Discovery of 2-((2-chloro-6-fluorophenyl)amino)-N-(3-fluoro-5-(trifluoromethyl)phenyl)-1-methyl-7,8-dihydro-1H-[1,4]dioxino[2',3':3,4]benzo[1,2-d]imidazole-5-carboxamide as potent, selective and efficacious microsomal prostaglandin E2 synthase-1 (mPGES-1) inhibitor

The discovery and SAR of potent, selective dioxane-fused tricyclic benz[d]imidazole derivatives as mPGES-1 inhibitor are herein described. Various amide modifications in this series afforded many potent mPGES-1 inhibitors, of which 17d proved to be suitable for further profiling in vivo. Compound 17d {2-((2-chloro-6-fluorophenyl)amino)-N-(3-fluoro-5-(trifluoromethyl)phenyl)-1-methyl-7,8-dihydro-1H-[1,4]dioxino[2',3':3,4]benzo[1,2-d]imidazole-5-carboxamide} exhibited excellent mPGES-1 enzyme (IC₅₀: 8nM), cell (A549 IC₅₀: 16.24nM) and human whole blood potency (IC₅₀: 249.9nM). In rodent species, 17d strongly inhibited guinea pig mPGES-1 (IC₅₀: 10.79nM), but not the rat and mouse enzyme. Furthermore 17d displayed excellent in vitro selectivity over mPGES-2, cPGES, COX-enzymes (COX-1, 2), selectivity against Other prostanoid synthases, favorable hERG and CEREP panel profile. Likewise, our lead 17d demonstrated good oral pharmacokinetic profiles and good CNS B/P ratio in rat and guinea pig. Lead 17d also unveiled good efficacy in LPS-induced thermal hyperalgesia pain model with ED₅₀ of 36.7mg/kg, respectively.