Background
Incorporating positron emitting fluorine-18 into aromatic ring systems plays a very important role in the development of novel biomarkers for use in Positron Emission Tomography (PET). Current methods of preparing biomarkers include nucleophilic fluorine substitution reactions, however the yield obtained by this reaction drops drastically as the complexity of the aromatic ring system increases. UCLA researchers have developed a novel nucleophilic fluorination reaction of aromatic compounds with a no-carrier-added [F-18] fluoride ion. This reaction is suitable for the preparation of F-18 labeled biomarkers containing a variety of substituents and allows for the synthesis of biomarkers and molecular imaging probes for PET with higher yields and purity than currently used methods. The reaction can be expanded to a multitude of labeled and unlabeled molecules.
Description
The basic synthesis method includes a "no-carrier-added" [F-18] fluoride ion reacting with an iodylbenzene derivative, with the fluoride ion nucleophilically substituting the iodyl group (IO2) on the aromatic ring, resulting in regiospecific F-18 labeled aromatic compounds. In the above reaction "a" is either NaOCl or dimethyldioxirane and "b" is a source of no-carrier-added 18F. A large number of iodylbenzene derivative have been reacted using this procedure to produce F-18 labeled aryl analogs. The [F-18] fluoride ion regiospecifically substitutes the iodyl group on the aromatic ring. For example, the PET marker 6-[F-18]-fluoro-L-dopa has been synthesized utilizing this reaction scheme.
Advantages
State Of Development
We continue to demonstrate the broad range of molecules capable of synthesis with this method.