拟除虫菊酯类农药的NMR研究Ⅰ.α-对取代苯基异戊酸及其类似化合物的手性和前手性NMR研究

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¹³C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。

NMR STUDIES ON SYNTHETIC PESTICIDES I. NMR STUDIES ON CHIRALITY AND PROCHIALITY OF ( P-CI-PHENYL ) ISOAMYL ACID AND ITS ANALOQUES

α(p-cl-phcnyl) isoamyl acid is an important intermediate of synthetic pyr-ethroid. There are a chiral center and two prochiral methyl groups iu its structure. In order to understand the co-relation between structure and bioactivily, one must give a detailed observation on its stuclural specifications. Our work included the separation of ¹H and ¹³C signals of the enanfiomers with chiral LSR Eu (hfbc)₃ and LSR Eu (fod)₃, assignments of the diastereotopic methyl groups and the corelation between the magnitude of the anisochrony produced by the methyl groups and neighbor substitutes. Experimenls coincide with the calculation results from a simplified model.