Synthesis of 1,4,7,10-tetra-azacyclododecan-1,4,7,10-tetra-azidoethylacetic acid (DOTAZA) and related "clickable" DOTA derivatives.

Herein, we report the synthesis of two enantiomeric DOTAZA esters and a related DOT3AZA ester. These compounds are tunable analogues of the well-known chelator DOTA and can be easily functionalized through click chemistry of the side-chain azide groups. Like DOTA, DOTAZA forms complexes with various di- and trivalent metals, as demonstrated in the synthesis and structural analysis of CuDOTAZA and the preparation of GdDOTAZA.