Assembly of ion channel mimics from a modular construction set

Ion channel mimics were assembled from a modular construction set consisting of core units, derived from polycarboxylate 18-crown-6 ethers, wall units, derived from macrocyclic tetraesters, and polar head groups which provide overall amphiphilic character. The preparation of symmetrical and side-discriminated macrocyclic tetraesters from diols and maleic anhydride gave the required macrocycles in low yields by acid-catalyzed esterification, or by carboxylate alkylation. Addition of 1 equiv of 3-mercaptopropanol to the macrocyclic dienes gave the wall unit precursor. Coupling of the walls to the crown ether via esters was achieved by carboxylate alkylation. The syntheses were completed by Michael addition of head group thiolates. Twenty-one candidate ion channels of molecular weight 1600-4800 g/mol were prepared and characterized.