Abstract: Two new DTPA-diamide derivatives bearing two aromatic moieties have been obtained by a modification of DTPA(diethylenetriaminepentaacetic acid) with p^- and o^- aminobenzoic acid. Their gadolinium, ytterbium, and iron complexes have been synthesized and some of them were examined for the role as the contrast agents for magnetic resonance imaging. The results show that the NMR T₁ relaxivitives(R₁) for Gd(Ⅲ) DTPA B4ABA^2- and Gd(Ⅲ) DTPA B2ABA^2- in water solutions are 5.5 and 5.4 L·mmol^-1 ·s^-1, respectively, which are higher than that of their parent complex, GdDTPA^2-.

Key words: Diethylenetriaminepentaacetic acid, Aminobenzoic acid, Modification, Gadolinium chelate, Magnetic resonance imaging contrast agent