Chain William J, Myers Andrew G
Department of Chemistry and Chemical Biology, Harvard University, Cambridge, Massachusetts 02138, USA.
Org Lett. 2007 Jan 18;9(2):355-7. doi: 10.1021/ol0628762.
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. 1H 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. [reaction: see text].
伪麻黄碱和麻黄碱的酰胺在三氟甲磺酸酐-吡啶存在下会发生高度立体专一性的构型翻转环化反应，生成4,5-二氢-3,4-二甲基-5-苯基-1,3-氧杂唑三氟甲磺酸盐衍生物。未纯化的反应产物的1H NMR光谱非常清晰，峰尖锐且明确，可快速评估起始酰胺的非对映体纯度。[反应：见正文]
