The enantiomeric recognition of chiral organic ammonium salts by chiral monoaza-15-crown-5 ether derivatives

Novel chiral monoaza-15-crown-5 ether derivatives 1 and 2 were prepared frorn L-phenylalaninol and L-leucinol, respectively. The effect of the substituent at the stereogenic center on chiral recognition and enantioselectivity were investigated. Binding constant (K), free-energy changes (-DeltaG(0)), enthalpy change (DeltaH), and entropy change (DeltaS) values were determined with enantiomers of organic ammonium salts by a titration UV-vis method in CHCl3. (C) 2004 Elsevier Ltd. All rights reserved.