Synthesis, SAR study, and biological evaluation of novel quinoline derivatives as phosphodiesterase 10A inhibitors with reduced CYP3A4 inhibition

[Display omitted] A novel class of phosphodiesterase 10A inhibitors with potent PDE10A inhibitory activity and reduced CYP3A4 inhibition was designed and synthesized starting from 2-[4-({[1-methyl-4-(pyridin-4-yl)-1H-pyrazol-3-yl]oxy}methyl)phenyl]quinoline (1). Replacement of pyridine ring of 1 with N-methyl pyridone ring drastically improved CYP3A4 inhibition, and further optimization of these quinoline analogues identified 1-methyl-5-(1-methyl-3-{[4-(quinolin-2-yl)phenoxy]methyl}-1H-pyrazol-4-yl)pyridin-2(1H)-one (42b), which showed potent PDE10A inhibitory activity and a good CYP3A4 inhibition profile. A PET study with 11C-labeled 42b indicated that 42b exhibited good brain penetration and specifically accumulated in the rodent striatum. Further, oral administration of 42b dose-dependently attenuated phencyclidine-induced hyperlocomotion in mice with an ED50 value of 2.0mg/kg and improved visual-recognition memory impairment at 0.1 and 0.3mg/kg in mice novel object recognition test.