Design, Synthesis, and Bioactivity of Chalcone Derivatives Containing Indanone

Transition metal-catalyzed transformations of 2-formylarylboronic acids

2-Formylarylboronic acids are easily available precursors in organic chemistry. Different types of transition metal catalysts, such as Pd(0), Pd(II), Rh(I), Ir(I), Ni(II), Cu(I), Cu(II), and Co(II), can efficiently catalyze coupling reactions of 2-formylarylboronic acids with other organic reactants. In this review, we describe the synthesis of a diverse range of carbocyclic and heterocyclic compounds, as well as acyclic compounds, via transition metal-catalyzed reactions of 2-formylarylboronic acids over the past two decades.

Synthesis and Antifungal Activity of Chalcone Derivatives Containing 1,3,4-Thiadiazole

24 chalcone derivatives containing 1,3,4-thiadiazole were synthesized. The results of bioactivity tests indicated that some of the target compounds exhibited superior antifungal activities in vitro. Notably, the EC50 value of D4 was 14.4 μg/mL against Phomopsis sp, which was significantly better than that of azoxystrobin (32.2 μg/mL) and fluopyram (54.2 μg/mL). The in vivo protective activity of D4 against Phomopsis sp on kiwifruit (71.2 %) was significantly superior to azoxystrobin (62.8 %) at 200 μg/mL. The in vivo protective activities of D4 were 74.4 and 57.6 % against Rhizoctonia solani on rice leaf sheaths and rice leaves, respectively, which were slightly better than those of azoxystrobin (72.1 and 49.2 %) at 200 μg/mL. Scanning electron microscopy (SEM) results showed that the mycelial surface collapsed, contracted and grew abnormally after D4 treatment. Finally, the results were further verified by in vivo antifungal assay, fluorescence microscopy (FM) observation, determination of relative conductivity, membrane lipid peroxidation degree assay, and determination of cytoplasmic content leakage. Molecular docking results suggested that D4 could be a potential SDHI.

Design, synthesis and antiviral activity of indole derivatives containing quinoline moiety

A series of indole derivatives containing quinoline structures were designed and synthesized. The synthesized compounds were characterized by NMR and HRMS. And W14 was performed by single crystal X-ray diffraction experiments. The antiviral activity studies showed that some of the target compounds possessed significant activity against tobacco mosaic virus (TMV). In particular, W20 had significant activity. The results of in vivo anti-TMV activity assay showed that W20 possessed the best curative and protective activities with EC50 values of 84.4 and 65.7 μg/mL, which were better than ningnanmycin (NNM) 205.1 and 162.0 μg/mL, respectively. The results of Microscale thermophoresis (MST) showed that W20 had a strong binding affinity for the tobacco mosaic virus coat protein (TMV-CP) with a dissociation constant (Kd) of 0.00519 μmol/L, which was superior to that of NNM (1. 65320 μmol/L). The molecular docking studies were in accordance with the experimental results. In addition, the determination of malondialdehyde (MDA) content in tobacco leaves showed that W20 improved the disease resistance of tobacco. Overall, this study shows that indole derivatives containing quinoline can be used as new antiviral agents for plant viruses for further research.

Myricetin derivatives containing the benzoxazinone moiety discovered as potential anti-tobacco mosaic virus agents

A series of myricetin derivatives containing benzoxazinone were designed and synthesized. The structures of all compounds were characterized by NMR and HRMS. The structure of Y4 had been confirmed by single-crystal X-ray diffraction analysis. The test results of EC50 values of tobacco mosaic virus (TMV) suggested that Y8 had the best curative and protective effects, with EC50 values of 236.8, 206.0 μg/mL, respectively, which were higher than that of ningnanmycin (372.4, 360.6 μg/mL). Microscale thermophoresis (MST) experiments demonstrated that Y8 possessed a strong binding affinity for tobacco mosaic virus coat protein (TMV-CP), with a dissociation constant (Kd) value of 0.045 μM, which was superior to the ningnanmycin (0.700 μM). The findings of molecular docking studies revealed that Y8 interacted with multiple amino acid residues of TMV-CP through the formation of non-covalent bonds, which had an effect on the self-assembly of TMV particles. The malondialdehyde (MDA) and superoxide dismutase assay (SOD) content assays also fully verified that Y8 could stimulate the plant immune system and enhance disease resistance by reducing MDA content and increasing SOD content. In summary, myricetin derivatives containing benzoxazinone could be considered to further research and development as novel antiviral agents.

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 flavonol derivatives containing benzoxazole as potential antiviral agents: design, synthesis, and biological evaluation

A series of flavonol derivatives containing benzoxazole were designed and synthesized, and the structures of all the target compounds were determined by nuclear magnetic resonance (NMR) and high-resolution mass spectrometry (HRMS). The structure of X2 was further confirmed by single crystal X-ray diffraction analysis. The results of the bioactivity tests showed that some of the target compounds possessed excellent antiviral activity against tobacco mosaic virus (TMV) in vivo. In particular, the median effective concentration (EC50) values for the curative and protective activities of X17 against TMV were 127.6 and 101.2 μg/mL, respectively, which were superior to those of ningnanmycin (320.0 and 234.6 μg/mL). The results of preliminary mechanism study indicated that X17 had a strong binding affinity for TMV coat protein (TMV-CP), which might hinder the self-assembly and replication of TMV particles. In addition, X17 was able to effectively inhibit tobacco leaf membrane lipid peroxidation and facilitate the removal of O2- from the body, thereby improving the disease resistance of tobacco plants. Therefore, the design and synthesis of flavonol derivatives containing benzoxazole provides value for the development of new antiviral drugs.

Design, synthesis, and bioactivity studies of chalcone derivatives containing [1,2,4]-triazole-[4,3-a]-pyridine

In this study, 30 chalcone derivatives containing [1,2,4]-triazole-[4,3-a]-pyridine were designed and synthesized. The results of antibacterial activity showed that EC50 values of N26 against Xoo, Pcb was 36.41, 38.53 μg/mL, respectively, which were better than those of thiodiazole copper, whose EC50 values were 60.62, 106.75 μg/mL, respectively. The bacterial inhibitory activity of N26 against Xoo was verified by SEM. Antibacterial mechanism between N26 and Xoo was preliminarily explored, the experimental results showed that when the drug concentration was 100 mg/L, N26 had a good cell membrane permeability of Xoo, and it can inhibit the production of EPS content and extracellular enzyme content to disrupt the integrity of the Xoo biofilms achieving the effect of inhibiting Xoo. At 200 mg/L, N26 can protect and inhibit the lesions of post-harvested potatoes in vivo. The activities of N1-N30 against TMV were determined with half leaf dry spot method. The EC50 values of the curative and protective activity of N22 was 77.64 and 81.55 μg/mL, respectively, which were superior to those of NNM (294.27, 175.88 μg/mL, respectively). MST experiments demonstrated that N22 (Kd = 0.0076 ± 0.0007 μmol/L) had a stronger binding ability with TMV-CP, which was much higher than that of NNM (Kd = 0.7372 ± 0.2138 μmol/L). Molecular docking results showed that N22 had a significantly higher affinity with TMV-CP than NNM.

Synthesis of biofuel precursors from benzaldehyde and cyclopentanone via aldehyde-ketone condensation in a deep eutectic solvent system

Production of biofuel precursors from biomass-derived platform compounds (BDPC) has a profound influence on biofuel industries. Herein, an efficient catalytic system composed of the deep eutectic solvent (DES, i.e., ChCl/Fa) and SnCl4 (ChCl/Fa-SnCl4) was developed to produce biofuel precursors (C12 and C19) through aldehyde-ketone (A-K) condensation of benzaldehyde (BD) and cyclopentanone (CPO). ChCl/Fa-SnCl4 exhibited the prospective catalytic performance and given the high selectivity (SC12 = 49.20%, SC19 = 15.20%) and total yield (YC12+C19 = 64.37%) of C12 and C19, as well as 99.96% BD conversion under the optimized conditions (BD : CPO molar ratio of 1 : 6, ChCl : Fa molar ratio of 1 : 12, 4 mmol SnCl4, 80 °C for 120 min). Subsequently, the C12 and C19 precursors were successfully applied to generate cyclic alkanes (C12H14 and C19H18) by hydrodeoxygenation with selectivity of 37.61% and 24.10%, respectively. Finally, the potential catalytic mechanism was explored by density functional theory (DFT) calculations. The results unveiled that the formation of a stable structure for the ChCl/Fa-SnCl4 system was ascribed to the viable interactions among ChCl, Fa and SnCl4 by coordination bonds, electrostatic interactions and H-bonds, which decreased reaction energy barriers and drove the condensation of BD and CPO. In this case, the catalytic reactions between BD and CPO were enhanced to promote the synthesis of C12 and C19. This work provides a novel strategy for the applicability of different BDPC to synthesize fuel precursors for the development of liquid biofuels.