Enantioselective Recognition for Carboxylic Acids by Novel Chiral Macrocyclic Polyamides Derived from L-/D-tartaric Acid

Abstract

The enantioselectivity of chiral macrocyclic polyamides 1–3 derived from L-/D-tartaric acid was investigated by using ¹H NMR. All the macrocycles exhibited certain chiral recognition towards the enantiomers of the racemic carboxylic acids we had chosen. As a chiral solvating agent, the compound 3 has the excellent enantiomeric discriminating ability for mandelic acids and its derivatives, containing an α-OH at the chiral carbon, while the compound 2 has the best enantioselectivity towards dibenzoyltartaric acid. The molar ratio and the association constants of the compound 3 with each of the enantiomers of some guest molecules were determined by using the Job's plots and a nonlinear leastsquares fitting method, respectively. The effect of the structure of the hosts or guests on the enantioselectivity of the compound 1–3 has been explored.

Keywords:

• Macrocyclic polyamides
• Chiral recognition
• Association constant
• Carboxylic acids

Acknowledgements

We gratefully acknowledge the financial support from the Natural Science Foundation of China (No. 20272045).