Chiral α-Aminoxy Acid/Achiral Cyclopropane α-Aminoxy Acid Unit as a Building Block for Constructing the α N−O Helix
作者:Dan Yang、Xiao-Wei Chang、Dan-Wei Zhang、Ze-Feng Jiang、Ke-Sheng Song、Yu-Hui Zhang、Nian-Yong Zhu、Lin-Hong Weng、Min-Qin Chen
DOI:10.1021/jo100810m
日期:2010.7.16
revealed that the biased handedness of α N−O turn found in OAcc residue depends on its preceding chiral residue. It was then found that the helical conformation was destroyed in the case of oligopeptides 6 and 7 [OAA-(OAcc)n, n = 2, 3]. The crystal structure of tripeptide 8 (iPrCO-d-OVal-OAcc-d-OVal-NHiBu) further disclosed the helical structure formed by three consecutive homochiral α N−O turns. This study
单体1从非手性的1-(氨氧基)环丙烷羧酸(OACC)和寡肽衍生的2 - 9由手性α氨氧基酸的和如OACC非手性α氨氧基酸的合成和它们的结构特征。八元环分子内氢键,即αN-O圈,在相邻残基之间形成,与它们的手性无关。但是,螺旋的形成是序列依赖性的。在N末端带有手性α-氨基酸(d -OAA)的二肽2和在C末端具有非手性OAcc的二肽优先采用右旋1.8 8螺旋结构,但是二肽3(OAcc- d-OAA)没有。理论计算结果与实验结果吻合良好,表明在OAcc残基中发现的αN-O转弯的偏向性取决于其先前的手性残基。然后发现在寡肽6和7 [OAA-(OAcc)n,n= 2,3]的情况下,螺旋构象被破坏。三肽8(i PrCO- d -OVal-OAcc - d -OVal-NH i的晶体结构Bu)进一步公开了由三个连续的同手性αN-O匝形成的螺旋结构。这项研究发现了非手性氨基氧酸残基(如OAcc单元)是一种