Rhodium-Catalyzed Asymmetric Construction of Quaternary Carbon Stereocenters: Ligand-Dependent Regiocontrol in the 1,4-Addition to Substituted Maleimides
摘要:
A rhodium-catalyzed asymmetric 1,4-addition of arylboronic acids to substituted maleimides has been described. The regioselectivity in this reaction is controlled by the choice of ligand (dienes or bisphosphines), and 1,4-adducts with a quaternary stereocenter can be obtained with high regio- and enantioselectivity by the use of (R)-H8-binap.
Coumarin-based fluorogenic agents and uses thereof for specific protein labelling
申请人:UNIVERSITY OF OTTAWA
公开号:US09701667B2
公开(公告)日:2017-07-11
There are provided fluorescent labelling agents comprising a dimaleimide core connected to a fluorophore, processes for preparation thereof, and uses thereof for labelling and/or detection of specific protein targets. Fluorescent labelling agents comprising a compound having the structure of Formula I, and salts thereof, are described.
COUMARIN-BASED FLUOROGENIC AGENTS AND USES THEREOF FOR SPECIFIC PROTEIN LABELLING
申请人:UNIVERSITY OF OTTAWA
公开号:US20150316557A1
公开(公告)日:2015-11-05
There are provided fluorescent labelling agents comprising a dimaleimide core connected to a fluorophore, processes for preparation thereof, and uses thereof for labelling and/or detection of specific protein targets. Fluorescent labelling agents comprising a compound having the structure of Formula I, and salts thereof, are described.
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。
Rhodium(III)-Catalyzed [2+2+2] Cyclotrimerization of Diynes with Maleic Anhydrides as Alkyne Equivalents
作者:Takanori Matsuda、Kentaro Suzuki
DOI:10.1002/ejoc.201500252
日期:2015.5
anhydrides function as syntheticequivalents of alkynes in a rhodium(III)-catalyzed reaction with 1,6-diynes to achieve a formal [2+2+2] cyclotrimerization. This approach is useful for reactions involving alkynes with low boiling points or severe ring strain. Hard-to-access [2+2+2] cycloadducts are available through this new cycloaddition strategy by employing easy-to-handle alkyne equivalents.
NMR studies of intramolecular proton exchange in alkylated naphthazarins
作者:Gülnur A. Elöve、J. Herman Schauble
DOI:10.1002/mrc.1260250303
日期:1987.3
Three groups of alkyl‐substituted naphthazarins were studied by 1H and 13C NMR in chloroform‐d at ambient temperature. Preliminary 1H NMRstudies were carried out on selected members of each group at low temperatures (down to –120 °C) in dichloromethane‐d2 solution. Monoalkylnaphthazarins were found to exist predominantly as the 2‐alkyl tautomers (I) and the dimethylalkyl species as the 2,3‐dimethyl‐6‐alkyl