Synthesis of tetradentate mixed bisphosphonates—new hydroxypyridinonate ligands for metal chelation therapy

In a general study for developing better drugs suitable for Fe, Al, Co or lanthanide chelation therapy experiments, new mixed bisphosphonate-hydroxy pyridonates were synthesized. We demonstrate that the method using amidation reaction and dealkylation by concentrated hydrochloric acid gives excellent results for amino bisphosphonic acid ligands having at least two carbons between the amino group and the methylene bisphosphonic acid group.