Synthesis of Two Dopamine D4 Receptor Ligands: 11C Labelled Chromeno[3,4-c]pyridin-5-ones

Article abstract of DOI:10.1002/1099-1344(200009)43:10<989::AID-JLCR384>3.0.CO;2-3

The synthesis of two 11C labelled chromeno[3,4-c]pyridin-5-ones for the visualisation of the dopamine D4 receptor subtype has been developed. The production entailed an (9-methylation of the O-desmethyl precursor with [11C]iodomethane in the presence of tetrabutylammonium hydroxide. Subsequent purification by RP-HPLC and formulation by tracer enrichment on a CIS Sep Pak provided a solution which was suitable for human iv injection. Specific activity of the tracer averaged 37 GBq/μmol at EOS and the radiochemical yields were 65 percent (decay-corrected, based on [11C]CH3I). Total activity obtained was 5.6 - 7.4 GBq. The preparations have been demonstrated to be chemically and radiochemically pure by HPLC.