Synthesis of F-labelled aryl trifluoromethyl ketones with improved molar activity.

A method for the radiosynthesis of F-labelled aryl trifluoromethyl ketones starting from widely available Weinreb amides using [F]fluoroform is presented. The method uses potassium hexamethyldisilazane as base and delivers products in high molar activity (up to 24 GBq μmol) and excellent radiochemical conversions. The applicability for PET tracer synthesis is demonstrated by the radiosynthesis of ten (hetero)aryl trifluoromethylketones, bearing electron-withdrawing and -donating substituents including a derivative of bioactive probenecid.