Paramagnetic metal chelate complexes of DTPA modified by aminobenzoic acid and their NMR T1 relaxivitives

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-B4ABA2- and Gd(III) DTPA-B2ABA2- in water solutions are 5.5 and 5.4 L·mmol-1·s-1, respectively, which are higher than that of their parent complex, GdDTPA2-.