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。
An easy, four-step access to naturally occurring (±)-(E)-2-hexylidene-3-methylsuccinic acid (piliformic acid, 1) with 49% overall yield has been described via Wittig reaction of methyl(triphenylphosphoranylidene)succinimide 7 with hexanal followed by acid-induced hydrolysis of the formed succinimide derivatives (E)-8 plus (Z)-9.
Cyanuric chloride: decent dehydrating agent for an exclusive and efficient synthesis of kinetically controlled isomaleimides
作者:Kishan P. Haval、Santosh B. Mhaske、Narshinha P. Argade
DOI:10.1016/j.tet.2005.10.027
日期:2006.1
Starting from maleanitic and maleamic acids, a facile general approach to kinetically controlled isomaleimides has been described for the first time using cyanuric chloride as a dehydrating agent with 85-98% yields. The effect of a variety of substituents present on the aromatic ring in amine and maleic anhydride moiety, on these kinetic/thermodynamic dehydration processes of anilic acids has been also described. Under the same set of reaction conditions the phthalanilic acid gave kinetically controlled product, isoplitalimide in 91% yield, while the corresponding succinanilic acid furnished the thermodynamically more stable succinimide in high yield. (c) 2005 Elsevier Ltd. All rights reserved.