Synthesis, Spectroscopic Characterization, and Structural Modeling of Chiral Calix[4]Arene–Amino Acid Conjugates in <i>Cone</i> Conformation

ABSTRACT This study reports the synthesis and structural properties of four new amino acid derivatives of calix[4]arene ( 7a‐d ), which have been synthesized from the condensation of bis(chloro formylmethoxy)calix[4]arene with respective amino acid esters ( L ‐alanine methyl ester, L ‐phenyl alanine ethyl ester, L ‐aspartic acid diethyl ester, and L ‐cysteine methyl ester). Synthetic routes were developed to link amino acid esters at the lower rim of calix[4]arenes blocked in the cone conformation. The amino acid derivative of calix[4]arene ( 7a ) was obtained using the cooled solution of L ‐alanine methyl ester ( 6a ) with triethylamine in dry CH 2 Cl 2 . The reaction of these compounds ( 6a‐d ) with calix[4]arene gave the corresponding amino acid derivatives of calix[4]arene ( 7a‐d ). The structural properties of all calix[4]arenes containing amino acids are characterized by ATR‐IR and 1 H‐NMR spectroscopic techniques, as well as molecular mechanics (MM) and molecular dynamics (MD) simulations.