Synthesis and preliminary evaluation of [C-11]KF17837, a selective adenosine A(2A) antagonist

An C-11-labeled selective adenosine A(2A) antagonist, (E)-8-(3,4-dimethoxystyryl)-1,3-dipropyl-7-[C-11]-methylxanthine ([C-11]KF17837), was prepared by reaction of (E)-8-(3,4-dimethoxystyryl)-1,3-dipropylxanthine thine and ([C-11]methyl iodide with decay-corrected radiochemical yield of 19-50%, radiochemical purity of >99%, sp. act. of 17-100 GBq/mu mol and preparation time of 20-25 min. In mice, the myocardium showed the highest (13.4% ID/g) at 5 min after i.v. injection, which decreased gradually with time. The specific myocardial uptake was visualized by gamma-camera. In the brain region the radioactivity level was higher in the A(2A) receptors-rich striatum than in the cortex and cerebellum. The specific striatal uptake in rats was clearly demonstrated by PET. These results have shown that [C-11]KF17837 is a potential PET radioligand for mapping the adenosine A(2A) receptors in the heart and brain.