A convenient, NMR-based method for the analysis of diastereomeric mixtures of pseudoephedrine amides
A convenient, NMR-based method for the analysis of diastereomeric mixtures of pseudoephedrine amides
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DOI：
10.1021/ol0628762
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发表时间：
2007-01-18
期刊：
影响因子：
5.2
通讯作者：
Myers, Andrew G.
中科院分区：
文献类型：
--
作者：
Chain, William J.;Myers, Andrew G.
伪麻黄碱和麻黄碱的酰胺在三氟甲磺酸酐-吡啶存在下发生高度立体特异性的反向环化反应，形成4，5-二氢-3，4-二甲基-5-苯基-1，3-恶唑鎓三氟甲磺酸盐衍生物。未纯化的反应产物的1H-1 NMR谱是非常干净的，具有尖锐的、明确的峰，并且允许快速评估起始酰胺的非对映体纯度。
Amides of pseudoephedrine and ephedrine are shown to undergo highly stereospecific, invertive cyclization to form 4,5-dihydro-3,4-dimethyl-5-phenyl-1,3-oxazolium triflate derivatives in the presence of triflic anhydride-pyridine. H-1 NMR spectra of the unpurified reaction products are remarkably clean, with sharp, well-defined peaks, and allow for rapid assessment of the diastereomeric purities of the starting amides.