Novel lactide derivatives of p-tert-butylthiacalix[4]arene: Directed synthesis and molecular recognition of catecholamines

Abstract

Three stereoisomeric forms of p-tert-butylthiacalix[4]arene (cone, partial cone, and 1,3-alternate conformations) have been proposed as macrocyclic scaffold to obtain dendrimer-like compounds. Modification of the macrocycle with fragments containing both amide and lactide groups made it possible to obtain original analogs of dendrimers with symmetric and asymmetric structures. These compounds are capable of binding catecholamines (dopamine, epinephrine, and norepinephrine). The influence of the macrocyclic platform conformation of the compounds obtained on the efficiency and selectivity of their complexation with catecholamines was established by UV–visible, fluorescence and NMR spectroscopy. It was found that the 1,3-alternate conformation of the macrocycle core was the most favorable for binding all the guests. In case of the cone conformation, selectivity of binding of epinephrine and norepinephrine was observed. Location of catecholamines in the resulting complexes against the macrocyclic platform affected the efficiency of interaction of the synthesized thiacalixarenes with guests.