High specific activity tritium-labeled N-(2-methoxybenzyl)-2,5-dimethoxy-4-iodophenethylamine (INBMeO): A high-affinity 5-HT2A receptor-selective agonist radioligand

The title compound ([3H]INBMeO) was prepared by an O,O-dimethylation reaction of a t-BOC protected diphenolic precursor using no carrier added tritiated iodomethane in DMF with K2CO3. Removal of the t-BOC protecting group and purification by HPLC afforded an overall yield of 43%, with a radiochemical purity of 99% and specific activity of 164 Ci/mmol. The new radioligand was suitable for labeling human 5-HT2A receptors in two heterologous cell lines and had about 20-fold higher affinity than [3H]ketanserin.

The title compound 1 was prepared in 99% radiochemical purity at a specific activity of 160 Ci/mmol. It had a Kd of 0.1–0.15 nM in two different heterologous cell lines stably expressing the human serotonin 5-HT2A receptor.Figure optionsDownload as PowerPoint slide