Syntheses of chirally modified thiacalix[4]arenes with enantiomeric aminesand their application to chiral stationary phases for gas chromatography

New chirally modified p-tert-butylthiacalix[4]arenes were synthesized via c onformation- and/or regioselective etherification with ethyl bromoacetate f ollowed by hydrolysis of the ester moiety and then subsequent amidation wit h (S)-1-phenyl-ethylamine or (S)-1-(1-naphthyl)ethylamine. These chiral sel ectors were coated with OV-17 on capillary columns to examine their ability as chiral stationary phases (CSPs) for discrimination of enantiomeric amin o acid, amine and alcohol derivatives. It was found that CSP-(S)-4 prepared from cone-shaped tetra-(S)-1-phenylethylamide (S)-4 showed good to fair se parations for all the samples examined. On the contrary, the corresponding CSP-(S)-14 prepared from the cone-shaped tetraamide (S)-14 of the parent p- tert-butylcalix[4]arene did not indicate any enantioseparation at all for t he same samples, showing that the bridging group of the calix[4]arene ring is critical for the advent of enantioselectivity. The effect of the types a nd the numbers of the chiral amide groups in the chiral selectors on enanti oselectivity was also discussed.