Tricyclic imidazole antagonists of the Neuropeptide S Receptor

A new structural class of potent antagonists of the Neuropeptide S Receptor (NPSR) is reported. NPSR-PI1 demonstrates potent in vitro NPSR antagonism and central exposure in vivo. A new structural class of potent antagonists of the Neuropeptide S Receptor (NPSR) is reported. High-throughput screening identified a tricyclic imidazole antagonist of NPSR, and medicinal chemistry optimization of this structure was undertaken to improve potency against the receptor as well as CNS penetration. Detailed herein are synthetic and medicinal chemistry studies that led to the identification of antagonists 15 and NPSR-PI1, which demonstrate potent in vitro NPSR antagonism and central exposure in vivo.