Fluorine-18 labeling of 6,7-disubstituted anilinoquinazoline derivatives for positron emission tomography (PET) imaging of tyrosine kinase receptors: Synthesis of¹⁸F-Iressa and related molecular probes

Inhibitors of tyrosine kinase enzymatic activity represent a promising new class of antineoplastic agents. Although clinical studies performed over the last decade give more insight on the potential therapeutic applications of such drugs, identification of the individual patients who might benefit from them remains a major challenge. We have developed a synthetic strategy for the production of a wide variety of radiolabeled 6,7-disubstituted 4-anilinoquinazolines suitable for noninvasive imaging of tyrosine kinase receptors to predict therapy effectiveness. Three new F-18 labeled radiopharmaceuticals based on the therapeutic agents Tarceva, Iressa, and ZD6474 were synthesized. Decay-corrected yields varied between 25 and 40% for a total synthesis time of 120 min, thus providing F-18 labeled tyrosine kinase inhibitors in quantities and times practical for use as PET radiopharmaceuticals.