Metal-Mediated C-H Radiofluorination for Rapid Access to PET Imaging Agents

Project Summary/Abstract Fluorine is an essential constituent of many commercial molecules, including (radio)pharmaceuticals, agrochemicals, and functional materials. Fluorine-19 (stable isotope) is routinely introduced into aromatic pharmaceuticals in order to modulate pharmacological properties. Many positron emission tomography aromatic

(PET) imaging agents are labeled with fluorine-18 (radioactive isotope) for studying and monitoring disease, as well as evaluating drug-target engagements and enriching clinical trials. Considerable progress has been made in the development of aromatic fluorine-18 imaging agents for these applications, although more robust

radiosyntheses are required to support and expedite tracer discovery and meet the increasing demand for radiopharmaceuticals from the healthcare and pharmaceutical industries. The primary aim of this project is to overcome challenges associated with radiofluorination through the invention of radiosynthetic methods that

support the design of aromatic PET imaging agents. Specifically, the central claim is that radiofluorinated organic molecules can be accessed by designing silver- and copper-containing species competent in C-H radiofluorination. Copper is an abundant and inexpensive element that has previously been shown to

(radio)fluorinate aromatic C-H bonds, albeit with a limited scope. Silver resides in the same periodic group as copper and preliminary data suggests that it can induce C-H radiofluorination transformations. To achieve these goals, the proposal is divided into three aims: Aim 1 is to use fluorine-18 labeled silver compounds for the

radiofluorination of organic molecules. Aim 2 is to utilize this method for the automated radiosynthesis of fluorine- 18 labeled bioactive molecules Aim 3 is to develop new copper-mediated C-H functionalization methodologies for the direct, automated fluorine-18 labeling of aromatic bioactive molecules. Ultimately, enhancement of this

imaging modality as described in this grant is expected to fundamentally alter the current radiosynthetic paradigm and expedite aromatic radiofluorination, providing new and rapid access to fluorine-18 labeled pharmaceuticals used in PET. Importantly, developments in PET biotechnology are continually being used to fundamentally

improve the detection, treatment, and prevention of disease, consistent with the mission of NIBIB. This grant builds on the ongoing multidisciplinary collaboration between Prof Peter J. H. Scott (Department of Radiology) and Prof Melanie S. Sanford (Department of Chemistry), which focuses on the development of radiosynthetic

methods at the University of Michigan. The facilities and faulty/staff expertise offered in these laboratories provide an outstanding research environment that will facilitate the candidate's acquisition of further skills necessary for gaining an academic position at a US institution, consistent with his long-term career goal. In

particular, this project will provide new opportunities to merge radiochemistry and organometallic chemistry, which will serve the candidate's career development toward a professorship in chemistry with a focus on C-H radiolabeling for PET applications.