Hit-to-lead studies: the discovery of potent,orally bioavailable triazolethiol CXCR2 receptor antagonists

A Hit-to-Lead optimisation programme was carried out on the high throughput screening hit, the triazolethiol 1, resulting in the discovery of the potent, orally bioavailable triazolethiol CXCR2 receptor antagonist 45.     

Substituted 2-oxo-azepane derivatives are potent, orally active gamma-secretase inhibitors

A hydroxamic acid screening hit 1 was elaborated to 5,5-dimethyl-2-oxoazepane derivatives exhibiting low nanomolar inhibition of gamma-secretase, a key proteolytic enzyme involved in Alzheimer's disease. Early ADME data showed a high metabolic clearance for the geminal dimethyl analogs which could be overcome by replacement with the bioisosteric geminal difluoro group. Synthesis and structure-activity relationship are discussed and in vivo active compounds are presented.     

Hit-to-Lead studies: the discovery of potent, orally bioavailable thiazolopyrimidine CXCR2 receptor antagonists

A Hit-to-Lead optimisation programme was carried out on a high throughput screening hit, the thiazolopyrimidine 1, resulting in the discovery of the potent, orally bioavailable CXCR2 antagonist 29.     

Hit-to-lead studies on benzimidazole inhibitors of ITK: discovery of a novel class of kinase inhibitors

Benzimidazole 1 was identified as a selective inhibitor of ITK by high throughput screening. Hit-to-lead studies defined the SAR at all three substituents. Reversing the amide linkage at C6 led to 16, with a fivefold improvement of potency. This enhancement is rationalized by the conformational preference of the substituent. A model for the binding of the benzimidazoles to the ATP-binding site of ITK is proposed.     

Discovery of potent and orally active tricyclic-based FBPase inhibitors

With the aim of exploring the effect of tricyclic-based FBPase inhibitors in cells and in vivo, a series of prodrugs of tricyclic phosphonates was designed and synthesized. Introducing prodrug moieties into tricyclic-based phosphonates led to the discovery of prodrug 15c, which strongly inhibited glucose production in monkey hepatocytes. Furthermore, prodrug 15c lowered blood glucose levels in fasted cynomolgus monkeys.     

4-substituted cyclohexyl sulfones as potent, orally active gamma-secretase inhibitors

The protease gamma-secretase plays a pivotal role in the synthesis of pathogenic amyloid-beta in Alzheimer's disease (AD). Here, we report a further extension to a series of cyclohexyl sulfone-based gamma-secretase inhibitors which has allowed the preparation of highly potent compounds which also demonstrate robust Abeta(40) lowering in vivo (e.g., compound 32, MED 1mg/kg p.o. in APP-YAC mice).     

The discovery of potent, selective, and orally active pyrazoloquinolines as PDE10A inhibitors for the treatment of Schizophrenia

High-throughput screening identified a series of pyrazoloquinolines as PDE10A inhibitors. The SAR development led to the discovery of compound 27 as a potent, selective, and orally active PDE10A inhibitor. Compound 27 inhibits MK-801 induced hyperactivity at 3mg/kg with an ED(50) of 4mg/kg and displays a ～6-fold separation between the ED(50) for inhibition of MK-801 induced hyperactivity and hypolocomotion in rats.     

N-benzylimidazole carboxamides as potent, orally active stearoylCoA desaturase-1 inhibitors

A potent, small molecule inhibitor with a favorable pharmacokinetic profile to allow for sustained SCD inhibition in vivo was identified. Starting from a low MW acyl guanidine (5a), identified with a RapidFire High-Throughput Mass Spectrometry (RF-MS) assay, iterative library design was used to rapidly probe the amide and tail regions of the molecule. Singleton synthesis was used to probe core changes. Biological evaluation of a SCD inhibitor (5b) included in vitro potency at SCD-1 and in vivo modulation of the plasma desaturation index (DI) in rats on a low essential fatty acid (LEFA) diet. In addition to dose-dependent decrease in DI, effects on rodent ocular tissue were noted. Therefore, in rat, these SCD inhibitors only recapitulate a portion of phenotype exhibited by the SCD-1 knockout mouse.     

Bicyclic amidine inhibitors of nitric oxide synthase: discovery of perhydro-iminopyrindine and perhydro-iminoquinoline as potent, orally active inhibitors of inducible nitric oxide synthase

Syntheses and nitric oxide synthase inhibitory activity of cyclic amidines containing 5,6- 6,6- and 7,6-fused systems are described. X-ray structure determination facilitated the assignment of the stereochemistry of the most active compounds perhydro-2-iminoisoquinoline (8a) and perhydro-2-iminopyrindine (10a). Both 8a and 10a are very potent inhibitors of iNOS, with excellent selectivity over eNOS and they are orally active in rats with long duration suitable for once or twice a day dosing.     

Development of potent, orally active 1-substituted-3,4-dihydro-2-quinolone glycogen phosphorylase inhibitors

A series of substituted 3,4-dihydro-2-quinolone glycogen phosphorylase inhibitors, which have potential as antidiabetic agents, is described. Initial members of the series showed good enzyme inhibitory potency but poor physical properties. Optimisation of the 1-substituent led to 2,3-dihydroxypropyl compounds which showed good in vitro potency and improved physical properties, together with good DMPK profiles and acute in vivo efficacy in a rat model. X-ray crystallographic data are presented, showing an unexpected variety of binding orientations at the dimer interface site.     

Synthesis and evaluation of thiomannosides,potent and orally active FimH inhibitors

FimH is a type I fimbrial lectin located at the tip of type-1 pili of Gram-negative uropathogenic Escherichia coli (UPEC) guiding its ability to adhere and infect urothelial cells. Accordingly, blocking FimH with small molecule inhibitor is considered as a promising new therapeutic alternative to treat urinary tract infections caused by UPEC. Herein, we report that compounds having the S-glycosidic bond (thiomannosides) had improved metabolic stability and plasma exposures when dosed orally. Especially compound 5h showed the potential to inhibit biofilm formation and also to disrupt the preformed biofilm. And compound 5h showed prophylactic effect in UTI model in mice.     

SAR in the alkoxy lactone series: the discovery of DFP, a potent and orally active COX-2 inhibitor.

Extensive SAR has been established in the alkoxy lactone series and this has lead to the discovery of DFP (5,5-dimethyl-3-(2-propoxy)-4-methanesulfonylphenyl)-2(5H)-furanon e), a potent COX-2 inhibitor exhibiting in vivo efficacy in all models studied.     

5-heteroatom substituted pyrazoles as canine COX-2 inhibitors. Part 1: Structure-activity relationship studies of 5-alkylamino pyrazoles and discovery of a potent, selective, and orally active analog

Structure-activity relationship (SAR) studies of the novel 2-[3-di and trifluoromethyl-5-alkylamino pyrazo-1-yl]-5-methanesulfonyl (SO(2)Me)/sulfamoyl (SO(2)NH(2))-pyridine derivatives for canine COX enzymes are described. The studies led to the identification of 2e as lead with potent in vitro activity, selectivity, and in vivo activity in dogs and cats.     

Discovery of triazines as potent,selective and orally active PDE4 inhibitors

Expanding on HTS hit 4 afforded a series of [1,3,5]triazine derivatives as novel PDE4 inhibitors. The SAR development and optimization process with the emphasis on ligand efficiency and physicochemical properties led to the discovery of compound 44 as a potent, selective and orally active PDE4 inhibitor.     

Identification of 2,3-disubstituted pyridines as potent,orally active PDE4 inhibitors

A series of 2,3-disubstituted pyridines were synthesized and evaluated for their PDE4 inhibitory activity. We successfully modified undesirable cyano group of initial lead compound 2 to 4-pyridyl group with improvement of in vitro efficacy and optimized the position of nitrogen atoms in pyridine moiety and alkylene linker. The most potent compound showed significant efficacy in animal models of asthma and inflammation.     

Substituted phenanthrene imidazoles as potent, selective, and orally active mPGES-1 inhibitors

Phenanthrene imidazole 3 (MF63) has been identified as a novel potent, selective, and orally active mPGES-1 inhibitor. This new series was developed by lead optimization of a hit from an internal HTS campaign. Compound 3 is significantly more potent than the previously reported indole carboxylic acid 1 with an A549 whole cell IC₅₀ of 0.42 μM (50% FBS) and a human whole blood IC₅₀ of 1.3 μM. It exhibited a significant analgesic effect in a guinea pig hyperalgesia model when orally dosed at 30 and 100 mg/kg.     

Neutral 5-substituted 4-anilinoquinazolines as potent, orally active inhibitors of erbB2 receptor tyrosine kinase

Neutral 5-substituted 4-anilinoquinazolines addressed high in vivo clearance and phospholipidosis associated with previous basic compounds. A representative compound 8a inhibited tumor growth in a mouse xenograft model when co-administered with the cytochrome P450 inhibitor 1-aminobenzotriazole (ABT), and data are consistent with pharmacology primarily reflecting inhibition of erbB2 receptor tyrosine kinase.     

Neutral 5-substituted 4-indazolylaminoquinazolines as potent, orally active inhibitors of erbB2 receptor tyrosine kinase

We have identified a new series of C-5 substituted indazolylaminoquinazolines as potent erbB2 kinase inhibitors. The lead compound 22 showed excellent in vitro potency, good physical properties, acceptable oral pharmacokinetics in rat and dog, and low human in vitro clearance. It showed at least equivalent activity dose for dose compared to lapatinib in various erbB2- or EGFR-driven xenograft models after chronic oral administration.     

Arylphthalazines as potent,and orally bioavailable inhibitors of VEGFR-2

A series of arylphthalazine derivatives were synthesized and evaluated as antagonists of VEGF receptor II (VEGFR-2). IM-094482 57, which was prepared in two steps from commercially available starting materials, was found to be a potent inhibitor of VEGFR-2 in enzymatic, cellular and mitogenic assays (comparable activity to ZD-6474). Additionally, 57 inhibited the related receptor, VEGF receptor I (VEGFR-1), and showed excellent exposure when dosed orally to female CD-1 mice.     

The discovery of potent,selective, and orally bioavailable PDE9 inhibitors as potential hypoglycemic agents

Starting from a non-selective pyrazolo-pyrimidone lead, the sequential use of parallel medicinal chemistry and directed synthesis led to the discovery of potent, highly selective, and orally bioavailable PDE9 inhibitors. The availability of these tools allowed for a thorough evaluation of the therapeutic potential of PDE9 inhibition.