Scheme 1

Synthesis of IR783-AMBF₃. (a) 1.2 eq. 4-Carboxyphenylboronic acid, 0.1 eq. Pd(PPh₃)₄, H₂O/DMF (10:1), 10 h, 100 °C. (b) 1.2 eq. N,N-dimethylethyl amine, 1.5 eq. HOBt, 1.5 eq. Py, 3.0 eq. EDC. HCl, DMF, 5 h, RT. (c) (i) 2.0 eq. Bromomethylboronic acid pinacol ester, 1.0 eq. N,N-diisopropylethylamine, DMF, 3 h, RT. (ii) 2.0 M KHF₂, 1.0 M HCl, 0.5 h, RT. (d) Radiolabeling 1 M Pyridazine-HCl, 40 mCi aqueous [¹⁸F]-fluoride ion (Specific concentration of > 1.5 Ci/mL), 80 °C, 25 min. Bottom middle structure: IR783-AMBF₃, a derivative of IR783; Bottom right structure: Fc-AMBF₃, a previously published fluorescein derivative, to be compared with IR783-AMBF₃