Synthesis and evaluation of two 18F-labeled imidazo[1,2-a]pyridine analogues as potential agents for imaging β-amyloid in Alzheimer’s disease

Two new fluorinated imidazo[1,2-a]pyridine derivatives, 6-(2′-fluoroethyl)-2-(4′-dimethylamino)phenylimidazo[1,2-a]pyridine (FEPIP) and 6-(3′-fluoropropyl)-2-(4′-dimethylamino)phenylimidazo[1,2-a]pyridine (FPPIP), were synthesized. The binding affinity for FEPIP and FPPIP to amyloid plaques in human AD cortical tissues was determined. Radiolabeling, in vitro film autoradiography, and micro-PET study were performed with [18F]FPPIP to determine its utility as a radioligand for amyloid plaque imaging in the brain of AD patients.