• 主题
高级搜索  >
历史搜索 清空历史
首页> 外文期刊>Chemistry: A European journal >Gaining Insight Into Reactivity Differences Between Malonic Acid Half Thioesters (MAHT) and Malonic Acid Half Oxyesters (MAHO)
【24h】

Gaining Insight Into Reactivity Differences Between Malonic Acid Half Thioesters (MAHT) and Malonic Acid Half Oxyesters (MAHO)

机译：获得阳性酸半硫酸盐（Maht）和丙酸半钠（MAHO）之间的反应性差异的洞察

获取原文
获取原文并翻译 | 示例
           
页面导航
  • 摘要
  • 著录项
  • 相似文献
  • 相关主题

摘要

An efficient two-step synthesis of structurally and functionally diverse thiophenol- and (cyclo)alkyl-derived malonic acid half thioesters (MAHTs) and phenol-derived malonic acid half oxyesters (MAHOs) has been achieved using cheap, readily available and easily handled starting materials. The synthesis of the MAHTs and MAHOs (the majority of which have not been previously reported) is readily scalable to afford gram quantities of product. In a hydrogen→deuterium exchange, an interesting stereoelectronic effect was observed when different aryl groups were incorporated. Significant changes in the rates of hydrogen!deuterium exchange and levels of isotope incorporation were observed. By way of example, using [~2H]methanol and 4-bromophenolderived MAHO afforded only 14% [~2H]-incorporation (9 min, k=31) whereas the corresponding 4-bromothiophenol-derived MAHT afforded 97% [~2H]-incorporation (9 min, k=208). In a benchmark procedure and comprehensive DFT study, 54 ester and thioester configurations and conformations were characterized. In the MAHT series, a sulfur-containing molecular orbital provides a path for increased delocalisation of electron density into the enol that is unavailable in MAHOs. This facilitates keto-enol tautomerisation and consequently enhances the rate and percentage of hydrogen→deuterium exchange.
机译：使用廉价，易于获得和容易处理的开始，实现了在结构上和功能性不同的噻吩醇 - 和（环偶）烷基衍生的半硫酸半硫酸（MAHOL）和酚类衍生半羟酸半钠（MAHOL）和苯酚衍生的丙二酸半氧酸（Mahol）的两步合成。材料。 MaHTS和MAHOS的合成（其中大多数尚未报道）是易于扩展的，以提供克数量的产品。在氢气→氘交换中，当掺入不同的芳基时，观察到一个有趣的立体电极效应。氢气率的显着变化！观察到氘交换和同位素掺入水平。举例来说，使用仅14％[〜2H] - 丙杂化（9分钟，k = 31），使用仅提供14％[〜2H] - 丙二醇（9分钟，K = 31），而相应的4-溴苯酚衍生的MaHT为97％[〜2h] - 森林（9分钟，K = 208）。在基准程序和综合DFT研究中，特征在于54个酯和祖联配置和构象。在MAHT系列中，含硫的分子轨道提供了一种用于将电子密度的逐渐增加的路径增加到MAHOS中不可用的烯醇。这有利于酮 - 烯醇跳跃，从而提高氢气→氘交换的速率和百分比。

著录项

相似文献

  • 外文文献
  • 专利
获取原文

客服邮箱：kefu@zhangqiaokeyan.com

京公网安备：11010802029741号 ICP备案号：京ICP备15016152号-6 六维联合信息科技 (北京) 有限公司©版权所有

  • 客服微信

  • 服务号