Head-to-tail connected double calix[4]arenes

New macrotricyclic compounds consisting of two calix[4]arene substructures connected by aliphatic chains of various length (three to five carbon atoms) between two oppositep-positions and two distal phenolic oxygens have been synthesized. Starting withp-tert-butyl-calix[4]arene, two O-protected phenolic units are attachedvia ether links in 1,3-position by reaction with the corresponding tosylates. After deprotection, the new calix[4]arene is formed by fragment condensation with 2,6-bisbromomethylated 4-alkylphenols. The structure of one example (8c) has been confirmed by single crystal X-ray analysis. Both calixarene parts assume the cone conformation, a molecule of acetonitrile being inclu…