ABSTRACT
A focused SAR study was conducted on a series of N1-substituted pyrazolopyrimidinone PDE2 inhibitors to reveal compounds with excellent potency and selectivity. The series was derived from previously identified internal leads and designed to enhance steric interactions with key amino acids in the PDE2 binding pocket. Compound 26 was identified as a lead compound with excellent PDE2 selectivity and good physicochemical properties.
Subject(s)
Cyclic Nucleotide Phosphodiesterases, Type 2/antagonists & inhibitors , Drug Discovery , Phosphodiesterase Inhibitors/pharmacology , Pyrazoles/pharmacology , Pyrimidinones/pharmacology , Crystallography, X-Ray , Cyclic Nucleotide Phosphodiesterases, Type 2/metabolism , Dose-Response Relationship, Drug , Humans , Models, Molecular , Molecular Structure , Phosphodiesterase Inhibitors/chemical synthesis , Phosphodiesterase Inhibitors/chemistry , Pyrazoles/chemical synthesis , Pyrazoles/chemistry , Pyrimidinones/chemical synthesis , Pyrimidinones/chemistry , Structure-Activity RelationshipABSTRACT
Herein, we describe our research efforts to develop unique cores in molecules which function as HCV nonstructural protein 5A (NS5A) inhibitors. In particular, various fused tetracyclic cores were identified which showed genotype and mutant activities comparable to the indole-based tetracyclic core.
Subject(s)
Indoles/pharmacology , Viral Nonstructural Proteins/antagonists & inhibitors , Antiviral Agents/pharmacology , Hepacivirus/drug effectsABSTRACT
Herein we describe our research efforts around the aryl and heteroaryl substitutions at the aminal carbon of the tetracyclic indole-based HCV NS5A inhibitor MK-8742. A series of potent NS5A inhibitors are described, such as compounds 45-47, 54, 56, and 65, which showed improved potency against clinically relevant and resistance associated HCV variants. The improved potency profiles of these compounds demonstrated an SAR that can improve the potency against GT2b, GT1a Y93H, and GT1a L31V altogether, which was unprecedented in our previous efforts in NS5A inhibition.
Subject(s)
Antiviral Agents/pharmacology , Benzofurans/pharmacology , Hepacivirus/drug effects , Imidazoles/pharmacology , Viral Nonstructural Proteins/antagonists & inhibitors , Animals , Antiviral Agents/chemical synthesis , Antiviral Agents/chemistry , Benzofurans/chemical synthesis , Benzofurans/chemistry , Dose-Response Relationship, Drug , Imidazoles/chemical synthesis , Imidazoles/chemistry , Male , Microbial Sensitivity Tests , Molecular Structure , Rats , Rats, Sprague-Dawley , Structure-Activity RelationshipABSTRACT
A matched and mixed capping SAR study was conducted on the tetracyclic indole class of HCV NS5A inhibitors to examine the influence of modifications of this region on the overall HCV virologic resistance profiles.
Subject(s)
Antiviral Agents/chemistry , Hepacivirus/metabolism , Indoles/chemistry , Viral Nonstructural Proteins/antagonists & inhibitors , Animals , Antiviral Agents/metabolism , Antiviral Agents/pharmacology , Area Under Curve , Genotype , Half-Life , Hepacivirus/drug effects , Hepacivirus/genetics , Indoles/metabolism , Indoles/pharmacology , ROC Curve , Rats , Structure-Activity Relationship , Viral Nonstructural Proteins/metabolismABSTRACT
HCV NS5A inhibitors have demonstrated impressive in vitro potency profiles in HCV replicon assays and robust HCV RNA titer reduction in the clinic making them attractive components for inclusion in an all oral fixed dose combination regimen for the treatment of HCV infection. Herein we describe our continued research efforts around the alkyl "Z group" modification of the tetracyclic indole-based NS5A inhibitor MK-8742, which led to the discovery of a series of potent NS5A inhibitors. Compounds 10 and 19 are of particular interests since they are as potent as our previous leads and have much improved rat pharmacokinetic profiles.
Subject(s)
Antiviral Agents/pharmacology , Benzofurans/pharmacology , Hepacivirus/drug effects , Imidazoles/pharmacology , Viral Nonstructural Proteins/antagonists & inhibitors , Animals , Antiviral Agents/chemical synthesis , Antiviral Agents/chemistry , Benzofurans/chemical synthesis , Benzofurans/chemistry , Dose-Response Relationship, Drug , Hepatitis C/drug therapy , Imidazoles/chemical synthesis , Imidazoles/chemistry , Male , Microbial Sensitivity Tests , Molecular Structure , Rats , Rats, Sprague-Dawley , Structure-Activity Relationship , Virus Replication/drug effectsABSTRACT
HCV NS5A inhibitors have demonstrated impressive in vitro virologic profiles in HCV replicon assays and robust HCV RNA titer reduction in the clinic making them attractive components for inclusion in an all oral fixed-dose combination (FDC) regimen for the treatment of HCV infection. Merck's effort in this area identified MK-4882 and MK-8325 as early development leads. Herein, we describe the discovery of potent macrocyclic NS5A inhibitors bearing the MK-8325 or MK-4882 core structure.
Subject(s)
Antiviral Agents/pharmacology , Drug Discovery , Hepacivirus/drug effects , Heterocyclic Compounds, 4 or More Rings/pharmacology , Macrocyclic Compounds/pharmacology , Viral Nonstructural Proteins/antagonists & inhibitors , Antiviral Agents/chemical synthesis , Antiviral Agents/chemistry , Dose-Response Relationship, Drug , Hepatitis C/drug therapy , Heterocyclic Compounds, 4 or More Rings/chemical synthesis , Heterocyclic Compounds, 4 or More Rings/chemistry , Macrocyclic Compounds/chemical synthesis , Macrocyclic Compounds/chemistry , Microbial Sensitivity Tests , Molecular Structure , Structure-Activity Relationship , Virus Replication/drug effectsABSTRACT
As part of an ongoing effort in NS5A inhibition at Merck we now describe our efforts for introducing substitution around the tetracyclic indole core of MK-8742. Fluoro substitution on the core combined with the fluoro substitutions on the proline ring improved the potency against GT1a Y93H significantly. However, no improvement on GT2b potency was achieved. Limiting the fluoro substitution to C-1 of the tetracyclic indole core had a positive impact on the potency against the resistance associated variants, such as GT1a Y93H and GT2b, and the PK profile as well. Compounds, such as 62, with reduced potency shifts between wild type GT1a to GT2b, GT1a Y93H, and GT1a L31V were identified.
Subject(s)
Antiviral Agents/pharmacology , Benzofurans/pharmacology , Imidazoles/pharmacology , Indoles/pharmacology , Viral Nonstructural Proteins/antagonists & inhibitors , Antiviral Agents/chemistry , Antiviral Agents/pharmacokinetics , Benzofurans/chemistry , Benzofurans/pharmacokinetics , Imidazoles/chemistry , Imidazoles/pharmacokinetics , Indoles/chemistry , Indoles/pharmacokinetics , Structure-Activity RelationshipABSTRACT
We describe the impact of proline modifications, in our tetracyclic-indole based series of nonstructural protein 5A (NS5A) inhibitors, to their replicon profiles. This work identified NS5A inhibitors with an improved and flattened resistance profiles.
Subject(s)
Antiviral Agents/pharmacology , Benzofurans/pharmacology , Imidazoles/pharmacology , Indoles/chemistry , Proline/chemistry , Viral Nonstructural Proteins/antagonists & inhibitors , Antiviral Agents/chemistry , Benzofurans/chemistry , Imidazoles/chemistry , Structure-Activity RelationshipABSTRACT
HCV NS5A inhibitors have demonstrated impressive in vitro potency profiles in HCV replicon assays and robust HCV RNA titer reduction in the clinic making them attractive components for inclusion in an all oral fixed dose combination regimen for the treatment of HCV infection. Herein, we describe research efforts that led to the discovery of a series of fused tricyclic core containing HCV NS5A inhibitors such as 24, 39, 40, 43, and 44 which have pan-genotype activity and are orally bioavailable in the rat.
Subject(s)
Antiviral Agents/pharmacology , Drug Discovery , Hepacivirus/drug effects , Hepatitis C/drug therapy , Viral Nonstructural Proteins/antagonists & inhibitors , Antiviral Agents/chemical synthesis , Antiviral Agents/chemistry , Dose-Response Relationship, Drug , Genotype , Microbial Sensitivity Tests , Molecular Structure , Structure-Activity Relationship , Viral Nonstructural Proteins/genetics , Virus Replication/drug effectsABSTRACT
HCV NS5A inhibitors have shown impressive in vitro potency profiles in HCV replicon assays thus making them attractive components for inclusion in an all oral fixed dose combination treatment regimen. Herein we describe the research efforts that led to the discovery of silyl proline containing HCV NS5A inhibitors such as 7e and 8a with pan-genotype activity profile and acceptable pharmacokinetic properties.
Subject(s)
Antiviral Agents/chemistry , Antiviral Agents/pharmacology , Drug Discovery , Hepacivirus/drug effects , Hepacivirus/genetics , Proline/analogs & derivatives , Silanes/chemistry , Viral Nonstructural Proteins/antagonists & inhibitors , Antiviral Agents/chemical synthesis , Dose-Response Relationship, Drug , Genotype , Microbial Sensitivity Tests , Molecular Structure , Silanes/pharmacology , Structure-Activity Relationship , Viral Nonstructural Proteins/genetics , Virus Replication/drug effectsABSTRACT
The ribonucleotide reductase (RNR) enzyme is a heteromer of RRM1 and RRM2 subunits. The active enzyme catalyzes de novo reduction of ribonucleotides to generate deoxyribonucleotides (dNTPs), which are required for DNA replication and DNA repair processes. Complexity in the generation of physiologically relevant, active RRM1/RRM2 heterodimers was perceived as limiting to the identification of selective RRM1 inhibitors by high-throughput screening of compound libraries and led us to seek alternative methods to identify lead series. In short, we found that gemcitabine, as its diphosphate metabolite, represents one of the few described active site inhibitors of RRM1. We herein describe the identification of novel 5'-amino gemcitabine analogs as potent RRM1 inhibitors through in-cell phenotypic screening.
Subject(s)
Deoxycytidine/analogs & derivatives , Tumor Suppressor Proteins/antagonists & inhibitors , Cell Line, Tumor , Deoxycytidine/chemistry , Deoxycytidine/pharmacology , Dose-Response Relationship, Drug , High-Throughput Screening Assays , Humans , Magnetic Resonance Spectroscopy , Molecular Structure , Ribonucleoside Diphosphate Reductase , Structure-Activity Relationship , GemcitabineABSTRACT
The synthesis and hit-to-lead SAR development from a pyrazolo[1,5-a]pyrimidine-derived hit 5 to the identification of a series of potent, pan-Pim inhibitors such as 11j are described.
Subject(s)
Protein Kinase Inhibitors/chemistry , Protein Kinase Inhibitors/pharmacology , Proto-Oncogene Proteins c-pim-1/antagonists & inhibitors , Pyrimidines/chemistry , Pyrimidines/pharmacology , Humans , Protein Binding , Protein Kinase Inhibitors/chemical synthesis , Proto-Oncogene Proteins c-pim-1/chemistry , Pyrazoles/chemical synthesis , Pyrazoles/chemistry , Pyrazoles/pharmacology , Pyrimidines/chemical synthesis , Structure-Activity RelationshipABSTRACT
Previous efforts by our group have established pyrazolo[1,5-a]pyrimidine as a viable core for the development of potent and selective CDK inhibitors. As part of an effort to utilize the pyrazolo[1,5-a]pyrimidine core as a template for the design and synthesis of potent and selective kinase inhibitors, we focused on a key regulator in the cell cycle progression, CHK1. Continued SAR development of the pyrazolo[1,5-a]pyrimidine core at the C5 and C6 positions, in conjunction with previously disclosed SAR at the C3 and C7 positions, led to the discovery of potent and selective CHK1 inhibitors.
Subject(s)
Protein Kinase Inhibitors/chemistry , Protein Kinases/chemistry , Pyrazoles/chemistry , Pyrimidines/chemistry , Binding Sites , Catalytic Domain , Checkpoint Kinase 1 , Crystallography, X-Ray , Cyclin-Dependent Kinase 2/antagonists & inhibitors , Cyclin-Dependent Kinase 2/metabolism , Drug Evaluation, Preclinical , Protein Kinase Inhibitors/chemical synthesis , Protein Kinase Inhibitors/pharmacology , Protein Kinases/metabolism , Pyrazoles/chemical synthesis , Pyrazoles/pharmacology , Pyrimidines/chemical synthesis , Pyrimidines/pharmacology , Structure-Activity RelationshipABSTRACT
The synthesis and hit-to-lead SAR development of a pyrazolo[1,5-a]pyrimidine hit 4 is described leading to a series of potent, selective CHK1 inhibitors such as compound 17r. In the Letter, the further utility of the pyrazolo[1,5-a]pyrimidine template for the development of potent, selective kinase inhibitors is detailed.
Subject(s)
Protein Kinase Inhibitors/chemistry , Protein Kinases/chemistry , Pyrazoles/chemistry , Pyrimidines/chemistry , Binding Sites , Catalytic Domain , Checkpoint Kinase 1 , Crystallography, X-Ray , Cyclin-Dependent Kinase 2/antagonists & inhibitors , Cyclin-Dependent Kinase 2/metabolism , Drug Evaluation, Preclinical , Protein Kinase Inhibitors/chemical synthesis , Protein Kinase Inhibitors/pharmacology , Protein Kinases/metabolism , Pyrazoles/chemical synthesis , Pyrazoles/pharmacology , Pyrimidines/chemical synthesis , Pyrimidines/pharmacology , Structure-Activity RelationshipABSTRACT
A series of potent and orally bioavailable 3,4-diaminocyclobutenediones with various fluoroalkyl groups as alpha side chain were prepared and found to show significant improvements in the binding affinities towards both CXCR2 and CXCR1 receptors.
Subject(s)
Cyclobutanes/chemical synthesis , Receptors, Interleukin-8A/antagonists & inhibitors , Receptors, Interleukin-8B/antagonists & inhibitors , Administration, Oral , Animals , Binding Sites , Cyclobutanes/administration & dosage , Cyclobutanes/metabolism , Protein Binding , Rats , Receptors, Interleukin-8A/metabolism , Receptors, Interleukin-8B/metabolismABSTRACT
A series of potent and orally bioavailable 3,4-diaminocyclobutenediones with various amide modifications and substitution on the left side phenyl ring were prepared and found to show significant inhibitory activities towards both CXCR2 and CXCR1 receptors.
Subject(s)
Amides/chemistry , Cyclobutanes/chemical synthesis , Diamines/chemical synthesis , Phenol/chemistry , Receptors, Interleukin-8A/antagonists & inhibitors , Receptors, Interleukin-8B/antagonists & inhibitors , Administration, Oral , Animals , Area Under Curve , Chemistry, Pharmaceutical/methods , Cyclobutanes/pharmacology , Diamines/pharmacology , Drug Design , Humans , Inflammation , Kinetics , Models, Chemical , Rats , Structure-Activity RelationshipABSTRACT
Comprehensive SAR studies were undertaken in the 3,4-diaminocyclobut-3-ene-1,2-dione class of CXCR2/CXCR1 receptor antagonists to explore the role of the heterocycle on chemokine receptor binding affinities, functional activity, as well as oral exposure in rat. The nature of the heterocycle as well as the requisite substitution pattern around the heterocycle was shown to have a dramatic effect on the overall biological profile of this class of compounds. The furyl class, particularly the 4-halo adducts, was found to possess superior binding affinities for both the CXCR2 and CXCR1 receptors, functional activity, as well as oral exposure in rat versus other heterocyclic derivatives.
Subject(s)
Cyclobutanes/chemistry , Cyclobutanes/pharmacology , Diamines/chemistry , Diamines/pharmacology , Receptors, Interleukin-8A/antagonists & inhibitors , Receptors, Interleukin-8B/antagonists & inhibitors , Animals , Cell Line , Cyclobutanes/chemical synthesis , Diamines/chemical synthesis , Heterocyclic Compounds/chemical synthesis , Heterocyclic Compounds/chemistry , Heterocyclic Compounds/pharmacology , Mice , Stereoisomerism , Structure-Activity RelationshipABSTRACT
Herein we describe the development of a series of pyrazolopyrimidinone phosphodiesterase 2A (PDE2) inhibitors using structure-guided lead identification and design. The series was derived from informed chemotype replacement based on previously identified internal leads. The initially designed compound 3, while potent on PDE2, displayed unsatisfactory selectivity against the other PDE2 isoforms. Compound 3 was subsequently optimized for improved PDE2 activity and isoform selectivity. Insights into the origins of PDE2 selectivity are described and verified using cocrystallography. An optimized lead, 4, demonstrated improved performance in both a rodent and a nonhuman primate cognition model.
ABSTRACT
We describe the research that led to the discovery of compound 40 (ruzasvir, MK-8408), a pan-genotypic HCV nonstructural protein 5A (NS5A) inhibitor with a "flat" GT1 mutant profile. This NS5A inhibitor contains a unique tetracyclic indole core while maintaining the imidazole-proline-valine Moc motifs of our previous NS5A inhibitors. Compound 40 is currently in early clinical trials and is under evaluation as part of an all-oral DAA regimen for the treatment of chronic HCV infection.
Subject(s)
Antiviral Agents/chemistry , Antiviral Agents/pharmacology , Hepacivirus/drug effects , Heterocyclic Compounds, 4 or More Rings/chemistry , Heterocyclic Compounds, 4 or More Rings/pharmacology , Polymorphism, Genetic , Pyrrolidines/chemistry , Pyrrolidines/pharmacology , Thiazoles/chemistry , Thiazoles/pharmacology , Viral Nonstructural Proteins/antagonists & inhibitors , Animals , Antiviral Agents/pharmacokinetics , Cell Line , Dogs , Haplorhini , Hepacivirus/genetics , Heterocyclic Compounds, 4 or More Rings/pharmacokinetics , Humans , Pyrrolidines/pharmacokinetics , Rats , Structure-Activity Relationship , Thiazoles/pharmacokineticsABSTRACT
Using the HIV-1 protease binding mode of MK-8718 and PL-100 as inspiration, a novel aspartate binding bicyclic piperazine sulfonamide core was designed and synthesized. The resulting HIV-1 protease inhibitor containing this core showed an 60-fold increase in enzyme binding affinity and a 10-fold increase in antiviral activity relative to MK-8718.