Cody V
Endocr Res Commun. 1982;9(1):55-65. doi: 10.1080/07435808209045753.
It has been suggested that the oxygen bridge linking the two iodophenyl rings of the thyroid hormones at an angle of 120 degrees promotes electron transfer between the rings or establishes the proper stereochemical relationship between the rings. To determine the effects of oxygen bridge substitution on conformation, an analysis of the X-ray crystal structures of a number of oxygen bridge analogues (NH, CO, CHOH, S) was undertaken and the results compared with the thyroid hormone structures. The 3,5-iodine substituents cause the two phenyl rings to adopt a skewed or twist-skewed conformation. The phenyl rings of all bridge substituted analogues can adopt these hormone conformations. There is a correlation between the bridging bond length and the bridging angle that tends to keep the overall diphenyl ring conformation constant. The results of sulfur bridge substitution have further structural implications with regard to the design of novel hormone analogues.
有人提出，以120度角连接甲状腺激素两个碘代苯环的氧桥促进了环之间的电子转移，或建立了环之间适当的立体化学关系。为了确定氧桥取代对构象的影响，对一些氧桥类似物（NH、CO、CHOH、S）的X射线晶体结构进行了分析，并将结果与甲状腺激素结构进行了比较。3,5-碘取代基使两个苯环呈现扭曲或扭歪构象。所有桥取代类似物的苯环都可以呈现这些激素构象。桥键长度和桥角之间存在相关性，这倾向于使整个二苯环构象保持恒定。硫桥取代的结果对于新型激素类似物的设计具有进一步的结构意义。
