Synthesis and characterization of tritium labeled 2,3,4,9-tetrahydro-lH-carbazoles as potent DP receptor antagonists

摘要

Tritium labeled 2,3,4,9-tetrahydro-lH-carbazole la and 2a were prepared in good yields with a specific activity of 7.0Ci/mmol (214GBq/mmol) and 4.2Ci/mmol (155GBq/mmol), respectively. Both compounds have been synthesized in high radiochemical purity by catalytic tritium-bromine exchange of the corresponding aryl bromide precursors. The 6-bromocarbazole precursors 7 and 8 were prepared as a mixture by a three step process, involving regioselective bromination of 3c with pyridinium tribromide, oxidation of thioether 4c using m-CPBA and hydrolysis of acylsultamcarbazole 5c. Finally, HPLC separation of the enantiomers afforded the 6-bromo precursors 7 and 8 in high diastereomeric ratio (dr 99% and dr 93% respectively).