Study on the Molecular Recognition of <i>α</i>,<i>α</i>,<i>α</i>,<i>β</i>‐ZnT(<i>o</i>‐BocThr)APP toward Imidazole Derivatives and Amino Acid Esters

Abstract

Abstract Molecular Recognition of α , α , α , β ‐ZnT( o ‐BocThr)APP ( 1) toward a series of imidazole derivatives and amino acid esters was investigated. Association constants were determined in chloroform by means of UV‐Vis titration method. The association constants of 1 with imidazole derivatives are larger than those of 1 with amino acid esters. 1 H NMR spectra were investigated to describe the binding mode of the recognition system, showing that all the protons of the guests were shifted to upfield. The circular dichroism spectra of 1 ‐ L ‐/ D ‐ValOMe showed a split cotton effect in Soret region, while those of 1 ‐ L ‐/ D ‐PheOMe showed no split cotton effect. Molecular modeling was performed to understand chiral recognition on a molecular level. Quantum chemical calculation was carried out based on the stable conformations of these recognition systems, which gave a reasonable explanation for the behavior of molecular recognition. The results indicated that the conformation of 1 ‐ D ‐ValOMe was more stable than that of 1 ‐ L ‐ValOMe.