Pyrazolo[3,4-d]pyrimidine derivatives containing a Schiff base moiety as potential antiviral agents

Acyl hydrazone derivatives with trifluoromethylpyridine as potential agrochemical for controlling plant diseases

BACKGROUND

Crops are consistently under siege by a multitude of pathogens. These pathogenic microorganisms, including viruses and bacteria, result in substantial reductions in quality and yield globally by inducing detrimental crop diseases, thus posing a significant challenge to global food security. However, the biological activity sepectrum of commercially available pesticides is limited and the pesticide efficacy is poor, necessitating the urgent development of broad-spectrum and efficient strategies for crop disease prevention and control.

RESULTS

The bioassay results revealed that certain target compounds demonstrated outstanding in vivo antiviral efficacy against cucumber mosaic virus and tobacco mosaic virus. In particular, compound D6 showed remarkable antiviral activity against CMV, significantly higher than that of the control agent ningnanmycin. Mechanism of action studies have shown that compound D6 could enhance the activity of defense enzymes and upregulate the expression of genes related to disease resistance, thereby enhancing the antiviral effects in plants. In addition, these compounds displayed superior inhibitory activity against plant bacterial diseases. For Xoo, compound D10 showed an excellent inhibitory effect that was better than that of the control agent bismerthiazol. Scanning electron microscopy and fluorescence double-staining experiments revealed that compound D10 effectively inhibited bacterial growth by disrupting the cell membrane.

CONCLUSION

A series of trifluoromethyl hydrazone derivatives were designed and synthesized, and it was found that they have control effects on plant viruses and bacterial diseases. In addition, this study revealed the mechanism of action of the active compounds and demonstrated their potential as multifunctional crop protectants. © 2024 Society of Chemical Industry.

Antiviral activity evaluation and action mechanism of myricetin derivatives containing thioether quinoline moiety

A variety of myricetin derivatives containing thioether quinoline moiety were designed and synthesized. Their structures of title compounds were determined by 1H NMR, 13C NMR, 19F NMR, and HRMS. Single-crystal X-ray diffraction experiments were carried out with B4. Antiviral activity indicated that some of the target compounds exhibited remarkable anti-tobacco mosaic virus (TMV) activity. In particular, compound B6 possessed significant activity. The half maximal effective concentration (EC50) value of the curative activity of compound B6 was 169.0 μg/mL, which was superior to the control agent ningnanmycin (227.2 μg/mL). Meanwhile, the EC50 value of the protective activity of compound B6 was 86.5 μg/mL, which was better than ningnanmycin (179.2 μg/mL). Microscale thermophoresis (MST) indicated that compound B6 had a strong binding capability to the tobacco mosaic virus coat protein (TMV-CP) with a dissociation constant (Kd) value of 0.013 μmol/L, which was superior to that of myricitrin (61.447 μmol/L) and ningnanmycin (3.215 μmol/L). And the molecular docking studies were consistent with the experimental results. Therefore, these novel myricetin derivatives containing thioether quinoline moiety could become potential alternative templates for novel antiviral agents.

Synthesis of 4H-Pyrazolo[3,4-d]pyrimidin-4-one Hydrazine Derivatives as a Potential Inhibitor for the Self-Assembly of TMV Particles

Tobacco mosaic virus coat protein (TMV-CP), as a potential target for the development of antiviral agents, can assist in the long-distance movement of viruses and plays an extremely important role in virus replication and propagation. This work focuses on the synthesis and the action mechanism of novel 4H-pyrazolo[3,4-d] pyrimidin-4-one hydrazine derivatives. The synthesized compounds exhibited promising antiviral activity on TMV. Specifically, compound G2 exhibited high inactivating activity (93%) toward TMV, slightly better than commercial reagent NNM (90%). The action of mechanism was further explored by employed molecular docking, molecular dynamics simulation, microscale thermophoresis, qRT-PCR, and transmission electron microscopy. Results indicated that G2 had the capability to interact with amino acid residues such as Trp352, Tyr139, and Asn73 in the active pocket of TMV-CP, creating strong hydrophobic interactions and thus obstructing the virus's self-assembly.

Flavonol Derivatives Containing a Quinazolinone Moiety: Design, Synthesis, and Antiviral Activity

A series of flavonol derivatives containing quinazolinone were designed and synthesized, and their antiviral activities against tobacco mosaic virus (TMV) were evaluated. The results of the half maximal effective concentration (EC50 ) test against TMV showed that the EC50 value of curative activity of K5 was 139.6 μg/mL, which was better than that of the commercial drug ningnanmycin (NNM) 296.0 μg/mL, and the EC50 value of protective activity of K5 was 120.6 μg/mL, which was superior to that of NNM 207.0 μg/mL. The interaction of K5 with TMV coat protein (TMV-CP) was investigated using microscale thermophoresis (MST) and molecular docking and the results showed that K5 can combine with TMV-CP more strongly to TMV-CP than that NNM can. Furthermore, the assay measuring malondialdehyde (MDA) content indicated that K5 had the ability to improve the disease resistance of tobacco. Hence, this study offers strong evidence that flavonol derivatives have potential as novel antiviral agents.

Novel pyrazolo[3,4-d]pyrimidine derivatives: design, synthesis, anticancer evaluation, VEGFR-2 inhibition, and antiangiogenic activity

A novel series of 12 pyrazolo[3,4-d]pyrimidine derivatives were created and evaluated in vitro for their antiproliferative activity against the NCI 60 human tumor cell line panel. Compounds 12a-d displayed significant antitumor activity against MDA-MB-468 and T-47D (breast cancer cell lines), especially compound 12b, which exhibited the highest anticancer activity against MDA-MB-468 and T-47D cell lines with IC50 values of 3.343 ± 0.13 and 4.792 ± 0.21 μM, respectively compared to staurosporine with IC50 values of 6.358 ± 0.24 and 4.849 ± 0.22 μM. The most potent cytotoxic derivatives 12a-d were studied for their VEGFR-2 inhibitory activity to explore the mechanism of action of these substances. Compound 12b had potent activity against VEGFR-2 with an IC50 value of 0.063 ± 0.003 μM, compared to sunitinib with IC50 = 0.035 ± 0.012 μM. Moreover, there was an excellent reduction in HUVEC migratory potential that resulted in a significant disruption of wound healing patterns by 23% after 72 h of treatment with compound 12b. Cell cycle and apoptosis investigations showed that compound 12b could stop the cell cycle at the S phase and significantly increase total apoptosis in the MDA-MB-468 cell line by 18.98-fold compared to the control. Moreover, compound 12b increased the caspase-3 level in the MDA-MB-468 cell line by 7.32-fold as compared to the control.

Synthesis, biological and molecular docking studies of pyrimidine-derived bioactive Schiff bases

Pyrimidine which is an important constituent of the genetic material of deoxyribonucleic acid, is identified with a large number of biological activities. Based on this, pyrimidine-derived Schiff bases (1-6) of hydroxy-1-naphthaldehyde were synthesized by using the condensation method. In addition, the molecular docking studies against topoisomerase II DNA gyrase, human hematopoietic cell kinase, urate oxidase from Aspergillus flavus, and cyclin-dependent kinase 8 to explore the antibacterial, antioxidant, antifungal, and anticancer properties respectively and binding affinities through bioinformatics approaches to determine the interaction among active molecules with the receptor. Hence, the computational docking analyses identified that all synthesized pyrimidine Schiff bases (1-6) are active and exhibited better binding affinities as compared to the standard drugs. Furthermore, all the prepared materials were characterized by using nuclear magnetic resonance, infrared, and elemental analysis. Additionally, the phase-transition and thermal decomposition temperatures were determined by differential scanning calorimetry and thermo-gravimetric analysis measurements. Moreover, the structures of pyrimidine-derived Schiff bases 1, 2, 3, 4, and 5 were also confirmed by the X-ray single-crystal diffraction technique. The pyrimidine-derived Schiff bases 5 possess significant antibacterial, antioxidant, antifungal, and anticancer agent properties which confirms its promising biological activities over standard drugs.

Synthesis of Schiff Bases and Secondary Amines with Indane Skeleton; Evaluation of Their Antioxidant, Antibiotic, and Antifungal Activities

In this study, Schiff bases were synthesized by utilizing the reaction of 4- and 5-aminoindane with substituted benzaldehydes. After the reduction of isolated Schiff bases with NaBH4 , the corresponding secondary amine derivatives were obtained. The structures of all synthesized molecules were confirmed by 1 H-NMR, 13 C-NMR, FT-IR, and ESI-MS. Antioxidant activities of all synthesized molecules were investigated by DPPH method, and IC50 values were calculated. In addition, antibacterial activities of targets were investigated by the well diffusion method, and then MIC99 values were calculated. While only four of the sixteen synthesized molecules showed a high level of antioxidant activity, all of the molecules exhibited biological activity against Gram-positive and Gram-negative bacteria to varying degrees. In addition, all the synthesized molecules showed high antifungal activity. In antioxidant capacity studies, the IC50 values of 2-(((2,3-dihydro-1H-inden-5-yl)amino)methyl)-6-methoxyphenol (4 d) and 2-(((2,3-dihydro-1H-inden-4-yl)amino)methyl)-6-methoxyphenol (7 d) were determined to be 18.1 μg and 35.1 μg, respectively, and these values are much stronger than BHT (butylated hydroxytoluene) and BHA (butylated hydroxyanisole) used as positive controls. The fact that targets have the same core structure with different substituents has revealed a good structure-activity relationship.

Comparing Singlet Oxygen Generation of Schiff Base Substituted Novel Silicon Phthalocyanines by Sonophotochemical and Photochemical Applications

Although the sonophotodynamic method has an effective therapeutic outcome for anticancer treatment compared with the photodynamic method, there are not enough related studies in the literature and this study aims to contribute to the development of sonophotodynamic studies. For this purpose, the Schiff base substituted silicon phthalocyanines were designed and synthesized as effective sensitizer candidates and the photophysicochemical and sonophotochemical features of the phthalocyanines were examined to increase singlet oxygen efficiency. The calculated ΦΔ values indicate that the contribution of substituent groups improved the production of singlet oxygen compared with silicon (IV) phthalocyanine dichloride (SiPcCI2 ) and also the sonophotochemical applications increased the singlet oxygen yields. The ΦΔ values (ΦΔ  = 0.76 for axially bis-{4-[(E)-(pyridin-3-ylimino)methyl]phenol} substituted silicon (IV) phthalocyanine (2a), 0.68 for axially bis-4-[(E)-{[(pyridin-3-yl)methyl]imino}methyl]phenol substituted silicon (IV) phthalocyanine (2b) in photochemical study) reached to ΦΔ  = 0.98 for 2a, 0.94 for 2b in sonophotochemical study. This article will enrich the literature on increasing singlet oxygen yield.

Design, synthesis and biological evaluation of dual Topo II/HDAC inhibitors bearing pyrimido[5,4-b]indole and pyrazolo[3,4-d]pyrimidine motifs

Both topoisomerase II (Topo II) and histone deacetylase (HDAC) are important therapeutic targets for cancer. In this study, two series of novel compounds containing pyrimido[5,4-b]indole and pyrazolo[3,4-d]pyrimidine motifs were designed and synthesized as dual Topo II/HDAC inhibitors. MTT assay indicated that all the compounds displayed potential antiproliferative activity against three cancer cell lines (MGC-803, MCF-7 and U937) and low cytotoxicity on normal cell line (3T3). In the enzyme activity inhibition experiments, compounds 7d and 8d exhibited excellent dual inhibitory activities against Topo II and HDAC. Cleavage reaction assay showed that 7d was a Topo II poison, which was consistent with the docking results. Further experimental results revealed that compounds 7d and 8d could promote apoptosis and significantly inhibit the migration in MCF-7 cells. Molecular docking showed that compounds 7d and 8d bind Topo II and HDAC at the active sites. Molecular dynamics simulation showed that 7d can stably bind to Topo II and HDAC.

Design, synthesis and bioactivity of myricetin derivatives for control of fungal disease and tobacco mosaic virus disease

A series of myricetin derivatives containing isoxazole were designed and synthesized. All the synthesized compounds were characterized by NMR and HRMS. In terms of antifungal activity, Y3 had a good inhibitory effect on Sclerotinia sclerotiorum (Ss), and the median effective concentration (EC₅₀) value was 13.24 μg mL^-1, which was better than azoxystrobin (23.04 μg mL^-1) and kresoxim-methyl (46.35 μg mL^-1). Release of cellular contents and cell membrane permeability experiments further revealed that Y3 causes the destruction of the cell membrane of the hyphae, which in turn plays an inhibitory role. The anti-tobacco mosaic virus (TMV) activity in vivo showed that Y18 had the best curative and protective activities, with EC₅₀ values of 286.6 and 210.1 μg mL^-1 respectively, the effect was better than ningnanmycin. Microscale thermophoresis (MST) data showed that Y18 had a strong binding affinity with tobacco mosaic virus coat protein (TMV-CP), with a dissociation constant (K _d) value of 0.855 μM, which was better than ningnanmycin (2.244 μM). Further molecular docking revealed that Y18 interacts with multiple key amino acid residues of TMV-CP, which may hinder the self-assembly of TMV particles. Overall, after the introduction of isoxazole on the structure of myricetin, its anti-Ss and anti-TMV activities have been significantly improved, which can be further studied.

Exploring the Antimicrobial and Pharmacological Potential of NF22 as a Potent Inhibitor of E. coli DNA Gyrase: An In Vitro and In Silico Study

Toward the search for novel antimicrobial agents to control pathogenic E. coli-associated infections, a series of novel norfloxacin derivatives were screened for antimicrobial activities. The norfloxacin derivative, 1-ethyl-6-fluoro-7-(4-(2-(2-(3-hydroxybenzylidene)hydrazinyl)-2-oxoethyl)piperazin-1-yl)-4-oxo-1,4-dihydroquinoline-3-carboxylic acid (NF22) demonstrated excellent antibacterial activities against E. coli ATCC 25922 (MIC = 0.0625 μg/mL) and MDR E. coli 1-3 (MIC = 1, 2 and 1 µg/mL). The time-kill kinetic studies have demonstrated that the NF22 was advantageous over norfloxacin and ciprofloxacin in killing the control and MDR E. coli strains. The checkerboard assay showed that NF22 in combination with tetracycline had a synergistic effect against the E. coli strains. The experimental findings are supported by molecular modeling studies on DNA gyrase, explaining the interactions involved for compound NF22, compared to norfloxacin and ciprofloxacin. Further, the compound was also evaluated for various pharmacokinetics (absorption, metabolism, distribution, toxicity and excretion) as well as drug-likeness properties. Our data have highlighted the potential of norfloxacin by restoring its efficacy against E. coli which could lead to the development of new antimicrobial agents.

Pyrimidine: An elite heterocyclic leitmotif in drug discovery-synthesis and biological activity

Heterocyclic compounds bearing the pyrimidine core are of tremendous interest as they constitute an important class of natural and synthetic compounds exhibiting diverse useful biological activities that hold attractive potential for clinical translation as therapeutic agents in alleviation of a myriad of diseases. Heterocycles possessing a pyrimidine scaffold have piqued tremendous interest of organic and medicinal chemists owing to their privileged bioactivities. Drugs having the pyrimidine motif have manifested to exhibit gratifying biological activity like anticancer, antiviral, anti-inflammatory, antibacterial, and antihypertensive activities. This heterocycle, being a significant endogenous component of the body, the pyrimidine derivatives can easily interact with enzymes, genetic materials, and bio components within the cell. The landscape of FDA approved drugs, presently marketed incorporating the pyrimidine scaffold continues to evolve in number and diversity. There is a tremendous surge in discovery of new targets across many diseases especially those involving emerging resistance to clinically used battery of drugs. Pyrimidine scaffolds will continue to be explored expanding their chemical space portfolio in an effort to find novel drugs impacting these targets. This review aims to provide an elaborate recapitulation of the recent trends adopted to synthesize propitious pyrimidine incorporated hits and also focuses on the clinical significance reported for functionalized pyrimidine analogues that would quintessentially aid medicinal chemists for new research explorations in this arena.

Synthesis and antiviral activity of diverse heterocyclic scaffolds

Heterocyclic moieties form a major part of organic chemistry as they are widely distributed in nature and have wide scale practical applications ranging from extensive clinical use to diverse fields such as medicine, agriculture, photochemistry, biocidal formulations, and polymer science. By virtue of their therapeutic properties, they could be employed in combating many infectious diseases. Among the common infectious diseases, viral infections are of great public health importance worldwide. Thus, there is an urgent need for the discovery and development of antiviral drugs and clinical methods to prevent various viral infections so as to increase the life expectancy. This review presents the comprehensive overview of the synthesis and antiviral activity of different heterocyclic compounds 2015 onwards, which aids in present knowledge and helps the researchers and other stakeholders to explore their field.

Green Synthesis, Characterization, Antimicrobial and Anticancer Screening of New Metal Complexes Incorporating Schiff Base

A Schiff base ligand of o-vanillin and 4-aminoazobenzene and its transition metal complexes of Ni(II), Co(II), Zn(II), Cu(II), Mn(II), and Zr(IV) were prepared under microwave irradiation as a green approach compared to the conventional method. The structures of new compounds have been characterized and elucidated via elemental and spectroscopic analyses. In addition, magnetic susceptibility, electron spin resonance, and electronic spectra of the synthesized complexes explained their geometrical structures. The thermal stability of Cu(II), Zn(II), and Zr(IV) complexes was studied by thermo-gravimetric analyses (TGA). Coats-Redfern and Horowitz-Metzger equations were used to calculate the thermal and dehydration decomposition activities of proposed structures kinetically. Surface morphologies of the solid compounds were imaged by scanning electron microscopy (SEM). The particle size of prepared complexes was measured by using a particle size analyzer at a diffraction angle of 10.9°. The geometry structures of the synthesized compounds were verified utilizing electronic spectra, ESR spectrum, and magnetic moment value. The newly synthesized compounds were screened for antimicrobial activity. Also, the anticancer activity of the free Schiff base ligand and its metal complexes were studied against two cell lines: human colon (HCT-116) and human liver cancer cells (HepG-2). The obtained results showed that the Cu(II) complex displayed the highest cytotoxic activity (IC₅₀ = 18 and 22 μg/mL for HepG-2 and HCT, respectively) compared to the free Schiff base ligand.

Plant Viral Coat Proteins as Biochemical Targets for Antiviral Compounds

Coat proteins (CPs) of RNA plant viruses play a pivotal role in virus particle assembly, vector transmission, host identification, RNA replication, and intracellular and intercellular movement. Numerous compounds targeting CPs have been designed, synthesized, and screened for their antiviral activities. This review is intended to fill a knowledge gap where a comprehensive summary is needed for antiviral agent discovery based on plant viral CPs. In this review, major achievements are summarized with emphasis on plant viral CPs as biochemical targets and action mechanisms of antiviral agents. This review hopefully provides new insights and references for the further development of new safe and effective antiviral pesticides.

Development of Metal Complexes for Treatment of Coronaviruses

Coronavirus disease (SARS-CoV-2) is a global epidemic. This pandemic, which has been linked to high rates of death, has forced some countries throughout the world to implement complete lockdowns in order to contain the spread of infection. Because of the advent of new coronavirus variants, it is critical to find effective treatments and vaccines to prevent the virus's rapid spread over the world. In this regard, metal complexes have attained immense interest as antibody modifiers and antiviral therapies, and they have a lot of promise towards SARS-CoV-2 and their suggested mechanisms of action are discussed, i.e., a new series of metal complexes' medicinal vital role in treatment of specific proteins or SARS-CoV-2 are described. The structures of the obtained metal complexes were fully elucidated by different analytical and spectroscopic techniques also. Molecular docking and pharmacophore studies presented that most of complexes studied influenced good binding affinity to the main protease SARS-CoV-2, which also was attained as from the RCSB pdb (Protein Data Bank) data PDB ID: 6 W41, to expect the action of metal complexes in contradiction of COVID-19. Experimental research is required to determine the pharmacokinetics of most of the complexes analyzed for the treatment of SARS-CoV-2-related disease. Finally, the toxicity of a metal-containing inorganic complex will thus be discussed by its capability to transfer metals which may bind with targeted site.

Trifluoromethylpyridine thiourea derivatives: design, synthesis and inhibition of the self-assembly of tobacco mosaic virus particles

BACKGROUND

Devastating plant virus diseases leading to bad harvests and lower quality of crops have made feeding the beyond seven billion population a huge challenge. Nevertheless, growing resistance and cross resistance of crop protection agents have made this challenge harder. Therefore, an efficient crop protection agent with novel structure and mode of action showing higher efficiency and eco-friendly is urgently needed.

RESULTS

The coat protein (CP) of a virus is a potential target for the discovery of new antiviral agents. Antiviral molecules can inhibit infection by obstructing the assembly of virus particles. A series of novel phthalamide-like thiourea derivatives containing trifluoromethylpyridine was designed and synthesized. Most of the compounds exhibited good antiviral activity against tobacco mosaic virus (TMV). Compound 7b showed notable curative, protective and inactivation activities against TMV. Its inactivation half-maximal effective concentration (EC₅₀ ) value (20.5 μg mL^-1 ) was better even than commercial ningnanmycin (23.2 μg mL^-1 ). Compound 7b also had stronger TMV-CP binding ability than ningnanmycin and destroyed the external shape of TMV particles and hindered the self-assembly of TMV-CP and TMV-RNA.

CONCLUSION

These phthalamide-like thiourea derivatives especially compound 7b containing trifluoromethylpyridine are potential lead compounds and inhibitors of TMV particle self-assembly. © 2021 Society of Chemical Industry.

Fabrication of Ceftriaxone-Loaded Cellulose Acetate and Polyvinyl Alcohol Nanofibers and Their Antibacterial Evaluation

Nanotechnology provides solutions by combining the fields of textiles and medicine to prevent infectious microbial spread. Our study aimed to evaluate the antimicrobial activity of nanofiber sheets incorporated with a well-known antibiotic, ceftriaxone. It is a third-generation antibiotic that belongs to the cephalosporin group. Different percentages (0, 5%, 10%, 15%, and 20%; based on polymer wt%) of ceftriaxone were incorporated with a polymer such as polyvinyl alcohol (PVA) via electrospinning to fabricate nanofiber sheets. The Kirby-Bauer method was used to evaluate the antimicrobial susceptibility of the nanofiber sheets using Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus). For the characterization of the nanofiber sheets incorporated with the drug, several techniques were used, such as Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), and scanning electron microscopy (SEM). Our results showed that the nanofiber sheets containing ceftriaxone had potential inhibitory activity against E. coli and S. aureus as they had inhibition zones of approximately 20–25 mm on Mueller-Hinton-agar-containing plates. In conclusion, our nanofiber sheets fabricated with ceftriaxone have potential inhibitory effects against bacteria and can be used as a dressing to treat wounds in hospitals and for other biomedical applications.

1,3,4-Oxadiazole Contained Sesquiterpene Derivatives: Synthesis and Microbiocidal Activity for Plant Disease

A series of 1,3,4-oxadiazole contained sesquiterpene derivatives were synthesized, and the activity of the target compounds against Xanthomonas oryzae pv. oryzae (Xoo), Xanthomonas axonopodis pv. citri (Xac), and tobacco mosaic virus (TMV) were evaluated. The biological activity results showed that the EC₅₀ values of compounds H4, H8, H11, H12, H14, H16, and H19 for Xac inhibitory activity were 33.3, 42.7, 56.1, 74.5, 37.8, 43.8, and 38.4 μg/ml, respectively. Compounds H4, H8, H15, H19, H22, and H23 had inhibitory effects on Xoo, with EC₅₀ values of 51.0, 43.3, 43.4, 50.5, 74.6, and 51.4 μg/ml, respectively. In particular, the curative and protective activities of compound H8 against Xoo in vivo were 51.9 and 49.3%, respectively. In addition, the EC₅₀ values of the inactivation activity of compounds H4, H5, H9, H10, and H16 against TMV were 69.6, 58.9, 69.4, 43.9, and 60.5 μg/ml, respectively. The results of molecular docking indicated that compound H10 exhibited a strong affinity for TMV-coat protein, with a binding energy of −8.88 kcal/mol. It may inhibit the self-assembly and replication of TMV particles and have an anti-TMV effect, which supports its potential usefulness as an antiviral agent.

Synthesis of polyacrylonitrile/polytetrahydropyrimidine (PAN/PTHP) nanofibers with enhanced antibacterial and anti-viral activities for personal protective equipment

Emerging infectious diseases caused by the spread of bacteria and viruses are a major burden on global economic development and public health. At present, most personal protective equipment has weak antibacterial and anti-viral properties. The PAN/PTHP nanofibers reported in this article provide a new method for the development of personal protective equipment. In this study, a mixture of PTHP and PAN was prepared into PAN/PTHP nanofibers with high-efficiency and long-lasting antibacterial effects (>99.999%) through the electrospinning process. Live/dead staining and cell proliferation experiments showed that the preparation of PAN/PTHP nanofibers has good cell compatibility. In addition, PAN/PTHP nanofibers show obvious destructive effects on lentiviruses. Based on these characteristics, PAN/PTHP nanofibers were applied to facial masks, which can be used as the inflatable biocidal layer of facial masks and have an excellent interception effect on particles in the air. The successful synthesis of these fascinating materials may provide new insights for the development of new protective materials.

Synthesis and Antifungal and Insecticidal Activities of Novel N-Phenylbenzamide Derivatives Bearing a Trifluoromethylpyrimidine Moiety

Seventeen novel N-phenylbenzamide derivatives bearing a trifluoromethylpyrimidine moiety were synthesized via four-step reactions. Their antifungal and insecticidal properties were evaluated. Antifungal test results demonstrated that some of the synthesized compounds showed better in vitro bioactivities against Phomopsis sp., Botryosphaeria dothidea (B. dothidea), and Botrytis cinerea (B. cinerea) at 50 μg/mL than pyrimethanil. Unfortunately, the synthesized compounds revealed lower insecticidal activities against Spodoptera frugiperda (S. frugiperda) and Mythimna separata (M. separata) at 500 μg/mL than chlorantraniliprole.

New 1,2,3-Triazole Scaffold Schiff Bases as Potential Anti-COVID-19: Design, Synthesis, DFT-Molecular Docking, and Cytotoxicity Aspects

Schiff bases encompassing a 1,2,3-triazole motif were synthesized using an efficient multi-step synthesis. The formations of targeted Schiff base ligands were confirmed by different spectroscopic techniques (FT-IR, ¹H NMR, ¹³C NMR, and CHN analysis). The spectral data analysis revealed that the newly designed hydrazones exist as a mixture of trans-E and cis-E diastereomers. Densityfunctional theory calculations (DFT) for the Schiff bases showed that the trans-trans form has the lowest energy structure with maximum stability compared to the other possible geometrical isomers that could be present due to the orientation of the amidic NH-C=O group. The energy differences between the trans-trans on one side and syn-syn and syn-trans isomers on the other side were 9.26 and 5.56 kcal/mol, respectively. A quantitative structure-activity relationship investigation was also performed in terms of density functional theory. The binding affinities of the newly synthesized bases are, maybe, attributed to the presence of hydrogen bonds together with many hydrophobic interactions between the ligands and the active amino acid residue of the receptor. The superposition of the inhibitor N3 and an example ligand into the binding pocket of 7BQY is also presented. Further interesting comparative docking analyses were performed. Quantitative structure-activity relationship calculations are presented, illustrating possible inhibitory activity. Further computer-aided cytotoxicity analysis by Drug2Way and PASS online software was carried out for Schiff base ligands against various cancer cell lines. Overall, the results of this study suggest that these Schiff base derivatives may be considered for further investigation as possible therapeutic agents for COVID-19.

Synthesis and properties of sildenafil isostere

A series of novel pyrazolo[3,4-d]pyrimidin-4-one derivatives were synthesized and evaluated for their anti-phosphodiesterase-5 (PDE-5) activity. A total of 28 compounds, containing alkyl and aryl groups at the 1-N and 3-C positions on the pyrazole ring, and also bearing different alkyl substituents on the piperazine ring were synthesized. Four compounds (4d, 5d, 6d, and 5o) were found to have better inhibitory activity against PDE-5 (IC₅₀  < 10 nM). All four of the most active compounds contain a phenyl ring at the N1 position. Compounds containing a 3,5-dimethylpiperazinyl group show better activity than others. These results suggest that compound 5o can be used as a lead structure for developing new inhibitors of PDE-5.

Synthesis, biological evaluation of antioxidant-antibacterial activities and computational studies of novel anthracene- and pyrene-based Schiff base derivatives

Schiff base derivatives with anthracene- and pyrene-based units, A1-A6 and P1-P6 were synthesized (89%–99% yields). Schiff base derivatives were designed to possess an heterocyclic moiety on one side to enhance the coordination ability towards metals. To investigate the biological assay of the newly synthesized compounds, their DPPH (2,2-diphenyl-1-picrylhydrazyl) radical scavenging, metal chelating, reducing power, antibacterial and DNA binding activities were tested. A6 (63.1%) showed the maximum free radical scavenging activity among all. However, compound P3 at concentration of 200 μg/mL possessed the highest metal chelating (45.8%) activity and power of reduction. In addition, P3 and A6 showed antibacterial activity against all bacteria tested and both compounds were very well bound to CT-DNA. Density functional theory method with B3LYP/6-311++G(d,p) basis set was performed to get information about the structural and electronic properties of the present compounds. In addition, the metal coordination properties of the dimers of the parent Schiff bases were investigated through interactions with Zn²⁺.

Synthesis and Structural Characterization of (E)-4-[(2-Hydroxy-3-methoxybenzylidene)amino]butanoic Acid and Its Novel Cu(II) Complex

A novel Cu(II) complex based on the Schiff base obtained by the condensation of ortho-vanillin with gamma-aminobutyric acid was synthesized. The compounds are physico-chemically characterized by elemental analysis, HR-ESI-MS, FT-IR, and UV-Vis. The complex and the Schiff base ligand are further structurally identified by single crystal X-ray diffraction and 1H and 13C-NMR, respectively. The results suggest that the Schiff base are synthesized in excellent yield under mild reaction conditions in the presence of glacial acetic acid and the crystal structure of its Cu(II) complex reflects an one-dimensional polymeric compound. The molecular structure of the complex consists of a Cu(II) ion bound to two singly deprotonated Schiff base bridging ligands that form a CuN2O4 chelation environment, and a coordination sphere with a disordered octahedral geometry.

Design, Synthesis and Biological Evaluation of Novel 4-(4-Methoxynaphthalen-1-yl)-5-arylpyrimidin-2-amines as Tubulin Polymerization Inhibitors

A novel series of 4-(4-methoxynaphthalen-1-yl)-5-arylpyrimidin-2-amines were designed, synthesized, and evaluated for their anticancer activities. Most of the synthesized compounds exhibited moderate to high antiproliferative activity in comparison to the standard drug cisplatin. Among them, 5i bearing ethoxy at the 4-position of the phenyl was found to be the most active on MCF-7 and HepG2 cancer cell lines, with IC₅₀ values of 3.77 ± 0.36 and 3.83 ± 0.26 µM, respectively. Further mechanism study shown that 5i potently inhibited tubulin polymerization, induced cell cycle arrest at G2/M phase and cell apoptosis in MCF-7 cell line. Furthermore, molecular modeling study suggested that 5i probably binds to the colchicine site of tubulin.

Synthesis and Bioactivities Study of Novel Pyridylpyrazol Amide Derivatives Containing Pyrimidine Motifs

In this study, thirteen new pyridylpyrazolamide derivatives containing pyrimidine motifs were synthesized via six-step reactions. Bioassay results showed that some of the synthesized compounds revealed good antifungal properties against Sclerotinia sclerotiorum, Phytophthora infestans, Thanatephorus cucumeris, Gibberella zeae, Fusarium oxysporum, Cytospora mandshurica, Botryosphaeria dothidea, and Phompsis sp. at 50 μg/mL, which were similar to those of Kresoxim-methyl or Pyrimethanil. Meanwhile, bioassay results indicated that the synthesized compounds showed a certain insecticidal activity against Spodoptera litura, Mythimna separata, Pyrausta nubilalis, Tetranychus urticae, Rhopalosiphum maidis, and Nilaparvata lugens at 200 μg/mL, which was lower than that of Chlorantraniliprole. To the best of our knowledge, this study is the first report on the antifungal and insecticidal activities of pyridylpyrazol amide derivatives containing a pyrimidine moiety.

Design, Synthesis, and Bioactivity of α-Ketoamide Derivatives Bearing a Vanillin Skeleton for Crop Diseases

A series of novel α-ketoamide derivatives bearing a vanillin skeleton were designed and synthesized. Bioactivity tests on virus and bacteria were performed. The results indicated that some compounds exhibited excellent antitobacco mosaic virus (TMV) activities, such as compound 34 exhibited an inactivation activity of 90.1% and curative activity of 51.8% and compound 28 exhibited a curative activity of 54.8% at 500 μg mL^-1, which is equivalent to that of the commercial ningnanmycin (inactivation of 91.9% and curative of 51.9%). Moreover, the in vitro antibacterial activity test illustrated that compounds 2, 22, and 33 showed much higher activities than commercial thiodiazole copper, which could be used as lead compounds or potential candidates. The findings of transmission electron microscopy and molecular docking indicated that the synthesized compounds exhibited strong and significant binding affinity to the TMV coat protein and could obstruct the self-assembly and increment of TMV particles. This study revealed that α-ketoamide derivatives bearing a vanillin skeleton could be used as a novel potential pesticide for controlling the plant diseases.

Crystal structure of 4-((2-methyl-6-(trifluoromethyl)pyrimidin-4-yl)oxy)benzoic acid, C13H9F3N2O3

C13H9F3N2O3, monoclinic, P21/c (no. 14), a = 8.6952(7) Å, b = 19.6715(18) Å, c = 8.0995(8) Å, β = 110.691(3)°, V = 1296.0(2) Å3, Z = 4, R gt(F) = 0.0558, wR ref(F 2) = 0.1358, T = 298(2) K.

4-(3-Phenyl-1H-pyrazolo[3,4-d]pyrimidin-1-yl)thieno[3,2-d]pyrimidine

A new hybrid compound, 4-(3-phenyl-1H-pyrazolo[3,4-d]pyrimidin-1-yl)thieno[3,2-d]pyrimidine 3, with promising biological activity was efficiently synthesized by the reaction of 3-phenyl-1-(thieno[3,2-d]pyrimidin-4-yl)-1H-pyrazol-5-amine with Vilsmeier–Haack reagent and subsequent treatment with ammonium carbonate. The structure of the synthesized compound was fully characterized by 1H-, 13C-NMR, IR spectroscopy, mass-spectrometry and elemental analysis.

Design, Synthesis, and Antiviral Activities of Coumarin Derivatives Containing Dithioacetal Structures

In this study, a series of coumarin derivatives containing dithioacetals were synthesized, characterized, and assessed for their anti-tobacco mosaic virus (TMV) activities. Biological tests showed that most of the title compounds exhibited significant anti-TMV biological activities; in particular, compound b21 showed good inactivating activity anti-TMV, with an EC₅₀ of 54.2 mg/L, superior to that of ribavirin (134.2 mg/L). Transmission electron microscopy analyses showed that compound 21 severely ruptured TMV particles. The interaction of compound b21 with TMV coat protein (TMV CP) was investigated using microscale thermophoresis and molecular docking. Compound b21 exhibited a strong binding ability to TMV CP, with a value of 2.9 μM, superior to ribavirin.