Synthesis of Chelating Agents. VI. Chelating Behavior of 1,2,3-Triaminopropanehexaacetic Acid with Divalent Metal Ions

A Concise and Safe Synthesis of 1,2,3‐Propanetriamine (PTA)

“…The vicinal positioning of all three nitrogen atoms and their symmetric arrangement play a key role in the formation of stable metal complexes of native PTA with different chelation configurations. [7] Additional exploitation of the valuable coordinating properties of PTA comes from the preparation of substituted derivatives with higher denticity, such as tripodal chelating agents, [8] the polyaminocarboxylic 1,2,3-propanetriamine-N,N,N',N',N",N"-hexaacetic acid, [9] or its incorporation in conformationally constrained derivatives such as the efficient 6-amino-1,4-diazepane ("AAZTA") based chelators. [10] In its nearly 150 years history, different synthetic approaches have been developed for the preparation of PTA, briefly summarised in Scheme 2, none of them suitable for a largescale preparation.…”