Synthesis of Polyester Dendritic Scaffolds for Biomedical Applications

Using a well‐defined poly(2,2‐bis(hydroxymethyl)propanoic acid) dendrimer scaffold, a series of G1 to G3 dendrons is functionalized at the periphery with alkynes to enable “Click” functionalization via the copper‐catalyzed alkyne–azide cycloaddition (CuAAC). The resulting dendrons are further functionalized at the core with a dipicolylamine (DPA) moiety to enable radiolabeling with ^99mTc for molecular imaging applications. Efficient CuAAC coupling is achieved using an azide‐functionalized triethylene glycol monomethyl ether (TEG‐N₃). Removal of copper from the DPA ligand is successfully performed on G1 and G2 dendrimers prior to radiolabeling with ^99mTc. Radiolabeling of the G3 dendrimer is accomplished via transmetallation of the [CuDPA]²⁺ ligand with ^99mTc, further demonstrating the feasibility of the synthetic strategies in the preparation of dendritic imaging agents. Subsequent attachment of an acyloxymethyl ketone (AOMK) derivative for targeting of cathepsin B is also explored. Despite demonstrating the ability to ligate multiple AOMK ligands, the AOMK–dendrimer conjugates are not able to bind to cathepsin B, which may be attributed to steric hindrance at the dendrimer periphery. image