A synthetic scheme is elaborated to prepare two polyaza-macrocycles in which one nitrogen atom is distinct from the others. Thus,(tri-N-methyl)-1, 4, 7, 10-tetraazacyclododecane and (tetra-N-methyl)-1, 4, 7, 10, 13-pentaazacyclopentadecane were synthesised. Through acylation and alkylation reactions, the remaining secondary nitrogen site allows further modifications of the ligand structures and leads to new cyclic polyamines bearing lateral ...