ABSTRACT
High-conductance calcium-activated potassium (Maxi-K) channels are present in smooth muscle where they regulate tone. Activation of Maxi-K channels causes smooth muscle hyperpolarization and shortening of action-potential duration, which would limit calcium entry through voltage-dependent calcium channels leading to relaxation. Although Maxi-K channels appear to indirectly mediate the relaxant effects of a number of agents, activators that bind directly to the channel with appropriate potency and pharmacological properties useful for proof-of-concept studies are not available. Most agents identified to date display significant polypharmacy that severely compromises interpretation of experimental data. In the present study, a high-throughput, functional, cell-based assay for identifying Maxi-K channel agonists was established and used to screen a large sample collection (>1.6 million compounds). On the basis of potency and selectivity, a family of tetrahydroquinolines was further characterized. Medicinal chemistry efforts afforded identification of compound X, from which its two enantiomers, Y and Z, were resolved. In in vitro assays, Z is more potent than Y as a channel activator. The same profile is observed in tissues where the ability of either agent to relax precontracted smooth muscles, via a potassium channel-dependent mechanism, is demonstrated. These data, taken together, suggest that direct activation of Maxi-K channels represents a mechanism to be explored for the potential treatment of a number of diseases associated with smooth muscle hyperexcitability.
Subject(s)
Large-Conductance Calcium-Activated Potassium Channels/physiology , Muscle, Smooth/physiology , Animals , CHO Cells , Chromatography, Liquid , Cricetinae , Cricetulus , Large-Conductance Calcium-Activated Potassium Channels/agonists , Magnetic Resonance Spectroscopy , Mass Spectrometry , Muscle RelaxationABSTRACT
This manuscript concludes the Structure Activity Relationship (SAR) on the pyridazinone scaffold and identifies a compound with subnanomolar p38α activity and 24h coverage in the rat arthritis efficacy model.
Subject(s)
Mitogen-Activated Protein Kinase 14/antagonists & inhibitors , Protein Kinase Inhibitors/chemical synthesis , Protein Kinase Inhibitors/pharmacology , Pyridazines/chemical synthesis , Pyridazines/pharmacology , Pyridines/chemical synthesis , Pyridines/pharmacology , Animals , Dogs , Dose-Response Relationship, Drug , Haplorhini , Humans , Mitogen-Activated Protein Kinase 14/metabolism , Molecular Structure , Protein Kinase Inhibitors/administration & dosage , Pyridazines/administration & dosage , Pyridines/administration & dosage , Rats , Structure-Activity RelationshipABSTRACT
The development and synthesis of potent p38α MAP kinase inhibitors containing a pyridazinone platform is described. Evolution of the p38α selective pyridopyridazin-6-one series from the p38α/ß dual inhibitor 2H-quinolizin-2-one series will be discussed in full detail.
Subject(s)
Mitogen-Activated Protein Kinase 14/antagonists & inhibitors , Protein Kinase Inhibitors/chemical synthesis , Pyridazines/chemistry , Animals , Binding Sites , Catalytic Domain , Computer Simulation , Mitogen-Activated Protein Kinase 14/metabolism , Protein Kinase Inhibitors/chemistry , Protein Kinase Inhibitors/pharmacokinetics , Protein Structure, Tertiary , Pyridazines/chemical synthesis , Pyridazines/pharmacokinetics , Rats , Structure-Activity RelationshipABSTRACT
The development and synthesis of potent p38alpha MAP kinase inhibitors containing a 2H-quinolizin-2-one platform is described. Evolution of the 2H-quinolizin-2-one series from an early lead to solving off target activity and pharmacokinetic issues is also discussed.
Subject(s)
Anti-Inflammatory Agents/chemical synthesis , Protein Kinase Inhibitors/chemical synthesis , Quinolizines/chemistry , p38 Mitogen-Activated Protein Kinases/antagonists & inhibitors , Animals , Anti-Inflammatory Agents/chemistry , Anti-Inflammatory Agents/pharmacokinetics , Cell Line , Dogs , Haplorhini , Humans , Protein Kinase Inhibitors/chemistry , Protein Kinase Inhibitors/pharmacokinetics , Quinolizines/chemical synthesis , Quinolizines/pharmacokinetics , Rats , Structure-Activity Relationship , Tumor Necrosis Factor-alpha/metabolism , p38 Mitogen-Activated Protein Kinases/metabolismABSTRACT
Synthesis and biological activities of some quinolinone and dihydroquinolinone p38 MAP kinase inhibitors are reported. Modifications to the dihydroquinolinone pharmacophore revealed that dihydroquinolinone may be replaced with a quinolinone pharmacophore and lead to enhanced p38 inhibitory activity. From a study of C-7 substitutions by amino acid side chains, a very potent series of compounds in the p38 enzyme assays was identified. Translation of the in vitro activity into reasonable whole blood activity can be improved in this series of compounds by judicious modification of the physical properties at appropriate regions of the lead.
Subject(s)
Protein Kinase Inhibitors/chemical synthesis , Protein Kinase Inhibitors/pharmacology , Pyridazines/chemistry , Pyrimidines/chemistry , Quinolones/chemical synthesis , Quinolones/pharmacology , p38 Mitogen-Activated Protein Kinases/antagonists & inhibitors , Crystallography, X-Ray , Cyclization , Humans , Molecular Structure , Quinolones/chemistry , p38 Mitogen-Activated Protein Kinases/metabolismABSTRACT
The initial disclosure of tri-substituted imidazole-based drug molecules such as 1 for inhibition of p38 MAP kinase by SmithKline Beecham (SB) sparked an effort in this area at Merck and other pharmaceutical research establishments. Although analogs in this class have shown good inhibitory properties against p38 MAP kinase, their selectivity profile were modest and left much room for improvement. Attempts to discover newer compounds with improved selectivity over the prototypical SB compound 203580 (1), led to the discovery of a new sub-class of p38 inhibitors typified by compound 18 at Merck. Although this benchmark compound was potent, highly selective and orally efficacious it was burdened with compound related adverse effects in dogs that has delayed further development. In 1999, a new class of p38 inhibitors represented by clinical candidate VX-745 (26), was disclosed by Vertex Pharmaceuticals. This compound displayed unprecedented selectivity due to its unique mode of binding to the active site in p38 MAP kinase. Inspired by the exquisite selectivity profile of VX-745 [26] a scaffold re-design was initiated at Merck which resulted in the discovery of the quinazolinone, pyrimido-pyrimidone, pyrido-pyrimidone, quinolinone and naphthyridinone based p38 inhibitors.
Subject(s)
Drug Design , Enzyme Inhibitors/chemical synthesis , Enzyme Inhibitors/pharmacology , p38 Mitogen-Activated Protein Kinases/antagonists & inhibitors , Binding Sites , Imidazoles/chemistry , Imidazoles/pharmacology , Pyridazines/chemistry , Pyridazines/pharmacology , Pyrimidines/chemistry , Pyrimidines/pharmacology , Pyrimidinones/chemical synthesis , Pyrimidinones/pharmacology , Structure-Activity RelationshipABSTRACT
Imidazo[1,2-a]pyridyl N-arylpyridazinones were hybridized from the classic pyridinylimidazoles and the more recent dual hydrogen bond acceptors, resulting in a new structural class of selective p38 MAP kinase inhibitors.
Subject(s)
Enzyme Inhibitors/chemical synthesis , Mitogen-Activated Protein Kinases/antagonists & inhibitors , Pyridazines/chemical synthesis , Animals , Enzyme Inhibitors/chemistry , Enzyme Inhibitors/pharmacology , Mice , Mitogen-Activated Protein Kinases/chemistry , Models, Molecular , Pyridazines/chemistry , Pyridazines/pharmacology , Structure-Activity Relationship , p38 Mitogen-Activated Protein KinasesABSTRACT
Quinolinones and naphthyridinones with C7 N-t-butyl piperidine substituents were found to be potent p38 MAP kinase inhibitors. These compounds significantly suppress TNF-alpha release in both cellular and LPS-stimulated whole blood assays. They also displayed excellent PK profiles across three animal species. Quinolinone at 10 mpk showed comparable oral efficacy to that of dexamethasone at 1 mpk in a murine collagen-induced arthritis model.
Subject(s)
Enzyme Inhibitors/pharmacology , Naphthyridines/chemistry , Piperidines/chemistry , Quinolones/chemistry , p38 Mitogen-Activated Protein Kinases/antagonists & inhibitors , Animals , Arthritis, Experimental , Collagen/chemistry , Dexamethasone/chemistry , Dogs , Haplorhini , Humans , Inhibitory Concentration 50 , Lipopolysaccharides/metabolism , Mice , Models, Chemical , Rats , Time Factors , Tumor Necrosis Factor-alpha/antagonists & inhibitors , Tumor Necrosis Factor-alpha/chemistry , p38 Mitogen-Activated Protein Kinases/metabolismABSTRACT
Development for a class of potent 3,4-dihydropyrido(3,2-d)pyrimidone inhibitors of p38a MAP kinase is described. Modification of N-1 aryl and C-6 arylsulfide in 3,4-dihydropyrido(3,2-d)pyrimidone analogues for the interaction with the hydrophobic pockets in p38 active site is also discussed.
Subject(s)
Enzyme Inhibitors/chemical synthesis , Mitogen-Activated Protein Kinases/antagonists & inhibitors , Pyrimidinones/chemical synthesis , Enzyme Inhibitors/pharmacology , Kinetics , Molecular Structure , Pyrimidinones/pharmacology , Structure-Activity Relationship , p38 Mitogen-Activated Protein KinasesABSTRACT
We have synthesized a series of C7-piperidine- and 4-aminopiperidine-substituted naphthyridinones, quinolinones, and dihydroquinazolinones that are highly potent inhibitors of both p38MAP kinase activity and TNF-alpha release. The 4-aminopentamethylpiperidine naphthyridinone 5, which was designed to block metabolism at major 'hot spots', combined excellent inhibitory potency with good oral bioavailability in the rat.
Subject(s)
Anti-Infective Agents/chemical synthesis , Anti-Infective Agents/pharmacology , Enzyme Inhibitors/chemical synthesis , Enzyme Inhibitors/pharmacology , Mitogen-Activated Protein Kinases/antagonists & inhibitors , Naphthyridines/chemical synthesis , Naphthyridines/pharmacology , Piperidines/chemical synthesis , Piperidines/pharmacology , Quinazolines/chemical synthesis , Quinazolines/pharmacology , Quinolones/chemical synthesis , Quinolones/pharmacology , Tumor Necrosis Factor-alpha/metabolism , Animals , Area Under Curve , Biological Availability , Dogs , Half-Life , Macaca mulatta , Rats , Structure-Activity Relationship , p38 Mitogen-Activated Protein KinasesABSTRACT
A new class of p38 antagonists based on 3,4-dihydropyrido[3,2,-d]pyrimidine scaffold has been developed. These inhibitors exhibit unprecedented selectivity towards p38 over other very closely related kinases. Compounds 25, 33, and 34 were identified as benchmark analogues for follow-up studies. They show good potency for enzyme inhibition and excellent functional activity.
Subject(s)
Enzyme Inhibitors/chemical synthesis , Enzyme Inhibitors/pharmacology , Mitogen-Activated Protein Kinases/antagonists & inhibitors , Pyridines/chemical synthesis , Pyridines/pharmacology , Pyrimidinones/chemical synthesis , Pyrimidinones/pharmacology , Drug Design , Indicators and Reagents , Structure-Activity Relationship , p38 Mitogen-Activated Protein KinasesABSTRACT
The development of potent, orally bioavailable (in rat) and selective dihydroquinazolinone inhibitors of p38alpha MAP kinase is described. These analogues are hybrids of a pyridinylimidazole p38alpha inhibitor reported by Merck Research Laboratories and VX-745. Optimization of the C-5 phenyl and the C-7 piperidinyl substituents led to the identification of 15i which gave excellent suppression of TNF-alpha production in LPS-stimulated whole blood (IC(50)=10nM) and good oral exposure in rats (F=68%, AUCn PO=0.58 microM h).