A series of novel chalcone derivatives containing the 1,2,4-triazine moiety were synthesized and their structures were confirmed by 1H NMR, 13C NMR and elemental analyses. Antiviral bioassays revealed that most of the compounds exhibited good antiviral activity against tobacco mosaic virus (TMV) at a concentration of 500 μg mL−1. The designated compound 4l was 50% effective in terms of curative and protective activities against TMV with 50% effective concentrations (EC50) of 10.9 and 79.4 μg mL−1, which were better than those of ningnanmycin (81.4 and 82.2 μg mL−1). Microscale thermophoresis (MST) also showed that the binding of compound 4l to coat protein (TMV-CP) yielded a Kd value of 0.275 ± 0.160 μmol L−1, which was better than that of ningnanmycin (0.523 ± 0.250 μmol L−1). At the same time, molecular docking studies for 4l with TMV-CP (PDB code:1EI7) showed that the compound was embedded well in the pocket between the two subunits of TMV-CP. Meanwhile, compound 4a demonstrated excellent antibacterial activities against Ralstonia solanacearum (R. solanacearum), with an EC50 value of 0.1 μg mL−1, which was better than that of thiodiazole-copper (36.1 μg mL−1) and bismerthiazol (49.5 μg mL−1). The compounds act by causing folding and deformation of the bacterial cell membrane as observed using scanning electron microscopy (SEM). The chalcone derivatives thus synthesized could become potential alternative templates for novel antiviral and antibacterial agents.

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Novel chalcone derivatives containing a 1,2,4-triazine moiety: design, synthesis, antibacterial and antiviral activities

A series of novel myricetin derivatives containing a 1,2,4-triazole Schiff base were designed and synthesized. Their structures were systematically characterized using 1H NMR, 13C NMR, and HRMS. During antibacterial bioassays, 6f, 6i, and 6q demonstrated a good inhibitory effect against Xanthomonas axonopodis pv. citri (Xac), with half-maximal effective concentration (EC50) values of 10.0, 9.4, and 8.8 μg mL−1, respectively, which were better than those of bismerthiazol (54.9 μg mL−1) and thiodiazole copper (61.1 μg mL−1). Note that 6w demonstrated a good inhibitory effect against Ralstonia solanacearum (Rs) with and EC50 value of 15.5 μg mL−1, which was better than those of bismerthiazol (55.2 μg mL−1) and thiodiazole copper (127.9 μg mL−1). Similarly, 6a, 6d, and 6e demonstrated a good inhibitory effect against Xanthomonas oryzae pv. oryzae (Xoo) with EC50 values of 47.1, 61.2, and 61.0 μg mL−1, respectively, which were better than those of bismerthiazol (148.2 μg mL−1) and thiodiazole copper (175.5 μg mL−1). Furthermore, we used scanning electron microscopy (SEM) to study the possible sterilization process of the target compound 6q against Xac. The results indicated the possibility of destroying the bacterial cell membrane structure, resulting in an incomplete bacterial structure, and thus achieving inhibition. Furthermore, antiviral bioassays revealed that most compounds exhibited excellent antiviral activity against tobacco mosaic virus (TMV) at a concentration of 500 μg mL−1. The results of the molecular docking studies for 6g with TMV-CP (PDB code: 1EI7) showed that compound 6g had partially interacted with TMV-CP. Therefore, mechanistic studies of the action of compound 6g could be further studied based on that.

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Synthesis and antibacterial and antiviral activities of myricetin derivatives containing a 1,2,4-triazole Schiff base

A total of 22 quinazoline thioether derivatives incorporating a 1,2,4-triazolo[4,3-a]pyridine moiety were designed, synthesized, and evaluated as antimicrobial agents in agriculture. Among these co...

Synthesis, Crystal Structure, and Agricultural Antimicrobial Evaluation of Novel Quinazoline Thioether Derivatives Incorporating the 1,2,4-Triazolo[4,3-a]pyridine Moiety.

COVID-19, the disease caused by SARS-CoV-2, has been declared as a global pandemic. Traditional medicinal plants have long history to treat viral infections. Our in silico approach suggested that unique phytocompounds such as emodin, thymol and carvacrol, and artemisinin could physically bind SARS-CoV-2 spike glycoproteins (6VXX and 6VYB), SARS-CoV-2 B.1.351 South Africa variant of Spike glycoprotein (7NXA), and even with ACE2 and prevent the SARS-CoV-2 binding to the host ACE2, TMPRSS2 and neutrapilin-1 receptors. Since Chloroquine has been looked as potential therapy against COVID-19, we also compared the binding of chloroquine and artemisinin for its interaction with spike proteins (6VXX, 6VYB) and its variant 7NXA, respectively. Molecular docking study of phytocompounds and SARS-CoV-2 spike protein was performed by using AutoDock/Vina software. Molecular dynamics (MD) simulation was performed for 50ns. Among all the phytocompounds, molecular docking studies revealed lowest binding energy of artemisinin with 6VXX and 6VYB, with Etotal −10.5 KJ mol−1 and −10.3 KJ mol−1 respectively. Emodin showed the best binding affinity with 6VYB with Etotal −8.8 KJ mol−1and SARS-CoV-2 B.1.351 variant (7NXA) with binding energy of −6.4KJ mol−1. Emodin showed best interactions with TMPRSS 2 and ACE2 with Etotal of −7.1 and −7.3 KJ mol−1 respectively, whereas artemisinin interacts with TMPRSS 2 and ACE2 with Etotal of −6.9 and −7.4 KJ mol−1 respectively. All the phytocompounds were non-toxic and non-carcinogenic. MD simulation showed that artemisinin has more stable interaction with 6VYB as compared to 6VXX, and hence proposed as potential phytochemical to prevent SARS-CoV-2 interaction with ACE-2 receptor.

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Phytocompounds of Rheum emodi , Thymus serpyllum , and Artemisia annua Inhibit Spike Protein of SARS-CoV-2 Binding to ACE2 Receptor: In Silico Approach.

The pyrazole-4-carboxamide scaffold containing a flexible amide chain has emerged as the molecular skeleton of highly efficient agricultural fungicides targeting succinate dehydrogenase (SDH). Based on the above vital structural features of succinate dehydrogenase inhibitors (SDHI), three types of novel pyrazole-4-formylhydrazine derivatives bearing a diphenyl ether moiety were rationally conceived under the guidance of a virtual docking comparison between bioactive molecules and SDH. Consistent with the virtual verification results of a molecular docking comparison, the in vitro antifungal bioassays indicated that the skeleton structure of title compounds should be optimized as an N'-(4-phenoxyphenyl)-1H-pyrazole-4-carbohydrazide scaffold. Strikingly, N'-(4-phenoxyphenyl)-1H-pyrazole-4-carbohydrazide derivatives 11o against Rhizoctonia solani, 11m against Fusarium graminearum, and 11g against Botrytis cinerea exhibited excellent antifungal effects, with corresponding EC50 values of 0.14, 0.27, and 0.52 μg/mL, which were obviously better than carbendazim against R. solani (0.34 μg/mL) and F. graminearum (0.57 μg/mL) as well as penthiopyrad against B. cinerea (0.83 μg/mL). The relative studies on an in vivo bioassay against R. solani, bioactive evaluation against SDH, and molecular docking were further explored to ascertain the practical value of compound 11o as a potential fungicide targeting SDH. The present work provided a non-negligible complement for the structural optimization of antifungal leads targeting SDH.

Expedient Discovery for Novel Antifungal Leads Targeting Succinate Dehydrogenase: Pyrazole-4-formylhydrazide Derivatives Bearing a Diphenyl Ether Fragment.

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

A series of novel anthranilic diamide derivatives (5a–5ab) containing moieties of trifluoromethylpyridine and hydrazone was designed and synthesized. The synthesized compounds were evaluated in viv...

Synthesis of Anthranilic Diamide Derivatives Containing Moieties of Trifluoromethylpyridine and Hydrazone as Potential Anti-Viral Agents for Plants.

The diacylhydrazine derivatives have attracted considerable attention in recently years due to their simple structure, low toxicity, and high insecticidal selectivity. As well as 3-bromo-1-(3-chloropyridin-2-yl)-1H-pyrazole is an important scaffold in many insecticidal molecules. In an effort to discover new molecules with good insecticidal activity, a series of diacylhydrazine derivatives containing a 3-bromo-1-(3-chloropyridin-2-yl)-1H-pyrazole scaffold was synthesized and bio-assayed. Bioassays demonstrated that some of the title compounds exhibited favorable insecticidal activities against Helicoverpa armigera and Plutella xylostella. The insecticidal activity of compounds 10g, 10h, and 10w against H. armigera were 70.8, 87.5, and 79.2%, respectively. Compounds 10c, 10e, 10g, 10h, 10i, 10j and 10w showed good larvicidal activity against P. xylostella. In particular, the LC50 values of compounds 10g, 10h, and 10w were 27.49, 23.67, and 28.90 mg L−1, respectively. A series of diacylhydrazine derivatives containing a 3-bromo-1-(3-chloropyridin-2-yl)-1H-pyrazole scaffold was synthesized and bio-assayed. The results of insecticidal tests revealed that the synthesized diacylhydrazine derivatives possessed weak to good insecticidal activities against H. armigera and P. xylostella. Compounds 10g, 10h, and 10x showed much higher insecticidal activity than tebufenozide, and exhibited considerable prospects for further optimization. Primary structure–activity relationship revealed that phenyl, 4-fluoro phenyl and four fluorophenyl showed positive influence on their insecticidal activities, and introduction of a heterocyclic ring (pyridine and pyrazole) showed negative impacts on their insecticidal effects.

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Synthesis and insecticidal activity of diacylhydrazine derivatives containing a 3-bromo-1-(3-chloropyridin-2-yl)-1H-pyrazole scaffold.

Novel acylurea derivatives 7a-7ab were designed and synthesized by linking the active substructures trifluoromethylpyridine and anthranilic diamide via an acylurea bridge. Most of the title compounds exhibited good activity against tobacco mosaic virus (TMV), particularly compound 7x (EC50 of 211.8 μg/mL), which showed much higher curative activity than ningnanmycin (EC50 of 389.8 μg/mL), and compound 7ab, which showed excellent inactivation activity (EC50 of 36.1 μg/mL), similar to ningnanmycin (EC50 of 23.2 μg/mL). The preliminary mechanism of these derivatives was investigated. Autodocking analysis revealed that compounds 7x and 7ab had good affinity for TMV coat protein (TMV CP), with low binding energies (-7.86 and -8.59 kcal/mol) comparable to ningnanmycin (-8.75 kcal/mol). Molecular dynamics simulation showed that compound 7x had a stable system structure with a better binding free energy (-32.94 kcal/mol) than ningnanmycin (-25.62 kcal/mol). Microscale thermophoresis showed that compound 7x bound more strongly to TMV CP (Kd of 19.8 ± 7.3 μM) than ningnanmycin (Kd of 21.2 ± 7.3 μM). Transmission electron microscopy and self-assembly experiments demonstrated that compounds 7x and 7ab significantly obstructed the self-assembly of TMV RNA and TMV CP. This new acylurea derivative has excellent antiviral activity by targeting TMV CP and inhibiting TMV self-assembly and can be considered a candidate for antiviral applications.

Wang Yanyan

Papers

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

Synthesis of Anthranilic Diamide Derivatives Containing Moieties of Trifluoromethylpyridine and Hydrazone as Potential Anti-Viral Agents for Plants.

Synthesis and insecticidal activity of diacylhydrazine derivatives containing a 3-bromo-1-(3-chloropyridin-2-yl)-1H-pyrazole scaffold.

Design, Synthesis, and Mechanism of Antiviral Acylurea Derivatives Containing a Trifluoromethylpyridine Moiety.

Novel Trifluoromethyl Pyridine Derivatives Bearing a 1,3,4‐Oxadiazole Moiety as Potential Insecticide