Improved Large-Scale Liquid-Phase Synthesis and High-Temperature NMR Characterization of Short (F-)PNAs
作者:Tobias A. Plöger、Günter von Kiedrowski
DOI:10.1002/hlca.201100243
日期:2011.11
unpaired PNA n‐mers exist in a mixture of 2n conformers undergoing slow exchange and leading to complicated NMR spectra. Structure analysis was improved by recording 1H‐ and 13C‐NMR spectra at elevated temperatures above the coalescence point. Fully protected backbone derivatives show sharp resonances where expected, and spectra of protected PNAs are remarkably simplified, thereby allowing an interpretation
我们报告了F-PNA三聚体10和PNA三聚体11的大规模合成。关键的改进是(2,4-二氟-5-甲基苯基)乙酸的简便两步合成(2)。相应的F-PNA低聚物10的水溶性是通过合成溶解度增强剂5a来实现的,该增强剂具有两个带正电且仅由PNA固有的结构元素组成。受保护且未配对的PNA n单体存在于2 n个构象异构体的混合物中,它们经历缓慢交换并导致复杂的NMR光谱。通过记录1 H-和13改进了结构分析高于聚结点的高温下的C-NMR谱图。完全受保护的主链衍生物在预期的地方显示出剧烈的共振,并且受保护的PNA的光谱显着简化,从而首次得以解释。修剪器10和11都被视为基于PNA的自我复制系统的构建块。