Phenyl Tetraacetic Acid Ligands for Gadolinium: Potential Magnetic-Resonance Image Enhancing Agents

Abstract

Three new ligands suitable for chelation to gadolinium have been synthesized. N,N'- (1,2-Phenylenebis[imino(2-oxoethane-2,l-diyl)])bis[N-(carboxymethyl)glycine] and N,N'-(1,3-phenylenebis[imino(2-oxoethane-2,l-diyl)])bis[N-(carboxymethyl)glycine] were prepared from the corresponding phenylenediamines and N,N'-[1-(4-methylpheny1)ethane-1,2-diyl]bis[N-(carboxymethyl)glycine] from 4-methylbenzaldehyde. Attempted syntheses of other para derivatives of the latter compound produced only oxopiperazinediacetic acids.