Synthesis and X-ray crystal structures of chiral, nonracemic 5,6-dihydro-4H-1,3,4-oxadiazines
作者:Shawn R. Hitchcock、Melissa A. Dean、Christopher J. Kelley、Kate L. Edler、Gregory M. Ferrence
DOI:10.1002/jhet.402
日期:——
A series of chiral, nonracemic oxadiazines have been prepared from (1R,2S)‐ephedrine, (1R,2S)‐norephedrine, and L‐phenylalaninol. The synthesis of the Ephedra‐based oxadiazines was accomplished by a process of N‐nitrosation, reduction, acylation, and acid‐catalyzed cyclization. The trans‐ and cis‐diastereomeric oxadiazines derived from (1R,2S)‐ephedrine were analyzed by 1H NMR spectroscopy and by single
已从(1 R,2 S)-麻黄碱,(1 R,2 S)-去氧麻黄碱和L-苯丙氨醇制备了一系列手性,非外消旋的恶二嗪。基于麻黄的恶二嗪的合成是通过N亚硝化,还原,酰化和酸催化的环化过程完成的。的反式-和CIS衍生自-diastereomeric恶二嗪(1 - [R,2小号) -麻黄碱通过分析1个H NMR光谱和通过单晶X射线晶体学分析。(1 R,2 S)-基于去甲氧麻黄碱的恶二嗪是基于1 H NMR光谱和类似于基于(1 R,2 S)-麻黄碱的恶二嗪的X射线晶体结构进行分配的。另外,以L-苯丙氨醇为模板,制备了一系列在N 4-氮处被异丙基取代的恶二嗪。这是通过将L-苯丙氨醇与丙酮进行还原性烷基化并随后形成酰肼来实现的。这些酰肼与甲磺酰氯通过碱介导的环化反应生成相应的恶二嗪。J.杂环化学。(2010)。