4-phenoxypiperidine pyridazin-3-one histamine H(3) receptor inverse agonists demonstrating potent and robust wake promoting activity.

Structure-activity relationships for a series of phenoxypiperidine pyridazin-3-one H(3)R antagonists/inverse agonists are disclosed. The search for compounds with improved hERG and DAT selectivity without the formation of in vivo active metabolites identified 6-[4-(1-cyclobutyl-piperidin-4-yloxy)-phenyl]-4,4-dimethyl-4,5-dihydro-2H-pyridazin-3-one 17b. Compound 17b met discovery flow criteria, demonstrated potent H(3)R functional antagonism in vivo in the rat dipsogenia model and potent wake activity in the rat EEG/EMG model at doses as low as 0.1 mg/kg ip.