6-Benzhydryl-4-amino-quinolin-2-ones as Potent Cannabinoid Type 1 (CB1) Receptor Inverse Agonists and Chemical Modifications for Peripheral Selectivity.

A novel series of 6-benzhydryl-4-amino-quinolin-2-ones was discovered as cannabinoid type 1 receptor (CB1R) inverse agonists based on the high-throughput screening hit, compound 1a. Structure-activity relationships were studied to improve in vitro/in vivo pharmacology and restrict distribution to the peripheral circulation. We adopted several strategies such as increasing topological polar surface area, incorporating discrete polyethylene glycol side chains, and targeting P-glycoprotein (P-gp) to minimize access to the brain. Compound 6a is a P-gp substrate and a potent and highly selective CB1R inverse agonist, demonstrating excellent in vivo metabolic stability and a low brain to plasma ratio. However, brain receptor occupancy studies showed that compound 6a may accumulate in brain with repeat dosing. This was evidenced by compound 6a inhibiting food intake and inducing weight loss in diet-induced obese mice. Thus, a strategy based on P-gp efflux may not be adequate for peripheral restriction of the disclosed quinolinone series.

Discovery of Orally Efficacious Tetrahydrobenzimidazoles as TGR5 Agonists for Type 2 Diabetes.

We have discovered a novel series of tetrahydrobenzimidazoles 3 as TGR5 agonists. Initial structure-activity relationship studies with an assay that measured cAMP levels in murine enteroendocrine cells (STC-1 cells) led to the discovery of potent agonists with submicromolar EC50 values for mTGR5. Subsequent optimization through methylation of the 7-position of the core tetrahydrobenzimidazole ring resulted in the identification of potent agonists for both mTGR5 and hTGR5 (human enteroendocrine NCI-H716 cells). While the lead compounds displayed low to moderate exposure after oral dosing, they significantly reduced blood glucose levels in C57 BL/6 mice at 30 mg/kg and induced a 13-22% reduction in the area under the blood glucose curve (AUC)0-120 min in oral glucose tolerance tests (OGTT).

Evaluation of anti-diabetic effect and gall bladder function with 2-thio-5-thiomethyl substituted imidazoles as TGR5 receptor agonists.

A novel series of 2-thio-5-thiomethyl substituted imidazoles was discovered to be potent TGR5 agonists that possessed glucose-lowering effects while inhibiting gall bladder emptying in mice.

Tetrahydroindazole derivatives as potent and peripherally selective cannabinoid-1 (CB1) receptor inverse agonists.

A series of potent and receptor-selective cannabinoid-1 (CB1) receptor inverse agonists has been discovered. Peripheral selectivity of the compounds was assessed by a mouse tissue distribution study, in which the concentrations of a test compound in both plasma and brain were measured. A number of peripherally selective compounds have been identified through this process. Compound 2p was further evaluated in a 3-week efficacy study in the diet-induced obesity (DIO) mouse model. Beneficial effects on plasma glucose were observed from the compound-treated mice.

Tetrahydropyrazolo[4,3-c]pyridine derivatives as potent and peripherally selective cannabinoid-1 (CB1) receptor inverse agonists.

Peripherally restricted CB1 receptor inverse agonists hold potential as useful therapeutics to treat obesity and related metabolic diseases without causing undesired CNS-mediated adverse effects. We identified a series of tetrahydropyrazolo[4,3-c]pyridine derivatives as potent and highly peripherally selective CB1 receptor inverse agonists. This discovery was achieved by introducing polar functional groups into the molecule, which increase the topological polar surface area and reduce its brain-penetrating ability.

The discovery and SAR of cyclopenta[b]furans as inhibitors of CCR2.

The discovery of a novel series of cyclopenta[b]furans as CCR2 inhibitors is discussed. This series has excellent CCR2 potency and PK characteristics, and good cardiovascular safety.

Discovery and SAR of 5-aminooctahydrocyclopentapyrrole-3a-carboxamides as potent CCR2 antagonists.

SAR study of 5-aminooctahydrocyclopentapyrrole-3a-carboxamide scaffold led to identification of several CCR2 antagonists with potent activity in both binding and functional assays. Their cardiovascular safety and pharmacokinetic properties were also evaluated.

A novel series of N-(azetidin-3-yl)-2-(heteroarylamino)acetamide CCR2 antagonists.

The inflammatory response associated with the activation of C-C chemokine receptor CCR2 via it's interaction with the monocyte chemoattractant protein-1 (MCP-1, CCL2) has been implicated in many disease states, including rheumatoid arthritis, multiple sclerosis, atherosclerosis, asthma and neuropathic pain. Small molecule antagonists of CCR2 have been efficacious in animal models of inflammatory disease, and have been advanced into clinical development. The necessity to attenuate hERG binding appears to be a common theme for many of the CCR2 antagonist scaffolds appearing in the literature, presumably due the basic hydrophobic motif present in all of these molecules. Following the discovery of a novel cyclohexyl azetidinylamide CCR2 antagonist scaffold, replacement of the amide bond with heterocyclic rings was explored as a strategy for reducing hERG binding and improving pharmacokinetic properties.

Novel 2-aminooctahydrocyclopentalene-3a-carboxamides as potent CCR2 antagonists.

Novel CCR2 antagonists with a novel 2-aminooctahydrocyclopentalene-3a-carboxamide scaffold were designed. SAR studies led to a series of potent compounds. For example, compound 51 had a good PK profile in both dog and monkey, and exhibited excellent efficacy when dosed orally in an inflammation model in hCCR2 KI mice. In addition, an asymmetric synthesis to the core structures was developed.

Discovery of a 4-Azetidinyl-1-thiazoyl-cyclohexane CCR2 Antagonist as a Development Candidate.

We have discovered a novel series of 4-azetidinyl-1-aryl-cyclohexanes as CCR2 antagonists. Divergent SAR studies on hCCR2 and hERG activities led to the discovery of compound 8d, which displayed good hCCR2 binding affinity (IC50, 37 nM) and potent functional antagonism (chemotaxis IC50, 30 nM). It presented an IC50 of >50 µM in inhibition of the hERG channel and had no effect on the QTc interval up to 10 mg/kg (i.v.) in anesthetized guinea pig and dog CV studies. It also displayed high selectivity over other chemokine receptors and GPCRs, and amendable oral bioavailability in dogs and primates. In a thioglycollate-induced inflammation model in hCCR2KI mice, it had ED50 of 3 mg/kg on inhibition of the influx of leukocytes, monocytes/macrophages, and T-lymphocytes.

The discovery of novel cyclohexylamide CCR2 antagonists.

As a result of further SAR studies on a piperidinyl piperidine scaffold, we report the discovery of compound 44, a potent, orally bioavailable CCR2 antagonist. While having some in vitro hERG activity, this molecule was clean in an in vivo model of QT prolongation. In addition, it showed excellent efficacy when dosed orally in a transgenic murine model of acute inflammation.

Design, synthesis and SAR of indazole and benzoisoxazole containing 4-azetidinyl-1-aryl-cyclohexanes as CCR2 antagonists.

A novel series of 4-azetidinyl-1-aryl-cyclohexanes containing indazole or benzoisoxazole moiety have been identified as potent CCR2 antagonists with high selectivity versus hERG.

Overcoming hERG activity in the discovery of a series of 4-azetidinyl-1-aryl-cyclohexanes as CCR2 antagonists.

A series of 4-azetidinyl-1-aryl-cyclohexanes as potent CCR2 antagonists with high selectivity over activity for the hERG potassium channel is discovered through divergent SARs of CCR2 and hERG.

Synthesis and structure-activity relationship of 7-azaindole piperidine derivatives as CCR2 antagonists.

The synthesis and structure-activity relationship of a series of 7-azaindole piperidine derivatives are described. SAR studies led to the discovery of the potent CCR2 antagonists displaying IC(50) values in the nanomolar range. The representative compound 15 showed reasonable P450 and pharmacokinetics profile.

Substituted dipiperidine alcohols as potent CCR2 antagonists.

The synthesis and biological evaluation of a series of substituted dipiperidine alcohols are described. Structure-activity relationship studies led to the discovery of potent CCR2 antagonists displaying IC(50) values in the nanomolar or subnanomolar range. The cinnamoyl compounds had higher binding affinities than the corresponding urea analogs.

Synthesis, structure-activity relationship and in vivo antiinflammatory efficacy of substituted dipiperidines as CCR2 antagonists.

A series of substituted dipiperidine compounds have been synthesized and identified as selective CCR2 antagonists. Combining the most favorable substituents led to the discovery of remarkably potent CCR2 antagonists displaying IC50 values in the nanomolar range. Compound 7a had outstanding selectivity over CCR1, CCR3, CCR4, CCR5, CCR6, CCR7, and CCR8 and showed excellent efficacy in adjuvant-induced arthritis model, collagen-induced arthritis model, and allergic asthma model.

Synthesis and biological evaluation of phenyl piperidine derivatives as CCR2 antagonists.

A series of phenyl piperidine derivatives possessing potent and selective CCR2 antagonist activity is reported. Structure-activity relationship (SAR) studies have established that incorporation of a second ring system adjacent to the aryl piperidine plays an important role in determining the CCR2 potency. Both a second piperidine ring and a 1,3-substituted cyclopentylamine have been probed as linkers. For the cyclopentylamine series, the 1S,3R-configuration exhibits much higher affinity for hCCR2 than the 1R,3S-configuration. Compound 3g shows good selectivity over CCR1, CCR3, 5-HT and has an excellent P450 profile.

Potent and selective CC-chemokine receptor-2 (CCR2) antagonists as a potential treatment for asthma.

A number of compounds bearing a quaternary ammonium moiety were found to be antagonists with nanomolar binding affinity for the chemokine receptor-2. The structure-activity relationships in the series are described herein along with some detailed characterization of the interesting compounds.

In vivo activity of a phospholipase C inhibitor, 1-(6-((17beta-3-methoxyestra-1,3,5(10)-trien-17-yl)amino)hexyl)-1H-pyrrole-2,5-dione (U73122), in acute and chronic inflammatory reactions.

To investigate the role of phospholipase C (PLC) in inflammatory processes, we tested 1-(6-((17beta-3-methoxyestra-1,3,5(10)-trien-17-yl)amino)hexyl)-1H-pyrrole-2,5-dione (U73122), a widely used PLC inhibitor, in several in vitro and in vivo assays. We first examined the effects of U73122 on human phospholipase C-beta (PLC-beta) isozymes and found that U73122 significantly inhibited recombinant human PLC-beta2, with an IC(50) of approximately 6 microM. U73122 had little effect on PLC-beta1, PLC-beta3, or PLC-beta4. Consistent with its ability to inhibit PLC-beta2 enzymatic activity, U73122 reduced interleukin-8 and leukotriene B(4)-induced Ca(2+) flux and chemotaxis in human neutrophils in a concentration-dependent manner. In vivo, U73122 blocked carrageenan-induced hind paw edema in rats, carrageenan-induced macrophage and lymphocyte accumulation into subcutaneous chambers in dogs, lipopolysaccharide-induced macrophage, lymphocyte infiltration and prostaglandin E(2) production in a mouse peritonitis model, and 12-O-tetradecanoylphorbol-13-acetate-induced ear edema in mice. These results implicate PLC-dependent signaling pathways in the development of acute and chronic inflammatory responses in vivo.