Nonplanar Tertiary Amides in Rigid Chiral Tricyclic Dilactams. Peptide Group Distortions and Vibrational Optical Activity
作者:Markéta Pazderková、Václav Profant、Jana Hodačová、Jaroslav Šebestík、Tomáš Pazderka、Pavlína Novotná、Marie Urbanová、Martin Šafařík、Miloš Buděšínský、Miloš Tichý、Lucie Bednárová、Vladimír Baumruk、Petr Maloň
DOI:10.1021/jp405226k
日期:2013.8.22
vibrational optical activity (VOA) spectra of tricyclic spirodilactams 5,8-diazatricyclo[6,3,0,01,5]undecan-4,9-dione (I) and its 6,6′,7,7′-tetradeuterio derivative (II). These rigid molecules constrain amide groups to nonplanar geometries with twisted pyramidal arrangements of bonds to amide nitrogen atoms. We have collected a full range vibrational circular dichroism (VCD) and Raman optical activity (ROA)
我们研究三环螺二内酰胺5,8-二氮杂三环[6,3,0,0 1,5的振动光学活性(VOA)光谱中的酰胺非平面性] undecan-4,9-二酮(I)及其6,6',7,7'-四氘代衍生物(II)。这些刚性分子将酰胺基团限制为具有与酰胺氮原子键合的扭曲锥体排列的非平面几何形状。我们已经收集了完整的振动圆二色性(VCD)和拉曼光学活性(ROA)光谱,包括C–H和C–D拉伸振动的信号。我们报告了正常模式分析,并比较了实验VCD和ROA的计算结果。数据提供了带间分配,并为评估受约束的非平面叔酰胺基团和刚性手性骨架的作用提供了可能性。非平面性显示为单符号VCD和ROA酰胺I信号,盛行预期由酰胺-酰胺相互作用产生的expected联。酰胺-酰胺偶联作用占酰胺II(主要是C'–N拉伸,由于不存在N–H键而在叔酰胺中进行了修饰)转变(VCD中的强对联,无显着的ROA),可能是由于酰胺氮原子非常接近所致。在较低