Preparation of macrocyclic and ‘C-clamp’ dicarboxylate compounds

Reductive amination of bis-1,3-(aminomethyl)-4,6-diisopropylbenzene with the 4,4″-dicarboxaldehyde of 1,1′:3′,1″-terphenyl-2′-carboxylic acid, sodium salt, afforded a novel macrocyclic dicarboxylate compound in 71% isolated yield. Purification was effected by filtration in a single step. The synthesis and characterization of two new ‘C-clamp’ compounds, which also contain two m-terphenyl carboxylates but exhibit much greater degree of flexibility, are also described. These compounds are of interest as potential ligands or for host-guest chemistry.