High yield synthesis ofN202 type unsymmetrical Schiff base ligands with one iminic moiety: An unusual reactivity towards 2-hydroxy-5-bromobenzaldehyde

Novel N202 type unsymmetrical Schiff base ligands containing one iminic moiety were synthesized viadeliberate choose of the precursors. The method applied to their synthesis gave the target ligands in highoverall yieldʹ) (70-80%). In this method nitro-substituted aniline was condensed with an aldehyde and hoth ofthe resulting imine and nitro groups were reduced to amine with ammoniumformate and palladium oncharcoal as catalyst to give the desired half-unit. The resulting half-unit was condensed with anotheraldehyde to give the target ligands. An unusual reactivity wa~ observed in the case ofthe reaction ofthe halfunitwith 5-hromosa/icylaldehyde, which resulted in the synthesis ofsymmetrical diimino Schiffbase ligand