Lead Optimization of Thiazolo[5,4‐c]piperidines: 3‐Cyclobutoxy Linker as a Key Spacer for H3R Inverse Agonists

The simpler, the better: H(3) histamine receptor (H(3)R) are of interest as therapeutic targets in cognitive and somnolence disorders. Here, lead optimization of H(3)R inverse agonists bearing a thiazolo[5,4-c]piperidine group gave rise to a clinical candidate with a much simpler unprecedented benzamide scaffold, displaying decreased hERG activity while maintaining high brain receptor occupancies.