Discovery of Beclabuvir: A Potent Allosteric Inhibitor of the Hepatitis C Virus Polymerase

Identification of Novel Cyclobutane-Based Derivatives as Potent Acetyl-CoA Carboxylase Allosteric Inhibitors for Nonalcoholic Steatohepatitis Drug Discovery

Nonalcoholic steatohepatitis (NASH) has become a leading cause of liver fibrosis and hepatocellular carcinoma; however, there are no efficient drugs for NASH therapy. Acetyl-CoA carboxylase (ACC) is a crucial enzyme regulating lipid metabolism that is considered as a potential target for NASH treatment. Allosteric inhibitors target nonfunctional sites, which tend to be highly variable in protein families; thus, allosteric inhibitors are explored as an important source of drug candidates. Herein, several hotspot residues are initially identified by utilizing molecular dynamic simulation, MM-GBSA calculation, and alanine mutation. Then, focusing on the interaction with hotspot residues, several cyclobutane-based ACC allosteric inhibitors are designed, synthesized, and biologically evaluated. Among them, B1 demonstrates potent ACC inhibitory activity in vitro, a higher distribution in liver than in other tissues, and a potent therapeutic effect for NASH in vivo, making it a promising candidate for the treatment of NASH.

Applications of Bridgehead Heterocycles in Drug Design and Medicinal Chemistry

Bridged heterocycles are highly relevant in medicinal chemistry and drug discovery due to the unique features associated with their three-dimensional configuration that ensures great scaffold complexity. In general, inserting bridged systems into a chemical structure positively influences the pharmacokinetic (PK) profile of leads, reducing lipophilicity and enhancing metabolic stability. Several optimization studies show that bridged systems often promoted a significant improvement of the small molecule-enzyme binding interaction due to conformational changes within the biological target active site. To date, many drugs including bridged cores are available in the market to cure several diseases. Given the broad range of biological activities of naturally occurring and (semi)-synthetic bridgehead heterocycles, here, we have thoroughly reviewed the rational design and the structure-activity relationship (SAR) studies of the most remarkable bridged compounds developed during the past decade, to highlight both the chemical and biological roles of these motifs.

An Exploration of the Inhibitory Mechanism of Rationally Screened Benzofuran-1,3,4-Oxadiazoles and-1,2,4-Triazoles as Inhibitors of NS5B RdRp Hepatitis C Virus through Pharmacoinformatic Approaches

Benzofuran, 1,3,4-oxadiazole, and 1,2,4-triazole are privileged heterocyclic moieties that display the most promising and wide spectrum of biological activities against a wide variety of diseases. In the current study, benzofuran-1,3,4-oxadiazole BF1-BF7 and benzofuran-1,2,4-triazole compounds BF8-BF15 were tested against HCV NS5B RNA-dependent RNA polymerase (RdRp) utilizing structure-based screening via a computer-aided drug design (CADD) approach. A molecular docking approach was applied to evaluate the binding potential of benzofuran-appended 1,3,4-oxadiazole and 1,2,4-triazole BF1-BF15 molecules. Benzofuran-1,3,4-oxadiazole scaffolds BF1-BF7 showed lesser binding affinities (-12.63 to -14.04 Kcal/mol) than benzofuran-1,2,4-triazole scaffolds BF8-BF15 (-14.11 to -16.09 Kcal/mol) against the HCV NS5B enzyme. Molecular docking studies revealed the excellent binding affinity scores exhibited by benzofuran-1,2,4-triazole structural motifs BF-9 (-16.09 Kcal/mol), BF-12 (-15.75 Kcal/mol), and BF-13 (-15.82 Kcal/mol), respectively, which were comparatively better than benzofuran-based HCV NS5B inhibitors' standard reference drug Nesbuvir (-15.42 Kcal/mol). A molecular dynamics simulation assay was also conducted to obtain valuable insights about the enzyme-compounds interaction profile and structural stability, which indicated the strong intermolecular energies of the BF-9+NS5B complex and the BF-12+NS5B complex as per the MM-PBSA method, while the BF-12+NS5B complex was the most stable system as per the MM-GBSA calculation. The drug-likeness and ADMET studies of all the benzofuran-1,2,4-triazole derivatives BF8-BF15 revealed that these compounds possessed good medicinal chemistry profiles in agreement with all the evaluated parameters for being drugs. The molecular docking affinity scores, MM-PBSA/MM-GBSA and MD-simulation stability analysis, drug-likeness profiling, and ADMET study assessment indicated that N-4-fluorophenyl-S-linked benzofuran-1,2,4-triazole BF-12 could be a future promising anti-HCV NS5B RdRp inhibitor therapeutic drug candidate that has a structural agreement with the Nesbuvir standard reference drug.

Palladium-Catalyzed [5 + 2] Rollover Annulation of 1-Benzylpyrazoles with Alkynes: A Direct Entry to Tricyclic 2-Benzazepines

The first Pd-catalyzed [5 + 2] rollover annulation of 1-benzylpyrazoles with alkynes to assemble 10H-benzo[e]pyrazolo[1,5-a]azepines (tricyclic 2-benzazepines) has been developed. The rollover annulation implies a twofold C-H activation of aryl and heteroaryl C_sp²-H bonds (C-H/C-H) of 1-benzylpyrazoles (five-atom partners) and alkynes to give the [5 + 2] annulated compounds.

Highly Antiproliferative Latonduine and Indolo[2,3-c]quinoline Derivatives: Complex Formation with Copper(II) Markedly Changes the Kinase Inhibitory Profile

A series of latonduine and indoloquinoline derivatives HL¹–HL⁸ and their copper(II) complexes (1–8) were synthesized and comprehensively characterized. The structures of five compounds (HL⁶, [CuCl(L¹)(DMF)]·DMF, [CuCl(L²)(CH₃OH)], [CuCl(L³)]·0.5H₂O, and [CuCl₂(H₂L⁵)]Cl·2DMF) were elucidated by single crystal X-ray diffraction. The copper(II) complexes revealed low micro- to sub-micromolar IC₅₀ values with promising selectivity toward human colon adenocarcinoma multidrug-resistant Colo320 cancer cells as compared to the doxorubicin-sensitive Colo205 cell line. The lead compounds HL⁴ and 4 as well as HL⁸ and 8 induced apoptosis efficiently in Colo320 cells. In addition, the copper(II) complexes had higher affinity to DNA than their metal-free ligands. HL⁸ showed selective inhibition for the PIM-1 enzyme, while 8 revealed strong inhibition of five other enzymes, i.e., SGK-1, PKA, CaMK-1, GSK3β, and MSK1, from a panel of 50 kinases. Furthermore, molecular modeling of the ligands and complexes showed a good fit to the binding pockets of these targets.

Antiviral and Antimicrobial Nucleoside Derivatives: Structural Features and Mechanisms of Action

The emergence of new viruses and resistant strains of pathogenic microorganisms has become a powerful stimulus in the search for new drugs. Nucleosides are a promising class of natural compounds, and more than a hundred drugs have already been created based on them, including antiviral, antibacterial and antitumor agents. The review considers the structural and functional features and mechanisms of action of known nucleoside analogs with antiviral, antibacterial or antiprotozoal activity. Particular attention is paid to the mechanisms that determine the antiviral effect of nucleoside analogs containing hydrophobic fragments. Depending on the structure and position of the hydrophobic substituent, such nucleosides can either block the process of penetration of viruses into cells or inhibit the stage of genome replication. The mechanisms of inhibition of viral enzymes by compounds of nucleoside and non-nucleoside nature have been compared. The stages of creation of antiparasitic drugs, which are based on the peculiarities of metabolic transformations of nucleosides in humans body and parasites, have been considered. A new approach to the creation of drugs is described, based on the use of prodrugs of modified nucleosides, which, as a result of metabolic processes, are converted into an effective drug directly in the target organ or tissue. This strategy makes it possible to reduce the general toxicity of the drug to humans and to increase the effectiveness of its action on cells infected by the virus.