E-(hydroxyimino)(hydroxymethoxyphosphinyl)acetic acid: Synthesis and pH-dependent fragmentation
作者:Boris A. Kashemirov、Mari Fujimoto、Charles E. McKenna
DOI:10.1016/0040-4039(95)02099-3
日期:1995.12
In contrast to both its parent “troika” acid (E-1, a phosphorylating agent at pH 7 and 25 °C) and its C-methyl isomer (E-2, which is stable at both acidic and neutral pH), (E)-(hydroxyimino)(hydroxymethoxyphosphinyl)acetic acid E-3 was unreactive at pH 7 and 25 °C but at pH 1.5 fragmented to methyl phosphate 10 (15%) and methyl phosphorocyanidate 11 (85%). The minor product is consistent with solvent
与此相反,以它的两个亲本“三方”酸(ë - 1,在pH 7和25℃的磷酸化试剂)和它的C-甲基异构体(ë - 2,其是稳定的,在酸性和中性pH),(È)-(羟基亚氨基)(羟基甲氧基亚膦酰基)乙酸E - 3在pH 7和25℃下不反应,但在pH 1.5下断裂成甲基磷酸酯10(15%)和磷腈基甲基丙烯酸酯11(85%)。次要产物与溶剂磷酸化醛一致,该反应仅在E - 1下观察到。拟议的非磷酸化断裂途径涉及初步È → ž的isomerizalion 3之前至C α -C β裂解。当在乙腈或EtOH中加热E - 3的DCHA +盐(E - 9)时,也检测到双重裂解途径(31 P NMR);除了磷酸化产物(16–19%)外,还形成了11种(81–84%)。的反应ë - 9在回流的EtOH中:吨-BuOH(1:1)显示产物形成低立体选择性(约3:1个的乙基甲基磷酸酯:吨丁基甲基磷酸酯),支持一个游离的磷酸化过程。