Structure-chiroptical properties relationship in oxabicyclic beta-lactam derivatives.

Enantiomer Pub Date : 2002-03-01 DOI:10.1080/10242430212200
J. Frelek, R. Lysek, K. Borsuk, J. Jagodziński, B. Furman, A. Klimek, M. Chmielewski
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引用次数: 15

Abstract

The relationship between molecular structure of 5-dethia-5-oxacephams and clavams and their chiroptical properties was investigated by means of X-ray diffraction analysis, molecular modeling calculations and circular dichroism spectroscopy. It was found that the amide chromophore of the beta-lactam unit in these compounds is nonplanar with nitrogen atom having a pyramidal configuration. It was also found that the helicity of the lactam moiety in investigated oxacephams and clavams is controlled by the absolute configuration at the C-6 and C-5 carbon atom, respectively. Thus, the applicability of helicity rule correlating a positive (negative) torsional angle of the beta-lactam subunit O=C-N-C with a negative (positive) sign of the n-->pi* CE, previously applied to oxacephams, is now extended to clavams.
氧环-内酰胺衍生物的结构-热带性质关系。
采用x射线衍射分析、分子模拟计算和圆二色光谱等方法研究了5-dethia-5-oxacephams和clavams的分子结构与热学性质的关系。发现这些化合物中-内酰胺单元的酰胺发色团是非平面的,氮原子具有锥体构型。研究还发现,所研究的oxacephams和clavams中内酰胺部分的螺旋度分别受C-6和C-5碳原子的绝对构型控制。因此,将β -内酰胺亚基O=C-N-C的正(负)扭转角与n- >pi* CE的负(正)符号相关联的螺旋度规则的适用性,以前应用于oxacephams,现在扩展到clavams。
本文章由计算机程序翻译,如有差异,请以英文原文为准。
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