Diastereomeric Selective Effects for Growth Inhibition of Synthesized Mini Parallel Double-Stranded Peptides on Escherichia coli and Staphylococcus aureus
Efficient Macrocyclization of U-Turn Preorganized Peptidomimetics: The Role of Intramolecular H-Bond and Solvophobic Effects
作者:Jorge Becerril、Michael Bolte、M. Isabel Burguete、Francisco Galindo、Enrique García-España、Santiago V. Luis、Juan F. Miravet
DOI:10.1021/ja0284759
日期:2003.6.1
acetonitrile to very efficiently yield macrocyclic structures. The cyclization reaction does not require high dilution techniques and seems to be insensitive to the size of the formed macrocycle. The analysis of data obtained by (1)H NMR, single-crystal X-ray diffraction, fluorescence measurements, and molecular mechanics indicate that folded conformations can preorganize the system for an efficient cyclization
源自氨基酸的简单拟肽分子在乙腈中与间位和对位双(溴甲基)苯反应,非常有效地产生大环结构。环化反应不需要高稀释技术,并且似乎对形成的大环的大小不敏感。通过 (1)H NMR、单晶 X 射线衍射、荧光测量和分子力学获得的数据分析表明,折叠构象可以预先组织系统以实现有效的环化。分析了在折叠构象存在下分子内氢键和疏溶剂效应所起的作用。
Chiral bis(amino amides) as chiral solvating agents for enantiomeric excess determination of α-hydroxy and arylpropionic acids
作者:Belén Altava、M. Isabel Burguete、Noèlia Carbó、Jorge Escorihuela、Santiago V. Luis
DOI:10.1016/j.tetasy.2010.05.010
日期:2010.4
A family of bis(amino amides) derived from natural amino acids has been synthesized and tested for the NMR enantiodiscrimination, as chiral solvating agents, for enantiomeric excess determination of some carboxylic acids. Those bis(amino amide) receptors contain different structural modifications and the splitting of the signals of the acids, after addition of the corresponding CSAs, depends on those structural variables. The influence of aminoacid side chain and the nature of the aliphatic spacer are important parameters to obtain good chiral discriminations. The results obtained clearly show the chiral recognition abilities of these bis(amino amide) ligands and suggest their advantageous use as chiral solvating agents for carboxylic acids. The binding between bis(amino amides) and carboxylic acids has been studied by ESI-MS, NMR, DSC, and molecular modeling. The data suggest that enantiodiscrimination involves the formation of an ionic pair after proton transfer from the carboxylic substrate to the bis(amino amides). (C) 2010 Elsevier Ltd. All rights reserved.