Controlling the Outcome of an <i>N</i>-Alkylation Reaction by Using <i>N</i>-Oxide Functional Groups
作者:Russell J. Pearson、Kathryn M. Evans、Alexandra M. Z. Slawin、Douglas Philp、Nicholas J. Westwood
DOI:10.1021/jo0503106
日期:2005.6.1
Covalent modifiers of proteins are of importance in chemical proteomics, an emerging chemical technology used to assign protein function. In this study, high-field H-1 NMR techniques were used to analyze the reaction of the bioactive compound, 2,3-bis(bromomethyl)quinoxaline 1,4-dioxide, with amines (a model system for proteins containing nitrogen-based nucleophiles). Unexpectedly, the results show that a double nucleophilic substitution reaction involving 2 equiv of the amine is preferred to an intramolecular cyclization pathway. A direct comparison with the reaction carried out on a substrate lacking the N-oxide functional groups is also provided. X-ray crystal structures and computational studies are used to rationalize the observed differences in reactivity between the two systems.