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α-对取代苯基异戊酸是合成拟除虫菊酯的重要中间化合物,其结构中有手性—CH—和前手性两个甲基。为了解构效与活性的关系,本文对其结构特点进行了仔细的考察。用手性位移试剂Eu(hfbc)_3和位移试剂Eu(fod)_3分离了对映体的~1H和~(13)C的信号,并作出了一定的解释,为鉴定化合物的光学纯度找出了一种简便的方法。对异丙基上的两个非对映异位甲基作了详细的观察,确定了优势构象,并对其作了标识,实验与由简单模型的计算结果一致。本文认为在对这两个非对映异位甲基信号位移差别大小的影响中,取代基的体积效应起了相当重要的作用。
α-p-Substituted phenyl isovaleric acid is an important intermediate compound for the synthesis of pyrethroids. Its structure contains two methyl groups, chiral -CH- and prochiral. In order to understand the relationship between structure-activity and activity, this paper has carefully examined its structural features. The enantiomers ~ 1H and ~ (13) C signals were separated by the chiral shift reagent Eu (hfbc) _3 and the shift reagent Eu (fod) _3, and some explanations were made to find out the optical purity of the identified compounds A simple way. The two diastereomeric methyl groups on isopropyl were observed in detail. The dominant conformations were identified and identified. The experimental results were in agreement with those calculated by the simple model. In this paper, we consider that the volume effect of substituents plays a very important role in the influence of the size difference of the displacement of the two diastereomeric methyl signals.