New Chiral Kemp's Acid Diamides for Chiral Amine Recognition by ~1H NMR

摘要

Two Kemp's acid diamides were synthesized and applied to chiral amine recognition using ~1H NMR analysis. One derivative based on 1-(1-naphthyl)ethylamine had good chiral recognition of six amines and was useful to determine the optical purity for three amines, i.e., methylbenzylamine, 1-(1-naphthyl)ethylamine and 1-phenylpropylamine, however, the cyclohexy-lethylamine derivative showed little discrimination for the amines studied. Together with the results for alkylamines, it was shown that aromatic structure was important for aromatic shielding anisotropy and pi-pi interactions between host and guest. The structure of the 1-(1-naphthyl)ethylamine derivative in solution was also considered based on ~1H NMR data and computer simulation.