Facile synthesis of bis(hydroxamamide)-based tetradentate ligands for 99mTc-radiopharmaceutical

Abstract

A facile, two-step synthesis of the bis(hydroxamamide)-based tetradentate ligands for 99mTc-radiopharmaceuticals is described. Firstly, the hydroxamamide was converted to hydroximic acid chloride by reaction with sodium nitrite in hydrochloric acid at 0 °C. Secondly, treating the halide with the ethylenediamine or 1,3-propylenediamine in absolute ethanol formed the desired products, N, N′-ethylene bis(1-(4-nitroimidazole-1-yl)–propan-hydroxyiminoamide) ( I) and N, N′-propylene bis(1-(4-nitroimidazole-1-yl)-propanhydroxyiminoamide) ( II). The corresponding 99mTc complexes showed high yields and were found by paper electrophoresis to be electrically neutral under physiological conditions. The partition coefficients indicated a distinct difference between the two complexes.