A simple and efficient synthetic protocol is developed for the preparation of heterodentate azomethine ligands bearing various functionalities, by Schiff condensation of dialdehydes with monoprotected diamine followed by reduction of the azomethine bond and deprotection. The efficient procedure of obtaining N-tert-butoxycarbonyl-protected o-phenylenediamine in large scale is also elaborated.
Schiff bases - aromatic diamines - cyclizations - macrocycles - regioselectivity - heteropolydentate ligand