Synthesis of a sialyl LewisX mimetic conjugated with DTPA, potential ligand of new contrast agents for medical imaging

The structure of a mimetic of sialyl Lewis(X), namely 3-[2-(alpha-D-mannopyranosyloxy)phenyl]phenylacetic acid, was coupled to diethylenetriaminepentaacetic acid (DTPA) via a flexible alkyl spacer and the amide linkage. The overall yield of the eleven-step synthesis starting from 3-bromophenylacetic acid was 4-8%. This new ligand is expected to target inflammation sites through specific interactions with selectins, the adhesion molecules expressed on the vascular endothelium in pathological conditions. In particular, complexation of the DTPA moiety with gadolinium or radionuclides could produce contrast agents for medical imaging. ((C) Wiley-VCH Verlag GmbH, 69451 Weinheim, Germany, 2002).