Rotamers and isomers in the fulgide series. Part 1. Stereochemistry and conformational analysis of bis-(3,4-dimethoxybenzylidene)succinic anhydrides by X-ray crystallography and molecular mechanics
作者:Jan C. A. Boeyens、Louis Denner、Guido W. Perold
DOI:10.1039/p29880001749
日期:——
two forms, the Z,Z-isomer and the arylnaphthalene derivative. X-Ray structures of these crystalline forms are reported. The conformations of the other rotamers were simulated by molecular mechanics, using an empirical force-field based on the observed structure of the symmetrical E,E-rotamer, described here. The aromatic rings of the E,E-isomers are eclipsed and under severe strain, which inhibits free
双-(3,4-二甲氧基亚苄基)琥珀酸酐的构象分析表明,除了Z,Z-异构体外,该二芳基富马特的E,E-异构体还以三种不同的相对自由地可相互转化的手性旋转异构体及其对映异构体的形式出现。的ë,ê异构体经历容易脱氢以形成arylnaphthalene衍生物。获得具有两种形式的对称的E,E-旋转异构体Z,Z-异构体和芳基萘衍生物的晶体。X报道了这些结晶形式的射线结构。其他旋转异构体的构型是通过分子力学模拟的,使用的是经验力场,该力场基于此处描述的对称E,E-旋转异构体的观察结构。E,E-异构体的芳环会黯然失色,并处于严重的应变之下,这会抑制自由旋转。堆积能量仅促进可能的E,E-旋转异构体之一的结晶,并且对甲氧基取代基的取向具有显著作用。