Abstract

A new synthetic approach to fused azepines was demonstrated on an example of the synthesis of 2-methyl-2,3,4,5-tetrahydro-1H-[1]benzothieno[2,3-c]azepine. The key stage of the synthesis is the formation of the azepine ring under the Eschweiler–Clark reaction conditions. The Gibbs energy of activation for the inversion of the azepine ring was determined by dynamic ¹H NMR spectroscopy. Molecular modeling of the structure and estimation of the ¹H and ¹³C NMR chemical shifts were performed for 2-methyl-2,3,4,5-tetrahydro-1H-[1]-benzothieno[2,3-c]azepine. The magnetic shielding tensors were calculated by the standard GIAO method using the B3LYP/6-31G(d,p)-optimized molecular geometry parameters. The solvent effect was taken into account in the PCM approximation. The calculated ¹H and ¹³C NMR chemical shifts of 2-methyl-2,3,4,5-tetrahydro-1H-[1]-benzothieno[2,3-c]azepine are in good agreement with the experimental values observed in the spectra of its DMSO-d₆ solution.

中文翻译：

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2-甲基-2,3,4,5-四氢-1 H-[1]苯并噻吩并[2,3-c] a庚因的合成，NMR光谱和分子模型

摘要

在合成2-甲基-2,3,4,5-四氢-1 H- [1]苯并噻吩并[2,3- c ]氮杂example的一个实例上证明了一种新的融合a庚因的合成方法。合成的关键阶段是在Eschweiler-Clark反应条件下形成氮杂环丁烷环。通过动态¹ H NMR光谱确定用于氮杂环庚烷环反转的吉布斯活化能。对2-甲基-2,3,4,5-四氢-1 H- [1]-苯并噻吩并[2,3- c ]进行结构的分子建模和¹ H和¹³ C NMR化学位移的估计] a 使用B3LYP / 6-31G（d，p）优化的分子几何参数，通过标准GIAO方法计算出磁屏蔽张量。在PCM近似中考虑了溶剂效应。计算出的2-甲基-2,3,4,5-四氢-1 H- [1]-苯并噻吩并[2,3- c ] a庚因的¹ H和¹³ C NMR化学位移与观察到的实验值非常吻合在其DMSO- d ₆溶液的光谱中。