Scheme 1. (A) Synthesis of the theranostic probe TPETP-AA-Rho-cRGD and a schematic representation of the proposed singlet oxygen self-reporting mechanism. Reagents: (a) 1-(3-hydroxyphenyl)-piperazine, TFA; then 2-azidoacetic acid, DMAP, EDC, DMF; (b) propiolic acid, DMAP, DCC, DCM; (c) TEA, THF; (d) cRGD-alkyne, CuSO4, sodium ascorbate, DMSO and water. TFA: trifluoroacetic acid; EDC: N-(3-dimethylaminopropyl)-N′-ethylcarbodiimide hydrochloride; TEA: triethylamine; DMF: dimethylformamide; DCM: dichloromethane; DMAP: 4-(dimethylamino)pyridine; DCC: N,N′-dicyclohexylcarbodiimide; THF: tetrahydrofuran.
