Synthesis, 11C labeling and biological properties of derivatives of the tyrphostin AG957

Four analogues of AG957, a known inhibitor of the tyrosine kinase p210bcr-abl, have been synthesized and tested for their growth inhibitory effect against the BCR/ABL-positive FDrv210C cells as well as the epidermal growth factor (EGF) receptor-positive Baf/ERX cells. All compounds that can undergo oxidation to the corresponding quinone demonstrated inhibition of FDrv210C cells and Baf/ERX cells. Compounds that cannot become oxidized showed significantly less inhibition of BCR/ABL- or EGF receptor-mediated cell proliferation. The 11C-labeled compounds were prepared by labeling 4-aminobenzoic acid using [11C]CH3I, which afforded the corresponding 11C-labeled methyl ester in excellent yields. Subsequent condensation of the amino group with an appropriately substituted hydroxy benzaldehyde formed the respective Schiff base. Reduction of this compound with NaBH3CN gave the 11C-labeled inhibitors in an overall radiochemical yield of 17.3±2.1% (n=3; not decay corrected) and an average specific radioactivity of 40 GBq/µmol (1.1 Ci/µmol) at the end of synthesis. The total synthesis time from EOB including HPLC purification and formulation was 45 min.