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    • 1. 发明授权
    • Oxazolinium salts and method of preparation
    • 唑啉盐及其制备方法
    • US4237304A
    • 1980-12-02
    • US955039
    • 1978-10-26
    • William DowdRichard C. KraussEdward R. Freiter
    • William DowdRichard C. KraussEdward R. Freiter
    • C07D263/10C07D263/12C07D263/14
    • C07D263/10
    • 1-Aryl-1-hydroxy-2-methylaminopropanes are rearranged from the erythro isomer to the threo isomer by the process of (1) forming the O,N-diacyl derivative of the arylpropanolamine; (2) reacting the product of step (1) with an anhydrous or substantially anhydrous protic acid (thereby forming a novel oxazolinium salt); and (3) reacting the oxazolinium salt from step (2) with an aqueous protic acid. The threo isomer of the arylpropanolamine is thus produced as an amine/acid salt. This salt can be further purified, if desired, by neutralizing the acid/amine salt with caustic isolating the free amine and reprotonating the free base in isopropanol with, for example, anhydrous HCl. This process is particularly applicable to manufacture of d-pseudoephedrine from 1-ephedrine.
    • 通过(1)形成芳基丙醇胺的O,N-二酰基衍生物的方法将1-芳基-1-羟基-2-甲基氨基丙烷从红异构体重排为苏式异构体; (2)使步骤(1)的产物与无水或基本上无水的质子酸(从而形成新的恶唑啉盐)反应; 和(3)使来自步骤(2)的恶唑啉盐与水性质子酸反应。 因此,芳基丙醇胺的苏式异构体以胺/酸盐的形式制备。 如果需要,该盐可以通过用分离游离胺的苛性碱中和酸/胺盐进一步纯化,并用例如无水HCl将异丙醇中的游离碱重新分配。 该方法特别适用于从1-麻黄素制备d-伪麻黄素。