Synthesis of Trismacrocyclic and Macrotricyclic Compounds Possessing Structural Fragments of Aza- and Diazacrown Ethers, Cyclen and Cyclam via Pd-Catalyzed Amination Reactions

Abstract

Synthesis of trismacrocyclic compounds with a central tetraazamacrocyclic moiety and two aza-crown ether fragments was carried out using the Pd-catalyzed amination of trans-bis(bromobenzyl) substituted cyclen and cyclam with 3 equiv. of azacrown ethers. The yields were shown to be dependent on the nature of the starting tetraazamacrocycles and reached 45 % in the best case. Formation of the cylindrically-shaped cryptands was achieved by reacting equimolar amounts of trans-bis(bromobenzyl) substituted cyclen or cyclam and diazacrown ethers. The yields of the target cryptands reached 30 % and a clear dependence of the result of the reaction on the reciprocal position of two bromine atoms and two nitrogen atoms in the reactants was observed.