Influence of alkali and alkaline earth ions on the O-alkylation of the lower rim phenolic-OH groups of p-tert-butyl-calix[4]arene to result in amide-pendants: template action of K⁺ and the structure of K⁺ bound tetra-amide derivative crystallized with a p-tert-butyl-calix[4]arene anion

Abstract

Role of alkali and alkaline earth ions on the formation of calix[4]arene-amide derivatives through O-alkylation of the lower rim phenolic-OH groups in general and template action of K⁺ in particular have been explored. Na⁺ and K⁺ ions among alkali, and Ca²⁺ and Sr²⁺ ions among alkaline earth have shown tetra-amide derivatives bound to metal ion species. Among all these, potassium salts act as template and yields a K⁺ bound tetra-amide derivative where the charge is counter balanced by a calix[4] arene-monoanion and the product is crystallographically characterized. Change in the amide precursor used in the^se O-alkylation reactions has no effect on the type of the amide derivative formed. Also demonstrated is a direct one-step reaction for the preparation of 1,3-di-amide derivative in high yield and low reaction period using CsHCO₃.