Self-Complementary Quadruply Hydrogen-Bonded Duplexes Based on Imide and Urea Units
摘要:
The quadruply hydrogen-bonded duplexes based on an imide-urea structure preorganized by three-center hydrogen bonds were found to associate via bifurcated hydrogen bonds. (1)H NMR dilution experiments revealed the high stability of the homodimer in apolar solvent (K(dim) > 10(5) M(-1) in CDCl(3)) and enhancement of association ability due to electron-withdrawing substituent effects. The ready synthetic availability and adjustable association affinity via electronic effects may render these association units potentially applicable in constructing supramolecular architectures.
作者:Yukun Zhang、Ruikai Cao、Jie Shen、Cadnel S. F. Detchou、Yulong Zhong、Heng Wang、Sheng Zou、Qingfei Huang、Chunxia Lian、Qiwei Wang、Jin Zhu、Bing Gong
DOI:10.1021/acs.orglett.8b00283
日期:2018.3.16
hydrogen-bonding units with lengthened flexible or rigidlinkers generates oligoamide strands that carry new H-bonding sequences and association specificity, leading to H-bonded homo- and heteroduplexes with association constants in the 104 M–1 range in chloroform. Computational and experimental studies indicate that in duplexes with rigidaromaticlinkers the oligoamide strands adopt bent conformations
将基本的氢键单元与加长的柔性或刚性接头连接在一起,可生成带有新的H键序列和缔合特异性的低聚酰胺链,从而在氯仿中产生缔合常数在10 4 M –1范围内的H键均双链和杂双链。计算和实验研究表明,在具有刚性芳族连接基团的双链体中,低聚酰胺链采用弯曲构象,从而允许形成链间H键并容纳引入的芳族内衬,从而提供了一系列新的缔合单元。
Convergent heteroditopic cyclo[6]aramides as macrocyclic ion-pair receptors for constructing [2]pseudorotaxanes
A strategy of using amide groups as the only functionality was developed to construct convergent heteroditopic cyclo[6]aramides that are able to strongly bind dibutylammonium chloride in chloroform (>105 M−1), leading to the formation of [2]pseudorotaxanes.
Reverse Turn Foldamers: An Expanded β-Turn Motif Reinforced by Double Hydrogen Bonds
作者:Quan Tang、Yulong Zhong、Daniel P. Miller、Rui Liu、Eva Zurek、Zhong-Lin Lu、Bing Gong
DOI:10.1021/acs.orglett.9b04547
日期:2020.2.7
Hybrid tetrapeptides sharing a backbone with a central alpha/beta-dipeptide segment flanked by aromatic gamma-amino acid residues fold into the same hairpin conformation with an expanded beta-turn. This hairpin/beta-turn motif is general for accommodating different alpha- and beta-amino acid residues. Replacing glycine with other alpha-amino acid residues has an insignificant influence on or slightly decreases the stabilities of the folded conformations; substituting beta-alanine with other beta-amino acid residues enhances the stabilities of the folded structures.
Functionalized Analogues of an Unnatural Amino Acid that Mimics a Tripeptide β-Strand
作者:Tatyana V. Khasanova、Omid Khakshoor、James S. Nowick
DOI:10.1021/ol8021897
日期:2008.11.20
This paper introduces polar and hydrophobic variants of the unnatural amino acid Hao, which mimics the hydrogen-bonding functionality of one edge of a beta-strand. In these variants, the methyl side chain of Hao is replaced with acidic, basic, and hydrophobic groups. These modifications can impart improved solubility and additional side-chain interactions to peptides containing Hao.