PENTADENTATE CHIRAL AMINE-PHENOL LIGANDS - SYNTHESIS AND RADIOCHEMICAL STUDIES WITH TC-99M

Two pentadentate chiral amine-phenol ligands were synthesized by conde nsing 2-hydroxyacetophenone with diethylenetriamine or 3,3'-diamino-N- methyldipropylamine and reducing the resultant Schiff base ligands wit h NaBH4. The ligands were characterized by H-1 and C-13 NMR spectrosco py. The amine-phenol ligands form a mixture of d, l and meso isomers a nd complexation studies with Tc (99m and/or 99) were done without sepa ration of the isomers. Radiochemical studies of the amine-phenol ligan ds with Tc-99m and Tc-99 were carried out at technetium concentrations varying from 0.1 to 100 mu M. Complex yields were estimated by TLC, p aper electrophoresis and solvent extraction studies. Tc-99m complexes are readily formed in yields > 95% in NCA (TcO4-)-Tc-99m studies, and the resultant complexes were found to be neutral, lipophilic and stabl e. The present studies suggest that the pentadentate chiral ligands ma y be suitable candidates for developing new Tc chelates as radiopharma ceuticals or as bifunctional chelating agents for labeling biomolecule s.