11 C labelling of AG957—a potential tyrphostin radiotracer for PET

Carbon‐11 labelled 4‐( N ‐2,5‐dihydroxybenzyl)amino methyl benzoate (AG957), a potential radiotracer for imaging bcr–abl receptors was synthesized. [ 11 C]AG957 was prepared by labelling 4‐aminobenzoic acid using [ 11 C]CH 3 I, which affords the corresponding [ 11 C] methyl ester in excellent yields. Subsequent condensation of the amino group with 2,5‐dihydroxy‐benzaldehyde formed the respective Schiff base. Reduction of this compound with NaBH 3 CN gave [ 11 C]AG957 in overall decay corrected radiochemical yield of 65–75% (based on 11 CH 3 I) with an average specific radioactivity of 40 GBq/μmol (1.1 Ci/μmol). The total synthesis time from EOB including formulation was 45 min. At physiological pH, the compound was found to be sufficiently stable for in vitro and in vivo investigations. Copyright © 2002 John Wiley & Sons, Ltd.