Synthesis, characterization and biodistribution in mice of oxotechnetium(V) (SNS/S) mixed ligand complexes with N,N-bis(2-mercaptoethyl)(2-piperidin-1-ylethyl)amine as tridentate ligand.

A new SNS tridentate ligand containing piperidine group as pendant amine, N ,N-bis(2-mercaproethyl)(2-piperidin-1-ylethyl)amine, was synthesized by alk ylation of bis(2-benzylthioethyl)amine with 1-(2-chloroethyl)piperidine in the presence of NaI, and deprotection of the thiols using Na/NH3. Three neu tral oxotechnetium mixed ligand complexes [SNS/S] with either p-toluenethio l, benzylmercaptan, or p-methoxybenzylmercaptan, were synthesized at carrie r level [Tc-99] and characterized by elemental analysis, UV-vis, IR and H-1 NMR spectroscopies. The complex with p-toluenethiol as coligand was also c haracterized by x-ray crystallography. The same complexes were also prepare d at tracer level [Tc-99m], and their in vivo biodistribution was investiga ted in mice. All Tc-99m complexes have fast blood clearance, high uptake an d significant retention into the brain.