A Facile Radiolabeling of [18F]FDPA via Spirocyclic Iodonium Ylides: Preliminary PET Imaging Studies in Preclinical Models of Neuroinflammation

A suitable TSPO PET ligand may visualize and quantify neuroinflammation in a living brain. Herein we report a F-18-ligand, [F-18]2 ([F-18]FDPA), is radiolabeled in high yield and high specific activity based on our spirocyclic iodonium ylide (SCIDY) strategy. [F-18]2. demonstrated saturable specific binding to TSPO, substantially elevated brain uptake, and slow washout of bound PET signal in the preclinical models of brain neuroinflammation (cerebral ischemia and Alzheimer's disease).