N-Linked Peptidocalix[4]arene Bisureas as Enantioselective Receptors for Amino Acid Derivatives

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• 作者：Anton V. Yakovenko ; Vyacheslav I. Boyko ; Vitaly I. Kalchenko ; Laura Baldini ; Alessandro Casnati ; Francesco Sansone ; Rocco Ungaro
• 刊名：Journal of Organic Chemistry
• 出版年：2007
• 出版时间：April 27, 2007
• 年：2007
• 卷：72
• 期：9
• 页码：3223 - 3231
• 全文大小：338K
• 年卷期：v.72,no.9(April 27, 2007)
• ISSN：1520-6904

文摘

D=jo062410xn00001>Bisurea calix[4]arenes 1 and 2 possessing L-amino acid moieties at the lower rim were synthesized byreaction of the methyl esters of glycine, L-alanine, or L-isoleucine with the appropriate isocyanate (12 or13), obtained with a safe and efficient Curtius rearrangement from the corresponding carboxylic acidderivatives. The conformational properties of the ligands 1 and 2 were investigated by means of a combinedNMR and molecular modeling study which evidences that they are deeply influenced by strongintramolecular H-bonds between the urea NH groups and the vicinal phenolic oxygen atoms or the oppositeurea C=O group. Complexation studies performed by ESI-MS and NMR spectroscopy in acetone solutionshow that the binding ability of these bisurea hosts decreases by increasing the side chain size of theamino acid. Host 2b has a remarkable binding ability for the N-acetyl-D-phenylalaninate anion with aninteresting enantioselectivity (/ = 4.14), which is explained on the basis of a three-pointinteraction mode of binding.