The synthesis of macrocyclic polyether‐diester ligands containing a long‐chain alkoxy substituted pyridine subcyclic unit

Two new series of macrocyclic polyether‐diester ligands have been prepared containing 4‐pentoxy‐ and 4‐octoxypyridine subcyclic units. The 4‐alkoxy‐2, 6‐pyridinedicarboxylic acid derivatives used as starting materials were prepared from 4‐chloro‐2, 6‐pyridinecarbonyl chloride. The 4‐octoxydiketopyridino‐18‐crown‐6 ligand greatly facilitates the transport of silver ions across a chloroform liquid membrane.