ABSTRACT
The selective inhibition of RET kinase as a treatment for relevant cancer types including lung adenocarcinoma has garnered considerable interest in recent years and prompted a variety of efforts toward the discovery of small-molecule therapeutics. Hits uncovered via the analysis of archival kinase data ultimately led to the identification of a promising pyrrolo[2,3-d]pyrimidine scaffold. The optimization of this pyrrolo[2,3-d]pyrimidine core resulted in compound 1, which demonstrated potent in vitro RET kinase inhibition and robust in vivo efficacy in RET-driven tumor xenografts upon multiday dosing in mice. The administration of 1 was well-tolerated at established efficacious doses (10 and 30 mg/kg, po, qd), and plasma exposure levels indicated a minimal risk of KDR or hERG inhibition in vivo, as evaluated by Miles assay and free plasma concentrations, respectively.
ABSTRACT
Antagonists of the corticotropin-releasing factor (CRF) neuropeptide may prove effective in treating stress and anxiety related disorders. In an effort to identify antagonists with improved physico-chemical properties a new series of CRF(1) antagonists were designed to substitute the propyl groups at the C7 position of the pyrazolo[1,5-a]pyrimidine core of 1 with heterocycles. Compound (S)-8d was identified as a high affinity ligand with a pK(i) value of 8.2 and a functional CRF(1) antagonist with pIC(50) value of 7.0 in the in vitro CRF ACTH production assay.
Subject(s)
Azabicyclo Compounds/chemistry , Oxadiazoles/chemistry , Pyrazoles/chemistry , Pyridines/chemistry , Receptors, Corticotropin-Releasing Hormone/antagonists & inhibitors , Azabicyclo Compounds/chemical synthesis , Azabicyclo Compounds/pharmacokinetics , Humans , Microsomes, Liver/metabolism , Oxadiazoles/chemical synthesis , Oxadiazoles/pharmacokinetics , Protein Binding , Receptors, Corticotropin-Releasing Hormone/genetics , Receptors, Corticotropin-Releasing Hormone/metabolism , Recombinant Proteins/antagonists & inhibitors , Recombinant Proteins/genetics , Recombinant Proteins/metabolismABSTRACT
RET (REarranged during Transfection) kinase gain-of-function aberrancies have been identified as potential oncogenic drivers in lung adenocarcinoma, along with several other cancer types, prompting the discovery and assessment of selective inhibitors. Internal mining and analysis of relevant kinase data informed the decision to investigate a pyrazolo[1,5-a]pyrimidine scaffold, where subsequent optimization led to the identification of compound WF-47-JS03 (1), a potent RET kinase inhibitor with >500-fold selectivity against KDR (Kinase insert Domain Receptor) in cellular assays. In subsequent mouse in vivo studies, compound 1 demonstrated effective brain penetration and was found to induce strong regression of RET-driven tumor xenografts at a well-tolerated dose (10 mg/kg, po, qd). Higher doses of 1, however, were poorly tolerated in mice, similar to other pyrazolo[1,5-a]pyrimidine compounds at or near the efficacious dose, and indicative of the narrow therapeutic windows seen with this scaffold.
ABSTRACT
Direct pharmacological inhibition of RAS has remained elusive, and efforts to target CRAF have been challenging due to the complex nature of RAF signaling, downstream of activated RAS, and the poor overall kinase selectivity of putative RAF inhibitors. Herein, we describe 15 (LXH254, Aversa, R.; et al. Int. Patent WO2014151616A1, 2014), a selective B/C RAF inhibitor, which was developed by focusing on drug-like properties and selectivity. Our previous tool compound, 3 (RAF709; Nishiguchi, G. A.; et al. J. Med. Chem. 2017, 60, 4969), was potent, selective, efficacious, and well tolerated in preclinical models, but the high human intrinsic clearance precluded further development and prompted further investigation of close analogues. A structure-based approach led to a pyridine series with an alcohol side chain that could interact with the DFG loop and significantly improved cell potency. Further mitigation of human intrinsic clearance and time-dependent inhibition led to the discovery of 15. Due to its excellent properties, it was progressed through toxicology studies and is being tested in phase 1 clinical trials.
Subject(s)
Antineoplastic Agents/chemistry , Drug Discovery/methods , Mutation/genetics , Protein Kinase Inhibitors/chemistry , Proto-Oncogene Proteins B-raf/antagonists & inhibitors , Proto-Oncogene Proteins B-raf/genetics , Animals , Antineoplastic Agents/pharmacology , Drug Design , Drug Discovery/trends , Humans , Molecular Docking Simulation/methods , Molecular Docking Simulation/trends , Mutation/drug effects , Protein Kinase Inhibitors/pharmacology , Xenograft Model Antitumor Assays/methodsABSTRACT
The discovery and synthesis of a series of (dimethoxyphenoxy)alkylamino acetamides as orexin-2 receptor antagonists from a small-molecule combinatorial library using a high-throughput calcium mobilization functional assay (HEK293-human OX2-R cell line) is described. Active compounds show a good correlation between high-throughput single concentration screening data and measured IC(50)s. Specific examples exhibit IC(50) values of approximately 20 nM using human orexin A as the peptide agonist for the orexin-2 receptor.
Subject(s)
Acetamides/chemical synthesis , Chemistry, Pharmaceutical/methods , Intracellular Signaling Peptides and Proteins/chemistry , Neuropeptides/chemistry , Receptors, G-Protein-Coupled/antagonists & inhibitors , Receptors, Neuropeptide/antagonists & inhibitors , Acetamides/chemistry , Calcium/chemistry , Cell Line , Combinatorial Chemistry Techniques , Drug Design , Humans , Inhibitory Concentration 50 , Models, Chemical , Mutation , Orexin Receptors , Orexins , TemperatureABSTRACT
In this report, the design and synthesis of a series of pyrimidine based adenosine A(2A) antagonists are described. The strategy and outcome of expanding SAR exploration to attenuate hERG and improve selectivity over A(1) are discussed. Compound 33 exhibited excellent potency, selectivity over A(1), and reduced hERG liability.
Subject(s)
Adenosine A2 Receptor Antagonists , DNA-Binding Proteins/antagonists & inhibitors , Pyrimidines/pharmacology , Trans-Activators/antagonists & inhibitors , Cell Line , Cytochrome P-450 CYP3A/metabolism , Cytochrome P-450 CYP3A Inhibitors , Drug Design , Humans , Kinetics , Pyrimidines/chemical synthesis , Pyrimidines/chemistry , Receptor, Adenosine A2A/metabolism , Structure-Activity Relationship , Transcriptional Regulator ERGABSTRACT
In this report, the strategy and outcome of expanding SAR exploration to improve solubility and metabolic stability are discussed. Compound 35 exhibited excellent potency, selectivity over A(1) and improved solubility of >4 mg/mL at pH 8.0. In addition, compound 35 had good metabolic stability with a scaled intrinsic clearance of 3 mL/min/kg (HLM) and demonstrated efficacy in the haloperidol induced catalepsy model.
Subject(s)
Adenosine A2 Receptor Antagonists , Aminopyridines/chemistry , Chemistry, Pharmaceutical/methods , Pyrimidines/chemical synthesis , Drug Design , Haloperidol/chemistry , Humans , Hydrogen-Ion Concentration , Inhibitory Concentration 50 , Models, Chemical , Parkinson Disease/therapy , Protein Binding , Pyrimidines/chemistry , Pyrimidines/pharmacology , Receptor, Adenosine A1/chemistry , Receptor, Adenosine A2A/chemistry , Solubility , Structure-Activity RelationshipABSTRACT
A series of N-pyrimidinyl-2-phenoxyacetamide adenosine A(2A) antagonists is described. SAR studies led to compound 14 with excellent potency (K(i) = 0.4 nM), selectivity (A(1)/A(2A) > 100), and efficacy (MED 10 mg/kg p.o.) in the rat haloperidol-induced catalepsy model for Parkinson's disease.
Subject(s)
Adenosine A2 Receptor Antagonists , Antiparkinson Agents/chemical synthesis , Catalepsy/prevention & control , Parkinson Disease/physiopathology , Phenoxyacetates/chemical synthesis , Pyrimidines/chemical synthesis , Administration, Oral , Animals , Antiparkinson Agents/pharmacology , Catalepsy/chemically induced , Cytochrome P-450 CYP2D6/metabolism , Cytochrome P-450 CYP2D6 Inhibitors , Cytochrome P-450 CYP3A , Cytochrome P-450 Enzyme Inhibitors , Cytochrome P-450 Enzyme System/metabolism , Electrophysiology , Ether-A-Go-Go Potassium Channels/antagonists & inhibitors , Haloperidol/toxicity , Humans , Molecular Structure , Phenoxyacetates/chemistry , Phenoxyacetates/pharmacology , Pyrimidines/chemistry , Pyrimidines/pharmacology , Rats , Structure-Activity RelationshipABSTRACT
RAS oncogenes have been implicated in >30% of human cancers, all representing high unmet medical need. The exquisite dependency on CRAF kinase in KRAS mutant tumors has been established in genetically engineered mouse models and human tumor cells. To date, many small molecule approaches are under investigation to target CRAF, yet kinase-selective and cellular potent inhibitors remain challenging to identify. Herein, we describe 14 (RAF709) [ Aversa , Biaryl amide compounds as kinase inhibitors and their preparation . WO 2014151616, 2014 ], a selective B/C RAF inhibitor, which was developed through a hypothesis-driven approach focusing on drug-like properties. A key challenge encountered in the medicinal chemistry campaign was maintaining a balance between good solubility and potent cellular activity (suppression of pMEK and proliferation) in KRAS mutant tumor cell lines. We investigated the small molecule crystal structure of lead molecule 7 and hypothesized that disruption of the crystal packing would improve solubility, which led to a change from N-methylpyridone to a tetrahydropyranyl oxy-pyridine derivative. 14 proved to be soluble, kinase selective, and efficacious in a KRAS mutant xenograft model.
Subject(s)
2,2'-Dipyridyl/analogs & derivatives , Antineoplastic Agents/pharmacology , Benzamides/pharmacology , raf Kinases/antagonists & inhibitors , ras Proteins/genetics , 2,2'-Dipyridyl/chemistry , 2,2'-Dipyridyl/pharmacology , Animals , Antineoplastic Agents/chemistry , Antineoplastic Agents/pharmacokinetics , Benzamides/chemistry , Crystallography, X-Ray , Dogs , Drug Design , Drug Discovery , Drug Stability , Humans , Inhibitory Concentration 50 , Mice , Molecular Targeted Therapy , Neoplasms/drug therapy , Neoplasms/genetics , Proto-Oncogene Proteins B-raf/chemistry , Proto-Oncogene Proteins p21(ras)/genetics , Rats , Structure-Activity Relationship , Xenograft Model Antitumor AssaysABSTRACT
In a previous report we demonstrated that merging together key structural elements present in an AT(1) receptor antagonist (1, irbesartan) with key structural elements in a biphenylsulfonamide ET(A) receptor antagonist (2) followed by additional optimization provided compound 3 as a dual-action receptor antagonist (DARA), which potently blocked both AT(1) and ET(A) receptors. Described herein are our efforts directed toward improving both the pharmacokinetic profile as well as the AT(1) and ET(A) receptor potency of 3. Our efforts centered on modifying the 2'-side chain of 3 and examining the isoxazolylsulfonamide moiety in 3. This effort resulted in the discovery of 7 as a highly potent second-generation DARA. Compound 7 also showed substantially improved pharmacokinetic properties compared to 3. In rats, DARA 7 reduced blood pressure elevations caused by intravenous infusion of Ang II or big ET-1 to a greater extent and with longer duration than DARA 3 or AT(1) or ET(A) receptor antagonists alone. Compound 7 clearly demonstrated superiority over irbesartan (an AT(1) receptor antagonist) in the normal SHR model of hypertension in a dose-dependent manner, demonstrating the synergy of AT(1) and ET(A) receptor blockade in a single molecule.
Subject(s)
Angiotensin II Type 1 Receptor Blockers/chemistry , Angiotensin II Type 1 Receptor Blockers/pharmacology , Endothelin A Receptor Antagonists , Isoxazoles/chemistry , Isoxazoles/pharmacology , Receptor, Angiotensin, Type 1/drug effects , Sulfonamides/chemistry , Sulfonamides/pharmacology , Administration, Oral , Angiotensin II/pharmacology , Angiotensin II Type 1 Receptor Blockers/pharmacokinetics , Animals , Antihypertensive Agents/chemistry , Antihypertensive Agents/pharmacology , Biological Availability , Biphenyl Compounds/chemistry , Biphenyl Compounds/pharmacology , Dogs , Humans , Hypertension/drug therapy , Irbesartan , Isoxazoles/pharmacokinetics , Macaca fascicularis , Male , Rats , Rats, Inbred SHR , Structure-Activity Relationship , Sulfonamides/pharmacokinetics , Tetrazoles/chemistry , Tetrazoles/pharmacologyABSTRACT
The synthesis and SAR studies of tricyclic imidazo[4,5-b]pyridin-2-ones as human corticotropin-releasing factor receptor (CRF(1)) antagonists are discussed herein. Compound 16g was identified as a functional antagonist that inhibited CRF-stimulated cyclic adenosine monophosphate production and CRF-induced adrenocorticotrophic hormone release. Pharmacokinetics studies in rats showed that 16g was orally bioavailable, had good brain penetration, and had a moderate half-life. In our effort to identify CRF(1) antagonists with improved pharmacokinetics properties, 16g exhibited a favorably lower volume of distribution.
Subject(s)
Heterocyclic Compounds, 3-Ring/chemical synthesis , Imidazoles/chemical synthesis , Pyridines/chemical synthesis , Receptors, Corticotropin-Releasing Hormone/antagonists & inhibitors , Administration, Oral , Adrenocorticotropic Hormone/blood , Animals , Blood-Brain Barrier/metabolism , CHO Cells , Corticotropin-Releasing Hormone/pharmacology , Cricetinae , Cricetulus , Cyclic AMP/antagonists & inhibitors , Cyclic AMP/biosynthesis , Drug Design , Heterocyclic Compounds, 3-Ring/pharmacokinetics , Heterocyclic Compounds, 3-Ring/pharmacology , Humans , Imidazoles/pharmacokinetics , Imidazoles/pharmacology , Injections, Intravenous , Male , Pyridines/pharmacokinetics , Pyridines/pharmacology , Radioligand Assay , Rats , Rats, Sprague-Dawley , Stereoisomerism , Structure-Activity RelationshipABSTRACT
The ET(A) receptor antagonist (2) (N-(3,4-dimethyl-5-isoxazolyl)-4'-(2-oxazolyl)-[1,1'-biphenyl]-2-sulfonamide, BMS-193884) shares the same biphenyl core as a large number of AT(1) receptor antagonists, including irbesartan (3). Thus, it was hypothesized that merging the structural elements of 2 with those of the biphenyl AT(1) antagonists (e.g., irbesartan) would yield a compound with dual activity for both receptors. This strategy led to the design, synthesis, and discovery of (15) (4'-[(2-butyl-4-oxo-1,3-diazaspiro[4.4]non-1-en-3-yl)methyl]-N-(3,4-dimethyl-5-isoxazolyl)-2'-[(3,3-dimethyl-2-oxo-1-pyrrolidinyl)methyl]-[1,1'-biphenyl]-2-sulfonamide, BMS-248360) as a potent and orally active dual antagonist of both AT(1) and ET(A) receptors. Compound 15 represents a new approach to treating hypertension.
Subject(s)
Angiotensin II/metabolism , Angiotensin Receptor Antagonists , Endothelin Receptor Antagonists , Isoxazoles/chemical synthesis , Sulfonamides/chemical synthesis , Animals , Antihypertensive Agents/chemical synthesis , Antihypertensive Agents/chemistry , Antihypertensive Agents/pharmacology , Blood Pressure/drug effects , CHO Cells , Cricetinae , Crystallography, X-Ray , Isoxazoles/chemistry , Isoxazoles/pharmacology , Molecular Structure , Radioligand Assay , Rats , Receptor, Angiotensin, Type 1 , Receptor, Endothelin A , Structure-Activity Relationship , Sulfonamides/chemistry , Sulfonamides/pharmacologyABSTRACT
We report our synthesis of the C(26)-C(37) fragment of serine/threonine protein phosphatase PP1 and PP2A inhibitor calyculin C (1). Outlined in this paper are synthetic approaches to the two components based on disconnection at the C(33)-N(3) amide bond. We report the successful synthesis of the C(33)-C(37) aza-sugar derived from D-lyxose which was coupled onto a C(26)-C(32) aminooxazole originating from L-pyroglutamic acid. Elaboration of the resulting amide to a fully deprotected C(26)-C(37) fragment of calyculin C completed our synthesis. This provided an appropriate phosphonium salt for use in a Wittig olefination for joining both halves of the natural product.
ABSTRACT
In the present article, we report on a strategy to improve the physical properties of a series of small molecule human adenosine 2A (hA2A) antagonists. One of the aromatic rings typical of this series of antagonists is replaced with a series of aliphatic groups, with the aim of disrupting crystal packing of the molecule to lower the melting point and in turn to improve the solubility. Herein, we describe the SAR of a new series of water-soluble 2,4,6-trisubstituted pyrimidines where R1 is an aromatic heterocycle, R2 is a short-chain alkyl amide, and the typical R3 aromatic heterocyclic substituent is replaced with an aliphatic amino substituent. This approach significantly enhanced aqueous solubility and lowered the log P of the system to provide molecules without significant hERG or CYP liabilities and robust in vivo efficacy.
Subject(s)
Acetamides/therapeutic use , Adenosine A2 Receptor Antagonists , Pyrimidines/therapeutic use , Acetamides/chemical synthesis , Adenosine A1 Receptor Antagonists , Animals , Behavior, Animal/drug effects , Catalepsy/chemically induced , Catalepsy/drug therapy , Drug Synergism , Haloperidol , Humans , Pyrimidines/chemical synthesis , Rats , Rotation , Solubility , Structure-Activity RelationshipABSTRACT
Antagonists of the corticotropin releasing factor (CRF or CRH) receptor have shown promise for the treatment of anxiety, depression, and irritable bowel syndrome. In the present article, medicinal chemistry developments surrounding small molecule CRF receptor antagonists are reviewed, focusing on publications and patents from mid-2004 through the first quarter of 2006. While the CRF type 2 receptor remains an intractable target, incremental progress has been made in the search for drug-like antagonists of the CRF type 1 receptor. Most recent work has not ventured far from previously-established pharmacophoric topologies. A common theme in recent patent disclosures is the addition of novel polar substituents to known heterocyclic core structures to reduce overall lipophilicity. New disclosures of pharmacokinetic (PK) data for several series of antagonists reveal that achieving appropriate PK remains a challenge for the field. The recent publication of selection patents and patents relating to salt and crystal forms of particular compounds suggests that several second generation compounds are nearing or have entered clinical development.
Subject(s)
Anti-Anxiety Agents/chemistry , Antidepressive Agents/chemistry , Receptors, Corticotropin-Releasing Hormone/antagonists & inhibitors , Anti-Anxiety Agents/pharmacokinetics , Anti-Anxiety Agents/pharmacology , Antidepressive Agents/pharmacokinetics , Antidepressive Agents/pharmacology , Anxiety/drug therapy , Chemistry, Pharmaceutical , Depression/drug therapy , Irritable Bowel Syndrome/drug therapy , Structure-Activity RelationshipABSTRACT
4-Acetylamino-2-(3,5-dimethylpyrazol-1-yl)-pyrimidines bearing substituted pyridyl groups as C-6 substituents were prepared as selective adenosine hA2A receptor antagonists for the treatment of Parkinson's disease. The 5-methoxy-3-pyridyl derivative 6g (hA2A Ki 2.3 nM, hA1 Ki 190 nM) was orally active at 3 mg/kg in a rat HIC model but exposure was poor in nonrodent species, presumably due to poor aqueous solubility. Follow-on compound 16a (hA2A Ki 0.83 nM, hA1 Ki 130 nM), bearing a 6-(morpholin-4-yl)-2-pyridyl substituent at C-6, had improved solubility and was orally efficacious (3 mg/kg, HIC) but showed time-dependent cytochrome P450 3A4 inhibition, possibly related to morpholine ring metabolism. Compound 16j (hA2A Ki 0.44 nM, hA1 Ki 80 nM), bearing a 6-(4-methoxypiperidin-1-yl)-2-pyridyl substituent at C-6, was sparingly soluble but had good oral exposure in rodent and nonrodent species, had no cytochrome P450 or human ether-a-go-go related gene channel issues, and was orally efficacious at 1 mg/kg in HIC and at 3 mg/kg for potentiation of l-dopa-induced contralateral rotations in 6-hydroxydopamine-lesioned rats.
Subject(s)
Adenosine A2 Receptor Antagonists , Parkinson Disease/drug therapy , Pyrazoles/pharmacology , Pyrimidines/pharmacology , Animals , Catalepsy/chemically induced , Catalepsy/drug therapy , Disease Models, Animal , Drug Design , Drug Evaluation, Preclinical , Haloperidol , Humans , Ligands , Molecular Structure , Pyrazoles/chemical synthesis , Pyrazoles/chemistry , Pyrimidines/chemical synthesis , Pyrimidines/chemistry , Rats , Stereoisomerism , Structure-Activity RelationshipABSTRACT
The construction of triazacyclopenta[cd]pentalene diesters 6 by the reaction of dihydropyrrole alpha-ketoesters 3 with acylated hydrazines was evaluated further as a potential central strategic step in the total syntheses of complex guanidine alkaloids such as palau'amine and styloguanidine. Successful cyclocondensations were realized with acid-stable 2,2,2-trichloroethyl carbazate and thiosemicarbazide, but not tert-butyl carbazate. The substituent on the pyrrolidine nitrogen can be alkoxycarbonyl, sulfonyl, or an N-alkyl-2-acylpyrrole group. Siloxy substitution at C1 of the alpha-ketoester side chain is also tolerated.
Subject(s)
Cyclopentanes/chemistry , Cyclopentanes/chemical synthesis , Imines/chemistry , Molecular Structure , StereoisomerismABSTRACT
A series of 4'-[(imidazol-1-yl)methyl]biphenylsulfonamides has potent antagonist activity against both angiotensin II AT(1) and endothelin ET(A) receptors. Such dual-acting antagonists could have utility in the treatment of hypertension, heart failure, and other cardiovascular diseases in a broad patient population. Certain compounds in the present series are orally active in a rat model of angiotensin II-mediated hypertension.