Discovery of 4,5,6,7-Tetrahydropyrazolo[1.5-a]pyrizine Derivatives as Core Protein Allosteric Modulators (CpAMs) for the Inhibition of Hepatitis B Virus.

Hepatitis B Virus (HBV) core protein allosteric modulators (CpAMs) are an attractive class of potential anti-HBV therapeutic agents. Here we describe the efforts toward the discovery of a series of 4,5,6,7-tetrahydropyrazolo[1,5-]pyrazine (THPP) compounds as HBV CpAMs that effectively inhibit a broad range of nucleos(t)ide-resistant HBV variants. The lead compound demonstrated inhibition of HBV DNA viral load in a HBV AAV mouse model by oral administration.

Discovery of Linvencorvir (RG7907), a Hepatitis B Virus Core Protein Allosteric Modulator, for the Treatment of Chronic HBV Infection.

Described herein is the first-time disclosure of Linvencorvir (RG7907), a clinical compound and a hepatitis B virus (HBV) core protein allosteric modulator, for the treatment of chronic HBV infection. Built upon the core structure of hetero aryl dihydropyrimidine, RG7907 was rationally designed by combining all the drug-like features of low CYP3A4 induction, potent anti-HBV activity, high metabolic stability, low hERG liability, and favorable animal pharmacokinetic (PK) profiles. In particular, the chemistry strategy to mitigate CYP3A4 induction through introducing a large, rigid, and polar substituent at the position that has less interaction with the therapeutic biological target (HBV core proteins herein) is of general interest to the medicinal chemistry community.

Translation Potential and Challenges of In Vitro and Murine Models in Cancer Clinic.

As one of the leading causes of death from disease, cancer continues to pose a serious threat to human health globally. Despite the development of novel therapeutic regimens and drugs, the long-term survival of cancer patients is still very low, especially for those whose diagnosis is not caught early enough. Meanwhile, our understanding of tumorigenesis is still limited.

Discovery of Novel cccDNA Reducers toward the Cure of Hepatitis B Virus Infection.

Chronic hepatitis B virus (HBV) infection is a worldwide disease that causes thousands of deaths per year. Currently, there is no therapeutic that can completely cure already infected HBV patients due to the inability of humans to eliminate covalently closed circular DNA (cccDNA), which serves as the template to (re)initiate an infection even after prolonged viral suppression. Through phenotypic screening, we discovered xanthone series hits as novel HBV cccDNA reducers, and subsequent structure optimization led to the identification of a lead compound with improved antiviral activity and pharmacokinetic profiles.

Small molecule approaches to treat autoimmune and inflammatory diseases (Part III): Targeting cytokines and cytokine receptor complexes.

Chronic and dysregulated cytokine signaling plays an important role in the pathogenic development of many autoimmune and inflammatory diseases. Despite intrinsic challenges in the disruption of interactions between cytokines and cytokine receptors, many first-in-class small-molecule inhibitors have been discovered over the past few years. The third part of the digest series presents recent progress in identifying such inhibitors and highlights the application of novel research tools in the fields of structural biology, computational analysis, screening methods, biophysical/biochemical assays and medicinal chemistry strategy.

Small molecule approaches to treat autoimmune and inflammatory diseases (Part I): Kinase inhibitors.

Autoimmune and inflammatory diseases place a huge burden on the healthcare system. Small molecule (SM) therapeutics provide much needed complementary treatment options for these diseases. This digest series highlights the latest progress in the discovery and development of safe and efficacious SMs to treat autoimmune and inflammatory diseases with each part representing a class of SMs, namely: 1) protein kinases; 2) nucleic acid-sensing pathways; and 3) soluble ligands and receptors on cell surfaces.

Intramolecular N-Me and N-H aminoetherification for the synthesis of -unprotected 3-amino-O-heterocycles.

A mild Rh-catalyzed method for synthesis of cyclic unprotected N-Me and N-H 2,3-aminoethers using an olefin aziridination-aziridine ring-opening domino reaction has been developed. The method is readily applicable to the stereocontrolled synthesis of a variety of 2,3-disubstituted aminoether O-heterocyclic scaffolds, including tetrahydrofurans, tetrahydropyrans and chromanes.

Phase Separation of Disease-Associated SHP2 Mutants Underlies MAPK Hyperactivation.

The non-receptor protein tyrosine phosphatase (PTP) SHP2, encoded by PTPN11, plays an essential role in RAS-mitogen-activated protein kinase (MAPK) signaling during normal development. It has been perplexing as to why both enzymatically activating and inactivating mutations in PTPN11 result in human developmental disorders with overlapping clinical manifestations. Here, we uncover a common liquid-liquid phase separation (LLPS) behavior shared by these disease-associated SHP2 mutants.

Discovery of Pyrido[2,3-]indole Derivatives with Gram-Negative Activity Targeting Both DNA Gyrase and Topoisomerase IV.

The rise of multidrug resistant (MDR) Gram-negative (GN) pathogens and the decline of available antibiotics that can effectively treat these severe infections are a major threat to modern medicine. Developing novel antibiotics against MDR GN pathogens is particularly difficult as compounds have to permeate the GN double membrane, which has very different physicochemical properties, and have to circumvent a plethora of resistance mechanisms such as multiple efflux pumps and target modifications. The bacterial type II topoisomerases DNA gyrase (GyrAB) and Topoisomerase IV (ParCE) are highly conserved targets across all bacterial species and validated in the clinic by the fluoroquinolones.

Small Molecule Dysregulation of TEAD Lipidation Induces a Dominant-Negative Inhibition of Hippo Pathway Signaling.

The transcriptional enhanced associate domain (TEAD) family of transcription factors serves as the receptors for the downstream effectors of the Hippo pathway, YAP and TAZ, to upregulate the expression of multiple genes involved in cellular proliferation and survival. Recent work identified TEAD S-palmitoylation as critical for protein stability and activity as the lipid tail extends into a hydrophobic core of the protein. Here, we report the identification and characterization of a potent small molecule that binds the TEAD lipid pocket (LP) and disrupts TEAD S-palmitoylation.

Discovery of 3-Pyridyl Isoindolin-1-one Derivatives as Potent, Selective, and Orally Active Aldosterone Synthase (CYP11B2) Inhibitors.

Aldosterone synthase (CYP11B2) inhibitors have been explored in recent years as an alternative therapeutic option to mineralocorticoid receptor (MR) antagonists to reduce elevated aldosterone levels, which are associated with deleterious effects on various organ systems including the heart, vasculature, kidney, and central nervous system (CNS). A benzamide pyridine hit derived from a focused screen was successfully developed into a series of potent and selective 3-pyridyl isoindolin-1-ones CYP11B2 inhibitors. Our systematic structure-activity relationship study enabled us to identify unique structural features that result in high selectivity against the closely homologous cortisol synthase (CYP11B1).

Synthesis of NH-Sulfoximines by Using Recyclable Hypervalent Iodine(III) Reagents under Aqueous Micellar Conditions.

The synthesis of NH-sulfoximines from sulfides has been first developed under mild conditions in an aqueous solution with surfactant TPGS-750-M as the catalyst at room temperature. In this newly developed process, a simple and convenient recycling strategy to regenerate the indispensable hypervalent iodine(III) is used. The resulting 1,2,3-trifluoro-5-iodobezene can be recovered almost quantitively from the mixture by liquid-liquid extraction and then oxidized to give the corresponding iodine(III) species.

A New Approach of Mitigating CYP3A4 Induction Led to the Discovery of Potent Hepatitis B Virus (HBV) Capsid Inhibitor with Optimal ADMET Profiles.

Described herein is a new approach to mitigate CYP3A4 induction. In this unconventional approach, a fine-tuning of the dihedral angle between the C4 phenyl and the dihydropyrimidine core of the heteroaryldihydropyrimidine (HAP) class of capsid inhibitors successfully altered the structure-activity-relationships (SARs) of the unwanted CYP3A4 induction and the desired HBV capsid inhibition to more favorable values. This eventually led to the discovery of a new capsid inhibitor with significantly reduced CYP3A4 induction, excellent anti-HBV activity, favorable preclinical PK/PD profiles, and no early safety flags.

synthesis, structural assignment and biological evaluation of pseudopaline, a metallophore produced by .

Pseudopaline is an opine carboxylate metallophore produced by for harvesting divalent metals. However, the structure of pseudopaline is not fully elucidated. Herein, we report the first total synthesis and isolation of pseudopaline, which allows unambiguous determination and confirmation of both the absolute and the relative configuration of the natural product.

Discovery of (aza)indole derivatives as novel respiratory syncytial virus fusion inhibitors.

A new class of indole derivatives () have been identified as potent RSV fusion inhibitors. SAR exploration revealed that 5-Cl and the sulfonyl side chain of the indole scaffold are crucial for anti-RSV activity. Further optimization led to the discovery of a cyclic sulfone () with 2 nM anti-RSV activity and a much improved PK profile compared to the non-cyclic sulfone counterpart.

Discovery of Ziresovir as a Potent, Selective, and Orally Bioavailable Respiratory Syncytial Virus Fusion Protein Inhibitor.

Ziresovir (RO-0529, AK0529) is reported here for the first time as a promising respiratory syncytial virus (RSV) fusion (F) protein inhibitor that currently is in phase 2 clinical trials. This article describes the process of RO-0529 as a potent, selective, and orally bioavailable RSV F protein inhibitor and highlights the in vitro and in vivo anti-RSV activities and pharmacokinetics in animal species. RO-0529 demonstrates single-digit nM EC potency against laboratory strains, as well as clinical isolates of RSV in cellular assays, and more than one log viral load reduction in BALB/c mouse model of RSV viral infection.

Discovery of Benzoazepinequinoline (BAQ) Derivatives as Novel, Potent, Orally Bioavailable Respiratory Syncytial Virus Fusion Inhibitors.

A novel benzoazepinequnoline (BAQ) series was discovered as RSV fusion inhibitors. BAQ series originated from compound 2, a hit from similarity-based virtual screening. In SAR exploration, benzoazepine allowed modifications in the head moiety.

Discovery of RG7834: The First-in-Class Selective and Orally Available Small Molecule Hepatitis B Virus Expression Inhibitor with Novel Mechanism of Action.

Chronic hepatitis B virus (HBV) infection is a serious public health burden, and current therapies cannot achieve satisfactory cure rate. There are high unmet medical needs of novel therapeutic agents with differentiated mechanism of action (MOA) from the current standard of care. RG7834, a compound from the dihydroquinolizinone (DHQ) chemical series, is a first-in-class highly selective and orally bioavailable HBV inhibitor which can reduce both viral antigens and viral DNA with a novel mechanism of action.

Potassium Iodide-Promoted One-Pot Synthesis of Fluoroalkylated Quinoxalines via a Tandem Michael Addition/Azidation/Cycloamination Approach.

Fluoroalkylated quinoxlines with various groups were efficiently synthesized via a one-pot tandem Michael addition/azidation/cycloamination process. Under the mild and metal-free conditions, a bis-imine intermediate (4a) was detected and isolated for the first time. KI played a crucial role in this reaction.

Highly Chemo- and Regioselective Vinylation of N-Heteroarenes with Vinylsulfonium Salts.

An efficient chemo- and regioselective N-vinylation of N-heteroarenes has been developed using vinylsulfonium salts. The reaction proceeded under mild and transition-metal-free conditions and consistently provided moderate to high yields of vinylation products with 100% E-stereoselectivity. This reaction is also highly chemoselective, and compatible with a variety of functional groups, such as -NHR, -NH, -OH, -COOH, ester, etc.

Discovery of Small Molecule Therapeutics for Treatment of Chronic HBV Infection.

The chronic infection of hepatitis B virus (HBV) inflicts 250 million people worldwide representing a major public health threat. A significant subpopulation of patients eventually develop cirrhosis and hepatocellular carcinoma (HCC). Unfortunately, none of the current standard therapies for chronic hepatitis B (CHB) result in a satisfactory clinical cure rate.

Palladium-Catalyzed Difluoromethylation of Aryl Chlorides and Triflates and Its Applications in the Preparation of Difluoromethylated Derivatives of Drug/Agrochemical Molecules.

A palladium-catalyzed difluoromethylation of a series of aryl chlorides and triflates under mild conditions was described. A variety of common functional groups were tolerated. In addition, by using this protocol, several drug molecules containing an aryl chloride unit were successfully difluoromethylated, thus enabling medicinal chemists to rapidly access novel drug derivatives with potentially improved properties via late-stage functionalization.

C-H Bond Functionalization of Tetrahydropyridopyrimidines and Other Related Hetereocycles.

A novel and efficient 2-step method for the functionalization of the C-H bond adjacent to the amino group of tetrahydropyridopyrimidine (THPP) is reported herein. The reaction features mild conditions and excellent tolerance of a wide range of functional groups. Moreover, this method is applicable to tetrahydroisoquinolone (THIQ), which provides a useful supplement to literature method.

Discovery of methylsulfonyl indazoles as potent and orally active respiratory syncytial Virus(RSV) fusion inhibitors.

Recently we described a novel class of imidazopyridine compounds that showed exceptional anti-RSV potency in cell culture. However, unfavorable pharmacokinetic (PK) properties and glutathione (GSH) adduct liabilities impeded their further development. In a bid to address the PK and early safety concerns, a small compound library consisting of dozens of scaffold-hopping analogues was designed and synthesized for RSV CPE assay screening, which led to the identification of a new chemical starting point: methylsulfonyl indole compound 8.

Discovery and Pre-Clinical Characterization of Third-Generation 4-H Heteroaryldihydropyrimidine (HAP) Analogues as Hepatitis B Virus (HBV) Capsid Inhibitors.

Described herein are the discovery and structure-activity relationship (SAR) studies of the third-generation 4-H heteroaryldihydropyrimidines (4-H HAPs) featuring the introduction of a C6 carboxyl group as novel HBV capsid inhibitors. This new series of 4-H HAPs showed improved anti-HBV activity and better drug-like properties compared to the first- and second-generation 4-H HAPs. X-ray crystallographic study of analogue 12 (HAP_R01) with Cp149 Y132A mutant hexamer clearly elucidated the role of C6 carboxyl group played for the increased binding affinity, which formed strong hydrogen bonding interactions with capsid protein and coordinated waters.