Structural Analysis with NMR Chemical Shift calculation

溶液中的构象分析是了解有机化合物物理化学性质的必要手段。虽然核磁共振技术如距离相关的nOe和扭转相关的^3JHH耦合常数被广泛使用，但它并不总是令人满意。我们最近开发了利用极性官能团取代基诱导位移（SIS）的化学位移模拟。这种模拟方法可以计算极性取代基附近质子的诱导位移。为了扩大这种独特的构象分析方法的适用性，我们成功地获得了有机化合物中普遍存在的仲胺基（C-NH-C）的SIS参数。采用类似的方法利用雄甾酮骨架获得了萘环的磁各向异性。取代位移的成功再现清楚地表明，分子动力学与化学位移模拟方法的结合对柔性分子动态结构构象分析的发展起着重要作用。采用分子动力学和化学位移模拟相结合的方法，成功地分析了包合物的动态结构。

Conformational analysis in solution is indispensable for understanding of physical and chemical properties of organic compound. While NMR techniques such as distance-dependent nOe and torsion-dependent ^3JHH coupling constants were used extensively, it is not always satisfactory. We have recently developed chemical shift simulation, which utilizes the substituent induced shifts (SIS) of polar functional groups. This simulation method can calculate the induced shift of a near-by proton from a polar substituent. To widen the applicability of this unique method for conformational analysis, we have succeeded to obtain the SIS parameters of the secondary amine group (C-NH-C) which is ubiquitous in organic compounds. Similar procedure using androstanone skeletons was applied to obtain the magnetic anisotropy of naphthalene ring. The successful reproduction of the substitution induced shifts clearly indicates that the combination of the molecular dynamics and the chemical shift simulation method play an important role in the development of the conformational analysis of the dynamic structure of the flexible molecules. The dynamic structure of inclusion complexes was also successfully analyzed by the combination of the molecular dynamics and the chemical shift simulation.