Scheme 4. Synthesis of IN-ABPs.

Synthesis of multiple tagged IN-ABPs labelled with Cy5 based on PAMAM G3 dendrimer core capped with acetyl or PEG groups. PAMAM G3 was first linked to 16 iodine tags by reacting with the IPA-SE (3) then a single GB111NHCO(CH₂)₃CO-SE (9) moiety was attached followed by reacting with Cy5-SE. The remaining free amines were then capped with acetyl, PEG, or left free, generating 21, 22, and 20, respectively. Control compounds lacking the GB111NHCO(CH₂)₃CO-SE (9) moiety were also generated with acetyl, PEG or with free amines, compound 23, 24, and 19 respectively.