Ring Substituent Effects on the Thiol Addition and Hydrolysis Reactions of <i>N</i>-Arylmaleimides
作者:Yingche Chen、Kelvin Tsao、Élise De Francesco、Jeffrey W. Keillor
DOI:10.1021/acs.joc.5b02036
日期:2015.12.18
Maleimide groups are used extensively in bioconjugation reactions, but limited kinetic information is available regarding their thiol addition and hydrolysis reactions. We prepared a series of fluorogenic coumarin maleimide derivatives that differ by the substituent on their maleimide C═C bond. Fluorescence-based kinetic studies of the reaction with β-mercaptoethanol (BME) yielded the second-order rate
马来酰亚胺基团广泛用于生物缀合反应中,但是关于其硫醇加成和水解反应的动力学信息有限。我们制备了一系列的香豆素香豆素马来酰亚胺衍生物,它们的马来酰亚胺C═C键上的取代基不同。与β-巯基乙醇(BME)反应的基于荧光的动力学研究得出了二级速率常数(k 2),而pH值从7到9的pH速率研究得出了碱催化的水解速率常数(k OH)。通过log k 2和log k OH与电子(σ +)和空间(Es norm)C═C取代基的参数。这些相关性表明,硫醇加成反应主要对电子效应敏感,而空间效应在水解反应中占主导地位。这些机理研究为新型生物缀合反应物或荧光标记剂的设计提供了基础。