Secondary Amine Derivatives of p-tert-Butylthiacalix[4]arene: Synthesis and Molecular Recognition of Phthalic Acid

New tetrasubstituted p-tert-butylthiacalix[4]arenes containing 2-, 3-, and 4-picolylamine fragments at the lower rim in 1,3-alternate conformation were synthesized. It was shown that the macrocycles synthesized are able to bind selectively phthalic acid in the series of dicarboxylic (oxalic, malonic, succinic, adipic, glutaric, fumaric, maleic, isophthalic and terephthalic) and hydroxy (glycolic and tartaric) acids.