Johnson K R, Ellis G, Toothill C
Clin Chem. 1977 Sep;23(9):1669-78.
New evidence is presented for the mechanism of this reaction, which is used in estimating lipids. The reaction occurs in two stages: (a) Stage 1 evidently involves an oxidation step, forming a specific type of carbonium ion called an alkenyl cation of the general formula R--C+--C==C--R' (previous evidence had indicated that a carbonium ion of general formula R--C+--R' was formed by protonation only.) (b) Stage 2 of the reaction was examined by nuclear magnetic resonance studies and by partition experiments, which have indicated that a vanillin phosphate ester is not formed as previously suggested. Comparative data from other acid-aldehyde reactions indicate that in this reaction 1,1-di(4-hydroxy-3-methoxy phenyl)ethylene ion is formed, a product compatible with the formation of an alkenyl cation at stage 1.
本文提出了用于估算脂质的该反应机制的新证据。该反应分两个阶段进行：(a) 阶段1显然涉及一个氧化步骤，形成一种特定类型的碳正离子，称为通式为R--C+--C==C--R'的烯基阳离子（先前的证据表明，通式为R--C+--R'的碳正离子仅通过质子化形成）。(b) 通过核磁共振研究和分配实验对反应的阶段2进行了研究，结果表明并未如先前所认为的那样形成香草醛磷酸酯。来自其他酸 - 醛反应的比较数据表明，在该反应中形成了1,1 - 二(4 - 羟基 - 3 - 甲氧基苯基)乙烯离子，该产物与阶段1中烯基阳离子的形成相符。
