Synthesis, crystal structure, spectroscopic characterization and anti-fungal activity of Ethyl 2-Oxo-2H-chromene-3-carboxylateDerivatives

Novel Design of Pyrazolyl-Containing Monoterpene Compounds to Enhance Antifungal Efficacy Against Rhizoctonia solani

In the fields of agriculture and forestry, there are major unknown risks associated with the toxicity of chemical pesticide residues and pathogen resistance. To address this issue, in this study, 52 novel pyrazole monoterpene compounds were obtained by organic synthesis of highly active monoterpene natural products and evaluated for their in vitro and in vivo antifungal activities and crystal structure analysis of compound 5b. The results showed that compounds 4g and 8f exhibited remarkable antifungal activities against Rhizoctonia solani, with the corresponding EC50 values reaching 4.27 and 4.81 mg/L. At the same time, the results of in vivo and in vitro experiments showed that both compounds 4g and 8f had good control effects against rice sheath blight. The antifungal activity of these compounds was preliminarily explored by scanning electron microscopy, molecular docking, enzyme activity determination, and cytotoxicity, indicating that these compounds have the potential for development into low-toxic antifungal drugs.

Discovery of anti-phytopathogenic fungal activity of a new type of (S)-coumarin bearing a phenylpropanoid unit at the 3-position

The enantiospecific anti-phytopathogenic fungal activity of a new type of coumarin bearing a phenylpropanoid unit at the 3-position was found. (S)-3-[1-Methoxy-3-(4-methoxyphenyl)prop-2-yl]coumarin ((S)-5: EC50=16.5 µM) was 30 times more effective than the (R)-form against the Alternaria alternata Japanese pear pathotype. Derivatives bearing different substituents on the 7'-aromatic ring and the coumarin ring were synthesized to discover the more potent compounds. The 3'-CF3 and 4'-CF3 derivatives, 39 and 40, respectively, had the lowest EC50 values (1-2 µM) in this project, suggesting that the size of the electron-withdrawing and hydrophobic substituents at these positions gave an advantage. On the coumarin ring, the presence of the OCH3 or CH3 group at the 5-position accelerated the activity, as the (4'-OCH3, 5-OCH3) derivative 41 and (4'-OCH3, 5-CH3) derivative 45 were, respectively, 4-5 times more potent than the 4'-OCH3 derivative (S)-5.

Bidirectional "Win-Win": Asymmetrical Nanobowl-Coupled Aggregation-Induced Emissive Nanosilicon-Enhanced Immunochromatographic Strips for the Ultrasensitive Detection of Salmonella typhimurium

The lack of nanoprobes with an efficient signal response and overlook of cooperation between nanoprobes can be responsible for the unsatisfactory analytical performance of immunochromatographic strips (ITSs). Herein, asymmetrical nanobowl-confined innumerable gold nanoparticles (AuNPs) (AuNPs@AFRNBs) to enhance the light absorption are developed for quenching the fluorescence of aggregation-induced emissive (AIE) nanosilicons, which is used for the construction of a bidirectional complementary-enhanced ITS (BC-ITS) to ultrasensitively detect Salmonella typhimurium (S. typhimurium). Briefly, density functional theory-screened AIEgens with highly fluorescent brightness are confined in nanosilicons, and the nanoconfinement has improved the fluorescent brightness by 6.78-fold compared to the free AIEgens. Moreover, the substituent group effect has also enhanced the fluorescence of the prepared fluorescent nanosilicon by 10,000-fold in ITSs. By virtue of the superior light absorption of AuNPs@AFRNBs, the BC-ITS exhibits a bidirectional "win-win" performance for the sensitive monitoring of S. typhimurium: a "turn-on" mode with a high-brightness colorimetric response and an inverse "turn-off" fluorescence response, whose limits of detection are 364 and 302 CFU mL-1, respectively, which is approximately 100-fold more sensitive than the traditional AuNPs-ITS. Furthermore, the BC-ITS can be successfully used to identify S. typhimurium in milk, illustrating the superiority of the developed BC-ITS in point-of-care diagnosis.

Machine-Learning-Assisted Aggregation-Induced Emissive Nanosilicon-Based Sensor Array for Point-of-Care Identification of Multiple Foodborne Pathogens

How timely identification and determination of pathogen species in pathogen-contaminated foods are responsible for rapid and accurate treatments for food safety accidents. Herein, we synthesize four aggregation-induced emissive nanosilicons with different surface potentials and hydrophobicities by encapsulating four tetraphenylethylene derivatives differing in functional groups. The prepared nanosilicons are utilized as receptors to develop a nanosensor array according to their distinctive interactions with pathogens for the rapid and simultaneous discrimination of pathogens. By coupling with machine-learning algorithms, the proposed nanosensor array achieves high performance in identifying eight pathogens within 1 h with high overall accuracy (93.75-100%). Meanwhile, Cronobacter sakazakii and Listeria monocytogenes are taken as model bacteria for the quantitative evaluation of the developed nanosensor array, which can successfully distinguish the concentration of C. sakazakii and L. monocytogenes at more than 103 and 102 CFU mL-1, respectively, and their mixed samples at 105 CFU mL-1 through the artificial neural network. Moreover, eight pathogens at 1 × 104 CFU mL-1 in milk can be successfully identified by the developed nanosensor array, indicating its feasibility in monitoring food hazards.

Captopril supported on magnetic graphene nitride, a sustainable and green catalyst for one-pot multicomponent synthesis of 2-amino-4H-chromene and 1,2,3,6-tetrahydropyrimidine

Captopril (CAP) is a safe, cost-effective, and environmentally organic compound that can be used as an effective organo-catalyst. Functional groups of captopril make it capable to attach to solid support and acting as promoters in organic transformations. In this work, captopril was attached to the surface of magnetic graphene nitride by employing a linker agent. The synthesized composite efficiently catalyzed two multicomponent reactions including the synthesis of 1,2,3,6-tetrahydropyrimidine and 2-amino-4H-chromene derivatives. A large library of functional targeted products was synthesized in mild reaction conditions. More importantly, this catalyst was stable and magnetically recycled and reused for at least five runs without losing catalytic activity.

Synthesis, Crystal Structure, Spectral Characterization and Antifungal Activity of Novel Phenolic Acid Triazole Derivatives

At present, phenolic acid derivatives and triazole derivatives have a good antifungal effect, which has attracted widespread attention. A series of novel phenolic acid triazole derivatives were synthesized, and their structures were characterized by IR, MS, NMR, and X-ray crystal diffraction. Compound methyl 4-(2-bromoethoxy)benzoate, methyl 4-(2-(1H-1,2,4-triazol-1-yl) ethoxy)benzoate, 4-(2-(1H-1,2,4-triazol-1-yl)ethoxy)benzoic acid and 4-(2-(1H-1,2,4-triazol-1-yl) ethoxy)-3-methoxybenzoic acid crystallize in the monoclinic system with space group P21/n, the monoclinic system with space group P21, the monoclinic system with space group P21 and the orthorhombic system with space group Pca21, respectively. At a concentration of 100 μg/mL and 200 μg/mL, the antifungal activity against seven plant pathogen fungi was determined. Compound methyl 4-(2-bromoethoxy)benzoate has the best inhibitory effect on Rhizoctonia solani AG1, and the inhibitory rate reached 88.6% at 200 μg/mL. The inhibitory rates of compound methyl 4-(2-(1H-1,2,4-triazol-1-yl) ethoxy)benzoate against Fusarium moniliforme and Sphaeropsis sapinea at a concentration of 200 μg/mL were 76.1% and 75.4%, respectively, which were better than that of carbendazim.

Crystal structure of ethyl (Z)-3-amino-2-cyano-3-(2-oxo-2H-chromen-3-yl)acrylate, C15H12N2O4

C15H12N2O4, monoclinic, P21/c (no. 14), a = 5.4588(5) Å, b = 29.629(3) Å, c = 8.1217(8) Å, β = 93.157(1)°, V = 1311.6(2) Å3, Z = 4, R gt (F) = 0.0346, wR ref (F 2) = 0.0925, T = 296(2) K.

Crystal structure of 3-acetyl-6-hydroxy-2H-chromen-2-one monohydrate, C11H10O5

[C11H10O5], monoclinic, P21/n, a = 7.041(3) Å, b = 9.339(4) Å, c = 15.614(6) Å, β = 103.03°, V = 1000.2(7) Å3, Z = 4, Rgt (F) = 0.0337, wR ref (F 2) = 0.0994, T = 296(2) K.

Design, Synthesis and Bioactivity Evaluation of Coumarin-BMT Hybrids as New Acetylcholinesterase Inhibitors

Coumarin possesses the aromatic group and showed plentiful activities, such as antioxidant, preventing asthma and antisepsis. In addition, coumarin derivatives usually possess good solubility, low cytotoxicity and excellent cell permeability. In our study, we synthesized the compound bridge methylene tacrine (BMT), which has the classical pharmacophore structure of Tacrine (THA). Based on the principle of active substructure splicing, BMT was used as a lead compound and synthesized coumarin-BMT hybrids by introducing coumarin to BMT. In this work, 21 novel hybrids of BMT and coumarin were synthesized and evaluated for their inhibitory activity on AChE. All obtained compounds present preferable inhibition. Compound 8b was the most active compound, with the value of K_i as 49.2 nM, which was higher than Galantamine (GAL) and lower than THA. The result of molecular docking showed that the highest binding free energy was -40.43 kcal/mol for compound 8b, which was an identical trend with the calculated K_i.