已经制备了一系列大环受体,它们含有连接两个氨基酸的联吡啶基团。氨基酸和连接间隔基都发生了变化。使用1 H NMR光谱和X射线晶体学研究了所得大环的结构。L-缬氨酸的使用导致大环的开放构象,其中2-丙基取代基垂直于环的平面定向,使得联吡啶和酰胺基易于与金属或互补底物结合。基于脯氨酸的大环化合物具有扭曲的排列方式,其连接链延伸穿过联吡啶的表面,从而占据了反式构象。已经研究了这些衍生物的金属离子结合性能,并显示仅对具有两个预先配位用于络合的吡啶环的缬氨酸大环发生。这些大环化合物还显示出通过使用氢键供体和连接链中酰胺基团的受体与酚羟基结合。
Bis(amino amides) derived from natural amino acids as chiral receptors for N-protected dicarboxylic amino acids
摘要:
A family of bis(amino amides) derived from natural amino acids has been synthesized and tested for the NMR enantiodiscrimination, as chiral receptors, of some N-protected dicarboxylic amino acids. The influence of the amino acid side chain is an important parameter to obtain good enantiodiscrimination. The binding between bis(amino amides) and N-protected dicarboxylic amino acids has been thoroughly studied by ESI-MS and NMR spectroscopic methods as well as by molecular modeling. (C) 2012 Elsevier Ltd. All rights reserved.