2- and 4-[18F]Fluorophenols from Baeyer-Villiger Oxidation of [18F]Fluorophenylketones and [18F]Fluorobenzaldehydes

2- or 4-[18F]Fluorophenols were isolated with 28–40% radiochemical yield (decay corrected, purity >98%, 35 min synthesis time) from [18Flfluoroacetophenone and/or [18F]fluorobenzophenone by a Baeyer-Villiger oxidation using m-chloroperbenzoic acid in the presence of trifluoroacetic acid at 120–130°C for 15 min. This reagent was also able to transform [18F]fluorobenzaldehydes into the corresponding phenols in 23–25% radiochemical yield (decay corrected, 45 min synthesis time). In order to optimize the synthesis of [18F]fluorophenols, the [18F]fluorination of nitrosubstituted benzaldehyde, acetophenone and benzophenone was studied and the results compared with those previously published. Under similar conditions 4-nitroacezophenone was shown to be the most reactive substrate compared to nitrobenzaldehyde or nitroacetophenone.