Synthesis, characterization and biodistribution of new 99mTc oxo and nitrido complexes with bi- and tetradendate unsaturated NS and N2S2 Schiff bases derived from 2-aminocyclopentene-1-dithiocarboxylic acid as potential heart imaging agents.

The synthesis, characterization and 99mTc labelling of unsaturated diamino dithiol ligands with methyl dithiocarboxylate functions: 2-aminocyclopentene-1-dithiocarboxylic methyl ester (H2L1), N,N'-ethylene bis(methyl 2-aminocyclopentene-1-dithiocarboxylate) (H2L2) and N,N'-propylene bis (methyl 2-aminocyclopentene-1-dithiocarboxylate) (H2L3) are described. Cationic oxo (Tc = O) and neutral nitrido (Tc = N) complexes were obtained. Biodistribution studies in rat showed a good heart uptake of 99mTcN-L2 (2% ID at 5 min) with a high heart-to-blood ratio (5.8 at 5 min), but this complex also exhibited high lung and liver uptake.