Phenylpyrazolone-1,2,3-triazole Hybrids as Potent Antiviral Agents with Promising SARS-CoV-2 Main Protease Inhibition Potential

Exploring of N-phthalimide-linked 1,2,3-triazole analogues with promising -anti-SARS-CoV-2 activity: synthesis, biological screening, and molecular modelling studies

In this study, a library of phthalimide Schiff base linked to 1,4-disubstituted-1,2,3-triazoles was designed, synthesised, and characterised by different spectral analyses. All analogues have been introduced for in vitro assay of their antiviral activity against COVID-19 virus using Vero cell as incubator with different concentrations. The data revealed most of these derivatives showed potent cellular anti-COVID-19 activity and prevent viral growth by more than 90% at two different concentrations with no or weak cytotoxic effect on Vero cells. Furthermore, in vitro assay was done against this enzyme for all analogues and the results showed two of them have IC50 data by 90 µM inhibitory activity. An extensive molecular docking simulation was run to analyse their antiviral mechanism that found the proper non-covalent interaction within the Mpro protease enzyme. Finally, we profiled two reversible inhibitors, COOH and F substituted analogues that might be promising drug candidates for further development have been discovered.

Antiviral activity of pyrazole derivatives bearing a hydroxyquinoline scaffold against SARS-CoV-2, HCoV-229E, MERS-CoV, and IBV propagation

The ongoing global threat posed by coronaviruses necessitates the urgent development of effective antiviral agents. In this study, we investigated the potential of hydroxyquinoline-pyrazole candidates as antiviral agents against a range of coronaviruses, including SARS-CoV-2, MERS-CoV, and HCoV-229E. Molecular docking studies were conducted to assess the binding affinity of the synthesized compounds to key viral proteins. The compounds were prepared via condensation reactions of a pyrazolylhydrazide derivative with 2-chloro-3-formylquinoline, yielding hydrazone and pyrrolone derivatives. The cytotoxicity of compounds was evaluated using Vero E6 cells, and their antiviral activity was assessed via plaque reduction assays and viral inhibition assays using hydroxychloroquine as a positive control antiviral drug. The results revealed promising antiviral activity of the synthesized compounds against all tested coronaviruses, with selectivity indices indicating their potential as selective antiviral agents. Notably, the compounds exhibited potent inhibition of SARS-CoV-2 at lower concentrations, highlighting their promise as therapeutic candidates against this highly pathogenic virus. Likewise, the modeling pharmacokinetics approach showed its appropriate drug-likeness and bioavailability assets. These findings underscore the importance of hydroxyquinoline-pyrazole derivatives as potential antiviral agents against diverse coronaviruses, providing valuable insights for further therapeutic development.

Design and synthesis of chromene-1,2,3-triazole benzene sulfonamide hybrids as potent carbonic anhydrase-IX inhibitors against prostate cancer

Considering the promising effects of molecular hybridization on drug discovery in recent years and the ongoing endeavors to develop bioactive scaffolds tethering the 1,2,3-triazole core, the present study sought to investigate whether the 1,2,3-triazole-linked chromene and benzene sulfonamide nucleus could exhibit activity against the human breast cancer cell line MCF-7 and prostate cancer cell line PC-3. To this end, three focused bioactive series of mono- and -bis-1,2,3-triazoles were effectively synthesized via copper-assisted cycloaddition of mono- and/or di-alkyne chromenone derivatives 2a and b and 9 with several sulfa drug azides 4a-d and 6. The resulting molecular derivatives were tested for cytotoxicity against prostate and breast cancer cells. Among the derivatives, 10a, 10c, and 10e exhibited potent cytotoxicity against PC-3 cells with IC50 values of 2.08, 7.57, and 5.52 μM compared to doxorubicin (IC50 = 2.31 μM) with potent inhibition of CA IX with IC50 values of 0.113, 0.134, and 0.214 μM. The most active compound, 10a, was tested for apoptosis-induction; it induced apoptosis by 31.9-fold cell cycle arrest at the G1-phase. Further, the molecular modeling approach highlighted the relevant binding affinity for the top-active compound 10a against CA IX as one of the most prominent PC-3 prostate cancer-associated biotargets.

A Metal-Free Cycloaddition of α-Diazoacetates with Amino Acid-Derived NHPI Esters for the Facile Synthesis of 1,2,4-Triazoles

1,2,4-Triazoles are privileged scaffolds for many pharmaceuticals, and methods for structurally diverse compound libraries are of current interest. Here we report an efficient coupling of α-diazoacetates with amino acid-derived alkyl N-hydroxy phthalimide esters, under metal-free conditions involving 1,8-diazabicyclo(5.4.0)undec-7-ene as the base, with which highly functionalized 1,2,4-triazoles can be obtained in excellent yields with remarkable functional group tolerance. Preliminary studies revealed that 1,2,4-triazole 3a exhibits potent inhibition of tyrosinase activities in melanoma B16F10 cell lines, demonstrating promising skin-whitening properties.

Introducing the antibacterial and photocatalytic degradation potentials of biosynthesized chitosan, chitosan-ZnO, and chitosan-ZnO/PVP nanoparticles

The development of nanomaterials has been speedily established in recent years, yet nanoparticles synthesized by traditional methods suffer unacceptable toxicity and the sustainability of the procedure for synthesizing such nanoparticles is inadequate. Consequently, green biosynthesis, which employs biopolymers, is gaining attraction as an environmentally sound alternative to less sustainable approaches. Chitosan-encapsulated nanoparticles exhibit exceptional antibacterial properties, offering a wide range of uses. Chitosan, obtained from shrimp shells, aided in the environmentally friendly synthesis of high-purity zinc oxide nanoparticles (ZnO NPs) with desirable features such as the extraction yield (41%), the deacetylation (88%), and the crystallinity index (74.54%). The particle size of ZnO NPs was 12 nm, while that of chitosan-ZnO NPs was 21 nm, and the bandgap energies of these nanomaterials were 3.98 and 3.48, respectively. The strong antibacterial action was demonstrated by ZnO NPs, chitosan-ZnO NPs, and chitosan-ZnO/PVP, particularly against Gram-positive bacteria, making them appropriate for therapeutic use. The photocatalytic degradation abilities were also assessed for all nanoparticles. At a concentration of 6 × 10-5 M, chitosan removed 90.5% of the methylene blue (MB) dye, ZnO NPs removed 97.4%, chitosan-coated ZnO NPs removed 99.6%, while chitosan-ZnO/PVP removed 100%. In the case of toluidine blue (TB), at a concentration of 4 × 10-3 M, the respective efficiencies were 96.8%, 96.8%, 99.5%, and 100%, respectively. Evaluation of radical scavenger activity revealed increased scavenging of ABTS and DPPH radicals by chitosan-ZnO/PVP compared to individual zinc oxide or chitosan-ZnO, where the IC50 results were 0.059, 0.092, 0.079 mg/mL, respectively, in the ABTS test, and 0.095, 0.083, 0.061, and 0.064 mg/mL in the DPPH test, respectively. Moreover, in silico toxicity studies were conducted to predict the organ-specific toxicity through ProTox II software. The obtained results suggest the probable safety and the absence of organ-specific toxicity with all the tested samples.

Design, synthesis, and molecular modeling studies of novel 2-quinolone-1,2,3-triazole-α-aminophosphonates hybrids as dual antiviral and antibacterial agents

With the aim to identify new antiviral agents with antibacterial properties, a series of 2-quinolone-1,2,3-triazole derivatives bearing α-aminophosphonates was synthesized and characterized by 1H NMR, 13C NMR, 31P NMR, single crystal XRD and HRMS analyses. These compounds were examined against five RNA viruses (YFV, ZIKV, CHIKV, EV71 and HRV) from three distinct families (Picornaviridae, Togaviridae and Flaviviridae) and four bacterial strains (S. aureus, E. feacalis, E. coli and P. aeruginosa). The α-aminophosphonates 4f, 4i, 4j, 4k, 4p and 4q recorded low IC50 values of 6.8-10.91 μM, along with elevated selectivity indices ranging from 2 to more than 3, particularly against YFV, CHIKV and HRV-B14. Besides, the synthesized compounds were generally more sensitive toward Gram-positive bacteria, with the majority of them displaying significant potency against E. feacalis. Specifically, an excellent anti-enterococcus activity was obtained by compound 4q with MIC and MBC values of 0.03 μmol/mL, which were 8.7 and 10 times greater than those of the reference drugs ampicillin and rifampicin, respectively. Also, compounds 4f, 4p and 4q showed potent anti-staphylococcal activity with MIC values varying between 0.11 and 0.13 μmol/mL, compared to 0.27 μmol/mL for ampicillin. The results from DFT and molecular docking simulations were in agreement with the biological assays, proving the binding capability of hybrids 4f, 4i, 4j, 4k, 4p and 4q with viral and bacterial target enzymes through hydrogen bonds and other non-covalent interactions. The in silico ADME/Tox prediction revealed that these molecules possess moderate to good drug-likeness and pharmacokinetic properties, with a minimal chance of causing liver toxicity or carcinogenic effects.

NeuroClick: software for mimicking click reaction to generate drug-like molecules permeating the blood-brain barrier

Background: Traditional methods for chemical library generation in virtual screening often impose limitations on the accessible chemical space or produce synthetically irrelevant structures. Incorporating common chemical reactions into generative algorithms could offer significant benefits. Materials & methods: In this study, we developed NeuroClick, a graphical user interface software designed to perform in silico azide-alkyne cycloaddition, a widely utilized synthetic approach in modern medicinal chemistry. Results & conclusion: NeuroClick facilitates the generation and filtering of large combinatorial libraries at a remarkable rate of 10,000 molecules per minute. Moreover, the generated products can be filtered to identify subsets of pharmaceutically relevant compounds based on Lipinski's rule of five and blood-brain barrier permeability prediction. We demonstrate the utility of NeuroClick by generating and filtering several thousand molecules for dopamine D3 receptor ligand screening.

Click chemistry-aided drug discovery: A retrospective and prospective outlook

Click chemistry has emerged as a valuable tool for rapid compound synthesis, presenting notable advantages and convenience in the exploration of potential drug candidates. In particular, in situ click chemistry capitalizes on enzymes as reaction templates, leveraging their favorable conformation to selectively link individual building blocks and generate novel hits. This review comprehensively outlines and introduces the extensive use of click chemistry in compound library construction, and hit and lead discovery, supported by specific research examples. Additionally, it discusses the limitations and precautions associated with the application of click chemistry in drug discovery. Our intention for this review is to contribute to the development of a modular synthetic approach for the rapid identification of drug candidates.

Novel benzochromenes: design, synthesis, cytotoxicity, molecular docking and mechanistic investigations

Aim: A novel series of fused benzochromenes with expected cytotoxicity and HIF-1α inhibition was identified. Materials & methods: A bioisosterism-aided approach was applied to design new benzochromenes and assess their cytotoxicity against three cancer cell lines. The probable mechanistic effect and the in silico docking and pharmacokinetic profiles of the most effective derivatives were evaluated. Results: Compounds 3, 4, 5, 8 and 11 showed potent antiproliferative activity and excellent selectivity. Compound 8 showed significant HIF-1α inhibition with an IC50 value of 3.372 μM. It also enhanced apoptosis and arrested the HepG2 cell cycle at both the G0/G1 and S stages. Conclusion: Compound 8 was identified as a new potential anticancer candidate.

Molecular overlay-guided design of new CDK2 inhibitor thiazepinopurines: Synthesis, anticancer, and mechanistic investigations

Adopting the molecular overlay approach, three novel sets of thiazepinopurines with expected cytotoxicity and CDK2 inhibition potential were designed and synthesized. This was accomplished through the heteroannelation of purines, for the first time, with thiazepine. The obtained thiazepinopurines derivatives were assessed for their cytotoxicity toward tumor cells of three different types, HepG2, MCF-7, and PC-3 as well as one normal cell (WI38). Among the studied compounds, 3b and 3c exhibited significant antiproliferative activity against tumor cells presenting IC50 range of 5.52-17.09 µM in comparison with Roscovitine (9.32-13.82 µM). Additionally, both compounds displayed superior selectivity indices (SI = 3.00-7.15) toward tested cancer cells. The 4-chlorophenyl analog 3b has shown the best selectivity index, and hence it has been subjected to additional investigations to determine its proper mechanistic effect. Accordingly, the CDK2 inhibition potential, apoptosis induction, and cell cycle analysis of MCF-7 were evaluated. Results revealed that this analog displayed a potent CDK2 inhibition potential with an IC50 value of 0.219 µM. Findings also showed that 3b was thought to arrest MCF-7 cell cycle at S phase together with apoptosis induction by the increased expression of Bax, Caspase-8, and -9 markers with a concomitant decrease in Bcl-2 expression. Besides, the probable interaction of 3b with CDK2 binding pocket was investigated by molecular docking.

Benzimidazole-Triazole Hybrids as Antimicrobial and Antiviral Agents: A Systematic Review

Bacterial infections have attracted the attention of researchers in recent decades, especially due to the special problems they have faced, such as their increasing diversity and resistance to antibiotic treatment. The emergence and development of the SARS-CoV-2 infection stimulated even more research to find new structures with antimicrobial and antiviral properties. Among the heterocyclic compounds with remarkable therapeutic properties, benzimidazoles, and triazoles stand out, possessing antimicrobial, antiviral, antitumor, anti-Alzheimer, anti-inflammatory, analgesic, antidiabetic, or anti-ulcer activities. In addition, the literature of the last decade reports benzimidazole-triazole hybrids with improved biological properties compared to the properties of simple mono-heterocyclic compounds. This review aims to provide an update on the synthesis methods of these hybrids, along with their antimicrobial and antiviral activities, as well as the structure-activity relationship reported in the literature. It was found that the presence of certain groups grafted onto the benzimidazole and/or triazole nuclei (-F, -Cl, -Br, -CF₃, -NO₂, -CN, -CHO, -OH, OCH₃, COOCH₃), as well as the presence of some heterocycles (pyridine, pyrimidine, thiazole, indole, isoxazole, thiadiazole, coumarin) increases the antimicrobial activity of benzimidazole-triazole hybrids. Also, the presence of the oxygen or sulfur atom in the bridge connecting the benzimidazole and triazole rings generally increases the antimicrobial activity of the hybrids. The literature mentions only benzimidazole-1,2,3-triazole hybrids with antiviral properties. Both for antimicrobial and antiviral hybrids, the presence of an additional triazole ring increases their biological activity, which is in agreement with the three-dimensional binding mode of compounds. This review summarizes the advances of benzimidazole triazole derivatives as potential antimicrobial and antiviral agents covering articles published from 2000 to 2023.

Aminopyridone-linked benzimidazoles: a fragment-based drug design for the development of CDK9 inhibitors

Aim: A fragment-based design and synthesis of three novel series of aminopyridone-linked benzimidazoles as potential anticancer candidates with significant CDK9 inhibition was implemented. Materials & methods: All synthesized compounds were submitted to National Cancer Institute, 60 cell lines and seven-dose cytotoxicity toward three cancer cells. Results: Compounds 2, 4a, 4c, 4d, 6a and 8a exhibited significant cytotoxicity and selectivity with IC50 range of 7.61-57.75 μM. Regarding the mechanism either in vitro or in silico, 4a, 6a and 8a displayed potent CDK9 inhibition with IC50 value of 0.424-8.461 μM. Compound 6a arrested the cell cycle at S phase and induced apoptosis in MCF-7 cells. Conclusion: Compound 6a is a promising CDK9 inhibitor that warrants additional research for cancer treatment.