Discovery of thiochroman and chroman derivatives as pure antiestrogens and their structure-activity relationship

In order to develop pure antiestrogens, a series of 7-hydroxy-3-(4-hydroxyphenyl)-3-methylchroman and 7-hydroxy-3-(4-hydroxyphenyl)-3-methylthiochroman derivatives with sulfoxide containing side chains at the 4-position were designed, synthesized, and evaluated. Among them, compounds 14b and 24b functioned as pure antiestrogens with the ability to downregulate ER, and their in vitro and in vivo antiestrogen activities were similar to those of ICI182,780. In addition, the structure-activity relationship indicated that the (3RS,4RS)-configuration between the 3- and 4-position, the methyl group at the 3-position, the 9-methylene chain between the scaffold and the sulfoxide moiety, and the terminal perfluoroalkyl moiety play an important role in increasing estrogen receptor binding and oral antiestrogen activities.     

Newly discovered orally active pure antiestrogens

In order to develop orally active pure antiestrogens, we incorporated the carboxy-containing side chains into the 7alpha-position of the steroid scaffold and found that 17-keto derivative CH4893237 (12b) functioned as a pure antiestrogen with its oral activity much superior to clinically used pure antiestrogen, ICI182,780. Results from the pharmacokinetic evaluation indicated that the potent antiestrogen activity at oral dosing in mice attributed to both improved absorption from the intestinal wall and metabolic stability in liver.     

Discovery and structure-activity relationships of new steroidal compounds bearing a carboxy-terminal side chain as androgen receptor pure antagonists

Lead optimization of CH4892280 (4), an androgen receptor (AR) pure antagonist, was investigated. Compounds 6 and 7, which have a carboxylic acid at the end of the side chain at the position 7alpha of dihydrotestosterone (DHT), showed partial agonistic activities in reporter gene assay (RGA). Conversion of the steroidal core structure to 17alpha-methyltestosterone gave compound 14, which showed weak pure antagonistic activity. Optimization of the side chain by the insertion of a phenyl ring led to compounds 22 and 28-30, which showed pure antagonistic activities at submicromolar concentrations. The structure-activity relationships were clarified.     

Discovery of novel diarylketoxime derivatives as selective and orally active melanin-concentrating hormone 1 receptor antagonists

Optimization of the lead 2a led to the identification of a novel diarylketoxime class of melanin-concentrating hormone 1 receptor (MCH-1R) antagonists. Our focus was directed toward improvement of hERG activity and metabolic stability. The representative derivative 4b showed potent and dose-dependent body weight reduction in diet-induced obese (DIO) C57BL/6J mice after oral administration. The synthesis and structure–activity relationships of the novel diarylketoxime MCH-1R antagonists are described.     

Discovery of novel aminobenzisoxazole derivatives as orally available factor IXa inhibitors

Using structure based drug design, novel aminobenzisoxazoles as coagulation factor IXa inhibitors were designed and synthesized. Highly selective inhibition of FIXa over FXa was demonstrated. Anticoagulation profile of selected compounds was evaluated by aPTT and PT tests. In vitro ADMET and pharmacokinetic (PK) profiles were also evaluated.     

Discovery of furan-2-carbohydrazides as orally active glucagon receptor antagonists

Furan-2-carbohydrazides were found as orally active glucagon receptor antagonists. Starting from the hit compound 5, we successfully determined the structure activity relationships of a series of derivatives obtained by modifying the acidity of the phenol. We identified the ortho-nitrophenol as a good scaffold for glucagon receptor inhibitory activity. Our efforts have led to the discovery of compound 7l as a potent glucagon receptor antagonist with good bioavailability and satisfactory long half-life.     

Discovery of DS42450411 as a potent orally active hepcidin production inhibitor: Design and optimization of novel 4-aminopyrimidine derivatives

Hepcidin has emerged as the central regulatory molecule in systemic iron homeostasis. The inhibition of hepcidin may be a favorable strategy for the treatment of anemia of chronic disease. Here, we have reported the design, synthesis, and structure–activity relationships (SAR) of a series of 4-aminopyrimidine compounds as inhibitors of hepcidin production. The optimization study of 1 led to the design of a potent and bioavailable inhibitor of hepcidin production, 34 (DS42450411), which showed serum hepcidin-lowering effects in a mouse model of interleukin-6-induced acute inflammation.     

Ketene aminal-based lactam derivatives as a novel class of orally active FXa inhibitors

N,N′-Disubstituted ketene aminals are good bioisosteres of thiourea functional groups. We report the design and synthesis of a novel class of ketene aminal-based lactam derivatives as potent and orally active FXa inhibitors.     

Discovery of benzimidazole derivatives as orally active renin inhibitors: Optimization of 3,5-disubstituted piperidine to improve pharmacokinetic profile

We previously identified 2-tert-butyl-4-[(3-methoxypropyl)amino]-N-(2-methylpropyl)-N-[(3S,5R)-5-(morpholin-4-ylcarbonyl)piperidin-3-yl]pyrimidine-5-carboxamide 3 as a potent renin inhibitor. Since 3 showed unacceptably low bioavailability (BA) in rats, structural modification, using SBDD and focused on physicochemical properties was conducted to improve its PK profile while maintaining renin inhibitory activity. Conversion of the amino group attached at the 4-position of pyrimidine to methylene group improved PK profile and decreased renin inhibitory activity. New central cores with carbon side chains were explored to improve potency. We had designed a series of 5-membered azoles and fused heterocycles that interacted with the lipophilic S3 pocket. In the course of modification, renin inhibitory activity was enhanced by the formation of an additional hydrogen bonding with the hydroxyl group of Thr77. Consequently, a series of novel benzimidazole derivatives were discovered as potent and orally bioavailable renin inhibitors. Among those, compound 13 exhibited more than five-fold of plasma renin inhibition than aliskiren in cynomolgus monkeys at dose ratio.     

Discovery of new diphenyloxazole derivatives containing a pyrrolidine ring: orally active prostacyclin mimetics. Part 2

Synthetic and biological evaluation of novel diphenyloxazole derivatives containing a pyrrolidine ring, as a prostacyclin mimetic without the PG skeleton, are described. Asymmetric reduction of a ketone using a chiral Ru complex and reductive amination by NaBH(4) produces four isomers of the tetrahydronaphthalene ring and the pyrrolidine ring with high stereoselectivity. FR193262 (4), (R,R)-diphenyloxazolyl pyrrolidine derivative, displays high potency and agonist efficacy at the IP receptor and has good bioavailability in rats and dogs.     

Discovery of potent and orally active MTP inhibitors as potential anti-obesity agents

We have successfully identified a number of novel MTP inhibitors with single digit nanomolar potency. Analogues 10aq and 10dq demonstrated in vivo efficacy in a murine gut retention assay.     

Discovery of novel tetrahydroisoquinoline derivatives as orally active N-type calcium channel blockers with high selectivity for hERG potassium channels

N-type calcium channels represent a promising target for the treatment of neuropathic pain. The selective N-type calcium channel blocker ziconotide ameliorates severe chronic pain but has a narrow therapeutic window and requires intrathecal administration. We identified tetrahydroisoquinoline derivative 1a as a novel potent N-type calcium channel blocker. However, this compound also exhibited potent inhibitory activity against hERG channels. Structural optimizations led to identification of (1S)-(1-cyclohexyl-3,4-dihydroisoquinolin-2(1H)-yl)-2-{[(1-hydroxycyclohexyl)methyl]amino}ethanone ((S)-1h), which exhibited high selectivity for hERG channels while retaining potency for N-type calcium channel inhibition. (S)-1h went on to demonstrate in vivo efficacy as an orally available N-type calcium channel blocker in a rat spinal nerve ligation model of neuropathic pain.     

Discovery of aminopyridines substituted with benzoxazole as orally active c-Met kinase inhibitors

We report the synthesis and biological evaluation of aminopyridines substituted with benzoxazole. The SAR of the aminopyridines was explored to improve the inhibitory activity against c-Met and to decrease hERG affinity. These studies led to the discovery of amide 24 which showed good c-Met inhibitory potency, low affinity to hERG and favorable pharmacokinetic properties in rats.     

Discovery and biological evaluation of novel 4-amino-2-phenylpyrimidine derivatives as potent and orally active GPR119 agonists

Novel 4-amino-2-phenylpyrimidine derivatives were synthesized and evaluated as GPR119 agonists. Optimization of the substituents on the phenyl ring at the 2-position and the amino group at the 4-position led to the identification of 3,4-dihalogenated and 2,4,5-trihalogenated phenyl derivatives showing potent GPR119 agonistic activity. The advanced analog (2R)-3-{[2-(4-chloro-2,5-difluorophenyl)-6-ethylpyrimidin-4-yl]amino}propane-1,2-diol (24g) was found to improve glucose tolerance at 1mg/kg po in mice and to show excellent pharmacokinetic profiles in mice and monkeys. Compound 24g also showed an excellent antidiabetic effect in diabetic kk/Ay mice after one week of single daily treatment. These results demonstrate that novel GPR119 agonist 24g improves glucose tolerance not only by enhancing glucose-dependent insulin secretion but also by preserving pancreatic β-cell function.     

Discovery of DS28120313 as a potent orally active hepcidin production inhibitor: Design and optimization of novel 4,6-disubstituted indazole derivatives

Hepcidin has emerged as the central regulatory molecule in systemic iron homeostasis, and its inhibition could be a favorable strategy for treating anemia of chronic disease (ACD). Here, we report the design, synthesis and structure–activity relationships (SAR) of a series of 4,6-disubstituted indazole compounds as hepcidin production inhibitors. The optimization study of multi-kinase inhibitor 1 led to the design of a potent and bioavailable hepcidin production inhibitor, 32 (DS28120313), which showed serum hepcidin-lowering effects in an interleukin-6-induced acute inflammatory mouse model.     

Synthesis of novel 3-carboxamide-benzocoumarin derivatives as orally active antithrombotic agents

In an effort to develop potent antithrombotic agents, a series of novel 3-carboxamide-benzocoumarin derivatives were synthesized and screened for their in vivo antithrombotic activity. Among 20 compounds tested, the compound 12b showed the most promising antithrombotic activity which was comparable with clinically used aspirin or warfarin, but, at variance with these standard drugs, 12b did not exhibit the increased bleeding time, suggesting its potential as a novel antithrombotic agent.     

Discovery of diphenylcarbamate derivatives as highly potent and selective IP receptor agonists: orally active prostacyclin mimetics. Part 3

The new classes of diphenylcarbamate derivatives with a tetrahydronaphthalene skeleton as highly potent and selective IP agonists have been discovered. The optimized diphenylcarbamate type compound FK-788: (R)-4 exhibited potent antiaggregative potency with an IC50 of 18 nM and high binding affinity for the human recombinant IP receptor with K(i) values of 20 nM and selectivity for human IP over all other members of the human prostanoid receptor family. Compound (R)-4 was shown to exhibit good pharmacokinetic properties in rats and dogs, and also good bioavailability in healthy volunteers.     

Discovery and synthesis of novel substituted benzocoumarins as orally active lipid modulating agents

The synthesis of a series of benzocoumarin keto-enamine schiff bases is reported. The novel compounds were evaluated for their antihyperlipidemic activity in the hyperlipidemic hamster model. The compound 11 at a dose of 10 mg/kg body weight significantly lowered the plasma triglyceride levels (TG) by 70%, total cholesterol (TC) by 47%, accompanied by an increase in HDL-C/TC ratio by 80% in hyperlipidemic hamsters to a greater degree than the reference drugs atorvastatin and lovastatin.     

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.     

Discovery of 3-aryl-3-ethoxypropanoic acids as orally active GPR40 agonists

The G protein-coupled receptor 40 (GPR40) mediates enhancement of glucose-stimulated insulin secretion in pancreatic β cells. The GPR40 agonist has been attracting attention as a novel insulin secretagogue with glucose dependency for the treatment of type 2 diabetes. The optimization study of compound 1 led to a potent and bioavailable GPR40 agonist 24, which showed insulin secretion and glucose lowering effects in rat OGTT. Compound 24 is a potential lead compound for a novel insulin secretagogue with a low risk of hypoglycemia.