Carbon-14 labeling of a trifluoromethoxy group: synthesis of a substance P antagonist

Synthesis of a carbon-14 labeled trifluoromethoxy group has been accomplished using the stepwise oxidative fluorination-desulfurization of a readily prepared [C-14]xanthate (5). This novel labeling procedure allowed a rapid synthesis of substance P antagonist candidate 1 that avoided potentially more complex ring-labeling procedures. Similar procedures have been used to prepare C-14 labeled trifluoromethyl and trifluoromethylamine groups. Copyright (C) 2001 John Wiley & Sons, Ltd.