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. DOTA heroes: DOTAZA is a tunable analogue of the well‐known chelator DOTA. Both enantiomers of DOTAZA and related derivatives were synthesized by click functionalization and metal chelates with Na, Cu, and Gd were characterized by X‐ray analysis.