Synthesis of N-succinimidyl-5-(tributylstannyl)-3-pyridinecarboxylate(SPC) and its iodination

In order to alleviate the in vivo deiodination of radioiodine-labeled biomolecules, a novel precursor, N-succinimidyl-5-(tributylstannyl)-3-pyridinecarboxylate(SPC), is synthesized in an oxygen- and water-free argon atmosphere. After the optimization of the synthetic experimental conditions, the SPC yield reaches 45%. The product is characterized by 1H NMR and MS. N-succinimidyl-5-iodo-3-pyridinecarboxylate(SIPC) is also synthesized as a standard reference material. 125I labeled SPC is prepared with a labeling rate better than 80% and radiochemical purity higher than 97% after HPLC purification. The radiochemical purity remains over 92% after 24 h storage at 4°C.