Synthetic Route to Novel Asymmetric Tetradentate Ligands Containing Both Amino and Imino Groups

The synthesis of a new asymmetric ligand (E)-4-bromo-2-(((2-((5-bromo-2-hydroxybenzyl)(methyl)amino)ethyl)imino)methyl)phenol, which was conceived to model the asymmetry in the active site of peroxidase/catalase mimics, is reported. The new synthetic route involves seven steps: 1) obtention of phthalimido-acetal; 2) Acetal deprotection; 3) Synthesis of the salicylamine; 4) Obtention of the benzoxacine; 5) Reduction of the benzoxacine with NaBH3CN; 6) Reduction with hydrazine to form salycilamine; 7) Synthesis of the final ligand by condensation of salicylamine with salycilaldehyde. All organic products were characterised by microanalysis and 1H NMR, IR and mass spectroscopies.