N-2-(azol-1(2)-yl)ethyliminodiacetic acids: A novel series of Gd(III) chelators as T-2 relaxation agents for magnetic resonance imaging

The synthesis, physicochemical properties, and toxicological implications o f a novel series of N-2-(azol-1(2)-yl)ethyliminodiacetic acids, useful as c ontrast agents for magnetic resonance imaging are reported. Compounds were prepared by alkylation of methyl iminodiacetate with N-2-bromoethylazoles a nd subsequent hydrolysis. Stability constants of the corresponding Gd(III) complexes and T-1 and T-2 relaxivities were determined and interpreted in t erms of optimized geometries obtained by semiempirical PM3 calculations. Co mpounds show increased T-2 relaxivity and decreased toxicity in vitro as co mpared to EDTA-Gd(III) complexes. (C) 1999 Elsevier Science Ltd. All rights reserved.