ABSTRACT
The use of ß-lactam (BL) and ß-lactamase inhibitor combination to overcome BL antibiotic resistance has been validated through clinically approved drug products. However, unmet medical needs still exist for the treatment of infections caused by Gram-negative (GN) bacteria expressing metallo-ß-lactamases. Previously, we reported our effort to discover pan inhibitors of three main families in this class: IMP, VIM, and NDM. Herein, we describe our work to improve the GN coverage spectrum in combination with imipenem and relebactam. This was achieved through structure- and property-based optimization to tackle the GN cell penetration and efflux challenges. A significant discovery was made that inhibition of both VIM alleles, VIM-1 and VIM-2, is essential for broad GN coverage, especially against VIM-producing P. aeruginosa. In addition, pharmacokinetics and nonclinical safety profiles were investigated for select compounds. Key findings from this drug discovery campaign laid the foundation for further lead optimization toward identification of preclinical candidates.
Subject(s)
Anti-Bacterial Agents , beta-Lactamase Inhibitors , Humans , beta-Lactamase Inhibitors/pharmacology , beta-Lactamase Inhibitors/therapeutic use , beta-Lactamase Inhibitors/chemistry , Anti-Bacterial Agents/chemistry , Imipenem/pharmacology , beta-Lactamases , Gram-Negative Bacteria , Microbial Sensitivity TestsABSTRACT
DNA-encoded library (DEL) technology holds exciting potential for discovering novel therapeutic macrocyclic peptides (MPs). Herein, we describe the development of a DEL-compatible peptide macrocyclization method that proceeds via intramolecular click-condensation between 3-(2-cyano-4-pyridyl)-l-alanine (Cpa) and an N-terminal cysteine. Cyclization takes place spontaneously in a buffered aqueous solution and affords the cyclized products in excellent yields. The reaction exhibits a broad substrate scope and can be employed to generate MPs of variable ring size and amino acid composition.
Subject(s)
Nitriles , Peptides , Peptides/chemistry , Sulfhydryl Compounds/chemistry , Cysteine/chemistry , DNAABSTRACT
Inhibition of leucine-rich repeat kinase 2 (LRRK2) kinase activity represents a genetically supported, chemically tractable, and potentially disease-modifying mechanism to treat Parkinson's disease. Herein, we describe the optimization of a novel series of potent, selective, central nervous system (CNS)-penetrant 1-heteroaryl-1H-indazole type I (ATP competitive) LRRK2 inhibitors. Type I ATP-competitive kinase physicochemical properties were integrated with CNS drug-like properties through a combination of structure-based drug design and parallel medicinal chemistry enabled by sp3-sp2 cross-coupling technologies. This resulted in the discovery of a unique sp3-rich spirocarbonitrile motif that imparted extraordinary potency, pharmacokinetics, and favorable CNS drug-like properties. The lead compound, 25, demonstrated exceptional on-target potency in human peripheral blood mononuclear cells, excellent off-target kinase selectivity, and good brain exposure in rat, culminating in a low projected human dose and a pre-clinical safety profile that warranted advancement toward pre-clinical candidate enabling studies.
Subject(s)
Parkinson Disease , Rats , Humans , Animals , Leucine-Rich Repeat Serine-Threonine Protein Kinase-2 , Parkinson Disease/drug therapy , Indazoles/pharmacology , Indazoles/therapeutic use , Leukocytes, Mononuclear/metabolism , Protein Kinase Inhibitors/pharmacology , Protein Kinase Inhibitors/therapeutic use , Protein Kinase Inhibitors/chemistry , Brain/metabolism , Adenosine TriphosphateABSTRACT
The discovery of potent, kinome selective, brain penetrant LRRK2 inhibitors is the focus of extensive research seeking new, disease-modifying treatments for Parkinson's disease (PD). Herein, we describe the discovery and evolution of a picolinamide-derived lead series. Our initial optimization efforts aimed at improving the potency and CLK2 off-target selectivity of compound 1 by modifying the heteroaryl C-H hinge and linker regions. This resulted in compound 12 which advanced deep into our research operating plan (ROP) before heteroaryl aniline metabolite 14 was characterized as Ames mutagenic, halting its progression. Strategic modifications to our ROP were made to enable early de-risking of putative aniline metabolites or hydrolysis products for mutagenicity in Ames. This led to the discovery of 3,5-diaminopyridine 15 and 4,6-diaminopyrimidine 16 as low risk for mutagenicity (defined by a 3-strain Ames negative result). Analysis of key matched molecular pairs 17 and 18 led to the prioritization of the 3,5-diaminopyridine sub-series for further optimization due to enhanced rodent brain penetration. These efforts culminated in the discovery of ethyl trifluoromethyl pyrazole 23 with excellent LRRK2 potency and expanded selectivity versus off-target CLK2.
ABSTRACT
A robust palladium-catalyzed hydroxycarbonylation of aryl halides on DNA has been developed. Instead of Mo(CO)6 as a source of carbon monoxide as previously described in the literature, chloroform was used as a surrogate in this report for the purpose of avoiding to use a large excess of molybdenum reagent which is not totally soluble in aqueous reaction mixtures.
Subject(s)
Carbon Monoxide/chemistry , Chloroform/chemistry , DNA/chemistry , Molecular StructureABSTRACT
Leucine-rich repeat kinase 2 (LRRK2) is a large, multidomain protein which contains a kinase domain and GTPase domain among other regions. Individuals possessing gain of function mutations in the kinase domain such as the most prevalent G2019S mutation have been associated with an increased risk for the development of Parkinson's disease (PD). Given this genetic validation for inhibition of LRRK2 kinase activity as a potential means of affecting disease progression, our team set out to develop LRRK2 inhibitors to test this hypothesis. A high throughput screen of our compound collection afforded a number of promising indazole leads which were truncated in order to identify a minimum pharmacophore. Further optimization of these indazoles led to the development of MLi-2 (1): a potent, highly selective, orally available, brain-penetrant inhibitor of LRRK2.
Subject(s)
Enzyme Inhibitors/chemistry , Enzyme Inhibitors/pharmacology , Indazoles/chemistry , Indazoles/pharmacology , Leucine-Rich Repeat Serine-Threonine Protein Kinase-2/antagonists & inhibitors , Animals , Brain/metabolism , Enzyme Inhibitors/administration & dosage , Enzyme Inhibitors/pharmacokinetics , Humans , Indazoles/administration & dosage , Indazoles/pharmacokinetics , Leucine-Rich Repeat Serine-Threonine Protein Kinase-2/metabolism , Male , Molecular Docking Simulation , Parkinson Disease/drug therapy , Parkinson Disease/enzymology , Rats , Rats, WistarABSTRACT
Verubecestat 3 (MK-8931), a diaryl amide-substituted 3-imino-1,2,4-thiadiazinane 1,1-dioxide derivative, is a high-affinity ß-site amyloid precursor protein cleaving enzyme 1 (BACE1) inhibitor currently undergoing Phase 3 clinical evaluation for the treatment of mild to moderate and prodromal Alzheimer's disease. Although not selective over the closely related aspartyl protease BACE2, verubecestat has high selectivity for BACE1 over other key aspartyl proteases, notably cathepsin D, and profoundly lowers CSF and brain Aß levels in rats and nonhuman primates and CSF Aß levels in humans. In this annotation, we describe the discovery of 3, including design, validation, and selected SAR around the novel iminothiadiazinane dioxide core as well as aspects of its preclinical and Phase 1 clinical characterization.
Subject(s)
Alzheimer Disease/drug therapy , Amyloid beta-Protein Precursor/antagonists & inhibitors , Cyclic S-Oxides/pharmacology , Drug Discovery , Thiadiazines/pharmacology , Alzheimer Disease/metabolism , Amyloid beta-Protein Precursor/metabolism , Animals , Cyclic S-Oxides/chemical synthesis , Cyclic S-Oxides/chemistry , Dogs , Dose-Response Relationship, Drug , Humans , Macaca fascicularis , Models, Molecular , Molecular Structure , Rats , Rats, Sprague-Dawley , Structure-Activity Relationship , Thiadiazines/chemical synthesis , Thiadiazines/chemistryABSTRACT
ß-Amyloid (Aß) peptides are thought to be critically involved in the etiology of Alzheimer's disease (AD). The aspartyl protease ß-site amyloid precursor protein cleaving enzyme 1 (BACE1) is required for the production of Aß, and BACE1 inhibition is thus an attractive target for the treatment of AD. We show that verubecestat (MK-8931) is a potent, selective, structurally unique BACE1 inhibitor that reduced plasma, cerebrospinal fluid (CSF), and brain concentrations of Aß40, Aß42, and sAPPß (a direct product of BACE1 enzymatic activity) after acute and chronic administration to rats and monkeys. Chronic treatment of rats and monkeys with verubecestat achieved exposures >40-fold higher than those being tested in clinical trials in AD patients yet did not elicit many of the adverse effects previously attributed to BACE inhibition, such as reduced nerve myelination, neurodegeneration, altered glucose homeostasis, or hepatotoxicity. Fur hypopigmentation was observed in rabbits and mice but not in monkeys. Single and multiple doses were generally well tolerated and produced reductions in Aß40, Aß42, and sAPPß in the CSF of both healthy human subjects and AD patients. The human data were fit to an amyloid pathway model that provided insight into the Aß pools affected by BACE1 inhibition and guided the choice of doses for subsequent clinical trials.
Subject(s)
Alzheimer Disease/metabolism , Amyloid Precursor Protein Secretases/antagonists & inhibitors , Amyloid beta-Peptides/chemistry , Aspartic Acid Endopeptidases/antagonists & inhibitors , Central Nervous System/metabolism , Cyclic S-Oxides/pharmacology , Thiadiazines/pharmacology , Administration, Oral , Amyloid Precursor Protein Secretases/metabolism , Animals , Aspartic Acid Endopeptidases/metabolism , Brain/metabolism , Catalytic Domain , Crystallography, X-Ray , Drug Design , Female , Glucose/metabolism , Macaca fascicularis , Magnetic Resonance Spectroscopy , Mice , Myelin Sheath/chemistry , Peptides/chemistry , Rabbits , RatsABSTRACT
Mutations in the leucine-rich repeat kinase 2 (LRRK2) gene are the most common genetic cause of familial and sporadic Parkinson's disease (PD). That the most prevalent mutation, G2019S, leads to increased kinase activity has led to a concerted effort to identify LRRK2 kinase inhibitors as a potential disease-modifying therapy for PD. An internal medicinal chemistry effort identified several potent and highly selective compounds with favorable drug-like properties. Here, we characterize the pharmacological properties of cis-2,6-dimethyl-4-(6-(5-(1-methylcyclopropoxy)-1H-indazol-3-yl)pyrimidin-4-yl)morpholine (MLi-2), a structurally novel, highly potent, and selective LRRK2 kinase inhibitor with central nervous system activity. MLi-2 exhibits exceptional potency in a purified LRRK2 kinase assay in vitro (IC50 = 0.76 nM), a cellular assay monitoring dephosphorylation of LRRK2 pSer935 LRRK2 (IC50 = 1.4 nM), and a radioligand competition binding assay (IC50 = 3.4 nM). MLi-2 has greater than 295-fold selectivity for over 300 kinases in addition to a diverse panel of receptors and ion channels. Acute oral and subchronic dosing in MLi-2 mice resulted in dose-dependent central and peripheral target inhibition over a 24-hour period as measured by dephosphorylation of pSer935 LRRK2. Treatment of MitoPark mice with MLi-2 was well tolerated over a 15-week period at brain and plasma exposures >100× the in vivo plasma IC50 for LRRK2 kinase inhibition as measured by pSer935 dephosphorylation. Morphologic changes in the lung, consistent with enlarged type II pneumocytes, were observed in MLi-2-treated MitoPark mice. These data demonstrate the suitability of MLi-2 as a compound to explore LRRK2 biology in cellular and animal models.
Subject(s)
Antiparkinson Agents/adverse effects , Antiparkinson Agents/therapeutic use , Indazoles/pharmacology , Protein Kinase Inhibitors/adverse effects , Protein Kinase Inhibitors/therapeutic use , Protein Serine-Threonine Kinases/antagonists & inhibitors , Pyrimidines/pharmacology , Alveolar Epithelial Cells/drug effects , Alveolar Epithelial Cells/pathology , Animals , Behavior, Animal/drug effects , Binding, Competitive , Brain/metabolism , Brain Chemistry/drug effects , Cell Line , Cerebral Cortex/drug effects , Cerebral Cortex/metabolism , Dose-Response Relationship, Drug , Humans , Leucine-Rich Repeat Serine-Threonine Protein Kinase-2 , Lung/pathology , Male , Mice , Mice, Inbred C57BL , Mutation/genetics , Parkinson Disease/drug therapy , Parkinson Disease/pathology , Parkinson Disease/psychology , Phosphorylation , Protein Serine-Threonine Kinases/genetics , Protein Serine-Threonine Kinases/metabolismABSTRACT
Overactivity of the hypothalamic-pituitary-adrenal (HPA) axis has been linked to affective disorders such as anxiety and depression. Dampening HPA activity has, therefore, been considered as a possible means of treating affective disorders. Given the important role of vasopressin in modulating the HPA axis, one strategy has focused on inhibiting activity of the vasopressin 1b (V1b) receptor. In animals, V1b receptor antagonists reduce plasma stress hormone levels and have been shown to have an anxiolytic-like effect. Recently, V1B-30N was identified as a highly potent V1b receptor antagonist with selectivity over other vasopressin receptors, which is evaluated here in rodent models of anxiety-like and depression-like behaviors. V1B-30N (1-30mg/kg, IP) dose-dependently reduced separation-induced vocalizations in rat pups without producing any sedative effects in the animals. Similarly, V1B-30N (3-30mg/kg, IP) dose-dependently reduced separation-induced vocalizations in guinea pig pups. In a conflict assay, conditioned lick suppression, V1B-30N (3-30mg/kg, IP) increased punished licking. To assess antidepressive-like properties, V1B-30N (1-30mg/kg) was tested in the mouse and rat forced-swim tests but was found to be inactive. These results are consistent with previous findings with other V1b antagonists, which suggest that acute pharmacological antagonism of the V1b receptor has anxiolytic-like but not antidepressant-like properties.
Subject(s)
Anti-Anxiety Agents/pharmacology , Antidepressive Agents/pharmacology , Antidiuretic Hormone Receptor Antagonists/pharmacology , Anxiety/drug therapy , Behavior, Animal/drug effects , Depression/drug therapy , Receptors, Vasopressin/metabolism , Animals , Anti-Anxiety Agents/therapeutic use , Antidepressive Agents/therapeutic use , Conditioning, Psychological/drug effects , Female , Guinea Pigs , Male , Mice , Rats , Swimming , Vocalization, Animal/drug effectsABSTRACT
Inhibition of BACE1 to prevent brain Aß peptide formation is a potential disease-modifying approach to the treatment of Alzheimer's disease. Despite over a decade of drug discovery efforts, the identification of brain-penetrant BACE1 inhibitors that substantially lower CNS Aß levels following systemic administration remains challenging. In this report we describe structure-based optimization of a series of brain-penetrant BACE1 inhibitors derived from an iminopyrimidinone scaffold. Application of structure-based design in tandem with control of physicochemical properties culminated in the discovery of compound 16, which potently reduced cortex and CSF Aß40 levels when administered orally to rats.
ABSTRACT
The syntheses and SAR investigations of novel CB(1) receptor antagonists based on a 1,2-diaryl piperidine core have been described. Optimization of this core afforded a compound with robust in vivo potency by reducing food intake in a mouse DIO model.
Subject(s)
Piperidines/chemistry , Piperidines/pharmacology , Receptor, Cannabinoid, CB1/antagonists & inhibitors , Animals , Diet/adverse effects , Eating/drug effects , Eating/physiology , Mice , Mice, Obese , Obesity/etiology , Obesity/metabolism , Piperidines/administration & dosage , Protein Binding/physiology , Receptor, Cannabinoid, CB1/metabolism , Structure-Activity RelationshipABSTRACT
Vasopressin 1b (V1b) antagonists have been postulated as possible treatments for depression and anxiety. A novel series of potent and selective V1b antagonists has been identified starting from an in-house screen hit. The incorporation of a sulfonamide linker between a tetrahydroisoquinoline core and amino piperidine lead to the identification of a V1b antagonist with similar affinity for human and rat receptors. Further optimization of the right hand portion afforded potent V1b antagonists that possessed moderate to high selectivity over other receptors.
Subject(s)
Antidiuretic Agents/chemistry , Antidiuretic Hormone Receptor Antagonists , Quinolines/chemistry , Sulfonamides/chemistry , Animals , Antidiuretic Agents/chemical synthesis , Antidiuretic Agents/pharmacology , Humans , Quinolines/chemical synthesis , Quinolines/pharmacology , Rats , Receptors, Oxytocin/antagonists & inhibitors , Receptors, Oxytocin/metabolism , Receptors, Vasopressin/metabolism , Structure-Activity Relationship , Sulfonamides/chemical synthesis , Sulfonamides/pharmacologyABSTRACT
The first total synthesis of the potent antitumor antibiotic (-)-tetrazomine has been accomplished. A new method for the formation of the allylic amine precursor to an azomethine ylide has been developed and exploited in an efficient [1,3]-dipolar cycloaddition to afford the key tetracyclic intermediate used in the synthesis of (-)-tetrazomine. Several analogues of tetrazomine have been synthesized and tested for antimicrobial and biochemical activity.
Subject(s)
Anti-Bacterial Agents/chemical synthesis , Piperidines/chemical synthesis , Anti-Bacterial Agents/chemistry , Anti-Bacterial Agents/pharmacology , Base Sequence , DNA/drug effects , DNA/metabolism , Klebsiella pneumoniae/drug effects , Microbial Sensitivity Tests , Molecular Sequence Data , Piperidines/chemistry , Piperidines/pharmacology , Staphylococcus aureus/drug effects , Stereoisomerism , Structure-Activity RelationshipABSTRACT
A new method for the formation of the allylic amine precursor to an azomethine ylide 1 has been developed and exploited in an efficient 1,3-dipolar cycloaddition to afford the key tetracyclic intermediate used in the synthesis of (-)-tetrazomine (2). Bn=benzyl.