Synthesis and Pharmacological Evaluation of [11C]4-Methoxy‑N‑[2-(thiophen-2-yl)imidazo[1,2‑a]pyridin-3-yl]benzamide as a Brain Penetrant PET Ligand Selective for the δ‑Subunit-Containing γ‑Aminobutyric Acid Type A Receptors

The α4/6βδ-containing GABAA receptors are involved in a number of brain diseases. Despite the potential of a δ-selective imaging agent, no PET radioligand is currently available for in vivo imaging. Here, we report the characterization of DS2OMe (1) as a candidate radiotracer, 11C-labeling, and subsequent evaluation of [11C]­DS2OMe in a domestic pig as a PET radioligand for visualization of the δ-containing GABAA receptors.