Template-directed synthesis of macrocyclic aminopyridines: azacalix[n](2,6)pyridines (n = 3, 4)

Template-induced synthetic routes for azacalix[n](2,6)pyridines (n = 3, 4) have been elaborated. The proton and nickel ion served as the efficient template for the cyclization reactions, and the presence of the templates preferentially afforded the cyclic trimers and tetramers in moderate to good yields, respectively. The compatibility of the cyclic tetramer with nickel ion was also confirmed by X-ray crystallography.