in two reaction channels, both of which involve intramolecular rearrangement. The main product ion is confirmed to be an anionic acid species, R1-CO2, generated through intramolecular rearrangement of M - H initiated by the nucleophilic attack of the amide O6 on the carbonyl C2 (Path-1). The minor fragment channel (Path-2) involves methylpropene elimination of the precursor ion, followed by a similar nucleophilic displacement reaction to produce another acid anion R2-CO2. Density functional theory calculations at the B3LYP/6-31+G(d,p) level indicate that Path-1 is more favorable than Path-2 for dissociation of the deprotonated halofenozide.
通过电喷雾串联质谱（ESI-MS/MS）和理论计算相结合，研究了脱质子二酰肼衍生物（R1（C=O）-N（t-Bu）NH（C=O）R2，化合物 1-6）的气相碎裂途径。在碰撞激活下，脱质子分子离子[M-H]（-）通过两种反应通道解离，这两种通道都涉及分子内重排。主要产物离子被确认为阴离子酸物种[R1-CO2]（-），通过酰胺 O6对羰基 C2的亲核攻击引发[M-H]（-）的分子内重排生成（Path-1）。次要的片段通道（Path-2）涉及前体离子的甲基丙烯的消除，然后通过类似的亲核取代反应产生另一个酸阴离子[R2-CO2]（-）。B3LYP/6-31+G（d，p）水平的密度泛函理论计算表明，对于脱质子的氟苯醚的解离，Path-1 比 Path-2 更有利。
