Preparation and Characterization of New Chiral Nitronyl Nitroxides Bearing a Stereogenic Center in the Imidazolyl Framework
作者:Satoshi Shimono、Rui Tamura、Naohiko Ikuma、Tatsuya Takimoto、Naoyuki Kawame、Osamu Tamada、Naoko Sakai、Hiroaki Matsuura、Jun Yamauchi
DOI:10.1021/jo0354443
日期:2004.1.1
synthetic procedure for optically active and racemic α-nitronyl nitroxides (α-NNs) having a stereogenic center at the 4-position of the imidazolyl ring is described. This procedure consists of (1) the synthesis of a dissymmetric vic-dinitro compound by Kornblum reaction, (2) the enantiomeric resolution of the racemate by a diastereomer method for obtaining the optically active sample, (3) the quick reduction
描述了在咪唑基环的4-位具有立体异构中心的旋光和外消旋的α-亚硝基硝基氮氧化物(α-NNs)的合成方法。此过程包括:(1)一个不对称的合成VIC -dinitro化合物由科恩布卢姆反应,(2)外消旋体通过用于获得光学活性样品非对映体方法的对映体拆分,(3)快速还原光学活性的或外消旋VIC -dinitro化合物与双(羟基氨基)用Al / Hg的衍生物,(4)双(羟基氨基)化合物与醛的无溶剂缩合,得到1,3- dihydroxyimidazolidine,和(5)的NaIO 4水溶液对α-NN前体的最终氧化。( - ) - (1光学活性α-神经网络的绝对构型通过用的X射线晶体结构相关分配小号,4 - [R )的光学活性的-camphanic酸酯衍生物VIC -dinitro化合物。通过CD光谱法和蒙特卡罗方法将能量最小化,发现旋光性α-NNs的分子构象在溶液和固态中都折叠。分别通过EPR光谱