Identification of fused bicyclic heterocycles as potent and selective 5-HT2A receptor antagonists for the treatment of insomnia

A series of fused bicyclic heterocycles was identified as potent and selective 5-HT2A receptor antagonists. Optimization of the series resulted in compounds that had improved PK properties, favorable CNS partitioning, good pharmacokinetic properties, and significant improvements on deep sleep (delta power) and sleep consolidation.