Synthesis procedure for routine production of [carbonyl-11C]desmethyl-WAY-100635

An improved one-pot synthesis procedure for routine production of [carbonyl-11C]desmethyl-WAY-100635 ([11C]DWAY) is described. An efficient purification of the crude product has also been developed and was accomplished by C-18 reversed-phase semi-preparative HPLC using 55/45 EtOH–NaH2PO4 buffer (20 mM, pH=6.5) as the eluent. The desired product fraction was collected in a 2.0–2.5 mL volume and formulated with 11 mL of 0.9% saline. The radioligand was ready for human use in 45 min (EOB). The product was obtained with a radiochemical yield of 11.1±1.8% (EOB, n=15) with a radiochemical purity of >99%. Specific activity was 133.2–185.0 GBq/μmol (3.6–5.0 Ci/μmol, EOS, n=2) when ca. 37.0 GBq (ca. 1.0 Ci) of starting [11C]CO2 was used. Unlabeled mass of [11C]DWAY was found to be 0.15–0.24 μg/mL and the precursor was present in less than 50 ng/mL in final production solution.