Tritium labelled (+-)-7-chloro-8-hydroxyl-3-methyl-1-phenyl-2,3,4,5-tetrahydro-1H-3-benzazepine (SCH23390)

The antipsychotic drug, SCH23390, once thought to be the first selective D1 dopamine antagonist, is now believed to possibly produce its profound antidopaminergic and antipsychotic effects via molecular sites that involve recognition characteristics similar to, or are a subpopulation of the D1 dopamine receptors. Tritium labelled SCH23390 has been prepared by palladium catalyzed reductive aryl debromination of a brominated precursor with carrier free tritium gas in THF. The product is labelled in the 9-position of the benzazepine ring and a specific activity of 5.6 Ci/mmole was obtained. (author)