Synthèse et études structurales de nouveaux complexes polyhydroxamiques du fer(III) potentiellement utilisables en imagerie par résonance magnétique nucléaire.Deuxième partie: Études des complexes formés in situ à partir d'acides hydroxamiques. Relaxivité du complexe Fe(III) - N,N′-bis(acétylhydroxyamino-3′ propyl)-(amino-4″ butyloxy)-4 pyridine-2,6 dicarboxamide

Numerous analogous dihydroxamates of rhodotorulic acid have been prepared, and their mode of complexation of iron(III) and the stability of these complexes studied as a function of pH, for comparison with ferrioxamine B and the complex of acetohydroxamic acid with iron(III). This study has shown that the stoichiometry of the complexes is 2:3 (at a pH of 7) and 1:1 (at a pH of 2), and that, in spite of a complete complexation, their electrochemical behaviour varies greatly with pH. The very strong complexation constant observed (log β 110 = 21.3) at a pH of 1 with the ligand N,N′-bis(acetylhydroxamino-3′ propyl)-pentyloxy-4 pyridine-2,6-dicarboxamide confirms the strong complexation capacity of iron(III) by these complexes. The high relaxivity of the complex of iron(III) with the N,N′-bis(acetylhydroxyamino-3′ -propyl)-(amino-4″ -butyloxy)-4-pyridine-2,6-dicarboxamide suggests that this product could be a useful contrasting agent for nuclear magnetic imaging. [Journal translation]