Search Results (7)

Triazolopyrimidine sulfonamide herbicides, a prominent class of acetohydroxyacid synthase (AHAS) inhibitors, are exceptionally effective in controlling weeds in agricultural settings. To overcome metabolic resistance caused by the 5-demethylation of pyroxsulam, we sought to replace its 5-methoxy group on the triazolopyrimidine ring with alkyl substituents. This led to the synthesis of a series of N-(7-oxo-4,7-dihydro-[1,2,4]triazolo[1,5-a]pyrimidin-2-yl)arylsulfon-amides, which displayed significant structural diversification potential, culminating in the identification of the herbicidal hit compound I-20. However, the suboptimal lipophilicity compromised its herbicidal efficacy. To rectify this limitation, we modified the 7-carbonyl group to a tert-butoxy group, resulting in the highly active compound I-29. This compound demonstrated herbicidal activity comparable to or exceeding that of penoxsulam against various tested weeds, establishing it as a promising new lead compound and a candidate herbicide for further investigation. Subsequent studies revealed that I-29 exhibited a receptor binding mode and herbicidal activity profiles that closely aligned with those of penoxsulam. Moreover, its spatial structure was found to be even more conducive to inhibiting flavin adenine dinucleotide (FAD)-mediated AHAS activity. This research not only sheds light on addressing the challenge of 5-demethylation metabolic resistance in triazolopyrimidine sulfonamide herbicides but also offers new avenues for the development of AHAS-inhibiting triazolopyrimidine sulfonamide herbicides. Full article

Development of new sustainable pesticides represents a real challenge for researchers due to environmental issues and public health aspects. In fact, the overuse of chemical pesticides has led to environmental damage, loss of biodiversity, and pesticide-resistant pests. In a framework characterized by the necessity of new sustainable agricultural practices, this study investigates the plant Genista ulicina as a producer of bioactive compounds for potential application as eco-friendly biopesticides. First, both roots and aerial parts of G. ulicina were extracted and the main compounds in the crude extracts were identified via GC-MS. Subsequently, the crude extracts were submitted to antifungal and phytotoxic assays. In particular, the antifungal effects were evaluated on three common phytopathogenic fungi, Fusarium oxysporum, Alternaria alternata, and Botrytis cinerea, while phytotoxic activity was evaluated on two weed species: Euphorbia peplus L. and Oxalis corniculata L. Further insights were obtained on the herbicidal potential of phytochemical compounds produced by G. ulicina through in silico investigations. In particular, molecular docking analyses were performed against three key enzymes involved in essential plant metabolic pathways: acetohydroxyacid synthase (AHAS), 4-hydroxyphenylpyruvate dioxygenase (HPPD), and protoporphyrinogen oxidase (PPO). Among the compounds identified, linolelaidic acid methyl ester, 1-monolinolein, stearic acid, and palmitic acid derivatives showed promising binding affinities and favorable interaction patterns compared to reference ligands. Selected phytochemicals from G. ulicina show potential as inhibitors of key herbicide targets, suggesting their value as promising leads in the development of sustainable bio-based weed control agents. Full article

Methicillin-resistant Staphylococcus aureus (MRSA) is a worldwide health threat and has already tormented humanity during its long history, creating an urgent need for the development of new classes of antibacterial agents. In this study, twenty-one novel sulfonylurea derivatives containing phenyl-5-vinyl and pyrimidinyl-4-aryl moieties were designed and synthesized, among which, nine compounds exhibited inhibitory potencies against Gram-positive bacterial strains: MRSA (Chaoyang clinical isolates), S. aureus ATCC6538, vancomycin-resistant Enterococci-309 (VRE-309), and Bacillus subtilis ATCC 6633. Especially, 9i and 9q demonstrated inhibitory activities against the four bacterial strains with minimum inhibitory concentrations (MICs) of 0.78–1.56 μg/mL, and quite a few of other MRSA clinical strains with MICs of 0.78 μg/mL, superior to those of the positive controls vancomycin (MIC of 1 μg/mL) and methicillin (MIC of >200 μg/mL). This is the very first time that sulfonylurea derivatives have been identified as promising inhibitors against different MRSA clinical isolates. In addition, all the MIC values of the synthesized compounds against Candida albicans were greater than 100 μg/mL. Since the reported anti-Candida activities of sulfonylureas were due to acetohydroxyacid synthase (AHAS) inhibition, the molecular target against MRSA for the target sulfonylureas was thought to be a different mode of action. Density functional theory (DFT) calculations were finally performed to understand the structure–activity relationships, based on which, significant differences were observed between their HOMO maps for compounds with strong antibacterial activities and weak anti-MRSA effects. The present results hence provide valuable guidance for the discovery of novel agents to treat bacterial infections, especially against MRSA. Full article

Several 2-substituted (H, Ph, and S-Me) and 1-substituted (H, Ph, and Bn), 3-hydroxy-1,3-quinazolin(di)ones were utilized for the first time as radical trapping agents in asymmetric 1,2-oxytrifluoromethylation of styrenes catalyzed by chiral vanadyl methoxide complexes bearing 3,5-disubstituted-N-salicylidene-t-leucinate templates. The effects of catalysts and solvents on the asymmetric induction were systematically examined. The best and complementary scenarios involved the use of vanadyl complexes V(O)-1 and V(O)-2, which bear 3-(2,5-dimethyl)phenyl-5-bromophenyl and 3-t-butyl-5-bromophenyl groups in an i-propanol solvent at ambient temperature. The corresponding (R)-cross-coupling products by V(O)-1 were obtained in 45–71% (for 2-substituted series) and 59–93% yields (for 1-substituted series) for p-/m-methylstyrenes and m-halo/CF₃/CO₂Me-styrenes in 38–63% ees (the best in 2-H case) and 60–84% ees (the best in 1-benzyl cases), respectively. The corresponding (S)-cross-coupling products by V(O)-2 were obtained in 28–55% (for 2-substituted series) and 45–72% yields (for 1-substituted series) for the same substrate class in 50–91% ees (85–91% ees in 2-phenyl cases) and 64–75% ees (up to 74–75% ees for each 1-H, Ph, and Bn cases), respectively. Theoretical calculations were carried out to explain the origin and extent of enantiocontrols. They both may serve as potential inhibitors of acetohydroxyacid synthase and epidermal growth factor receptor (EGFR) kinases. Full article

The continuous, worldwide spread of multidrug-resistant (MDR) and extensively drug-resistant (XDR) tuberculosis (TB) endanger the World Health Organization’s (WHO) goal to end the global TB pandemic by the year 2035. During the past 50 years, very few new drugs have been approved by medical agencies to treat drug-resistant TB. Therefore, the development of novel antimycobacterial drug candidates to combat the threat of drug-resistant TB is urgent. In this work, we developed and optimized a total synthesis of the antimycobacterial natural flavonoid chlorflavonin by selective ruthenium(II)-catalyzed ortho-C(sp²)-H-hydroxylation of a substituted 3′-methoxyflavonoid skeleton. We extended our methodology to synthesize a small compound library of 14 structural analogs. The new analogs were tested for their antimycobacterial in vitro activity against Mycobacterium tuberculosis (Mtb) and their cytotoxicity against various human cell lines. The most promising new analog bromflavonin exhibited improved antimycobacterial in vitro activity against the virulent H37Rv strain of Mtb (Minimal Inhibitory Concentrations (MIC₉₀) = 0.78 μm). In addition, we determined the chemical and metabolic stability as well as the pK_a values of chlorflavonin and bromflavonin. Furthermore, we established a quantitative structure–activity relationship model using a thermodynamic integration approach. Our computations may be used for suggesting further structural changes to develop improved derivatives. Full article

Chickpea (Cicer arietinum L.) is an important crop in crop-rotation management in Israel. Imidazolinone herbicides have a wide spectrum of weed control, but chickpea plants are sensitive to acetohydroxyacid synthase (AHAS; also known as acetolactate synthase [ALS]) inhibitors. Using the chemical mutagen ethyl methanesulfonate (EMS), we developed a chickpea line (M2033) that is resistant to imidazolinone herbicides. A point mutation was detected in one of the two genes encoding the AHAS catalytic subunit of M2033. The transition of threonine to isoleucine at position 192 (203 according to Arabidopsis) conferred resistance of M2033 to imidazolinones, but not to other groups of AHAS inhibitors. The role of this substitution in the resistance of line M2033 was proven by genetic transformation of tobacco plants. This resistance showed a single-gene semidominant inheritance pattern. Conclusion: A novel mutation, T192I (T203I according to Arabidopsis), providing resistance to IMI herbicides but not to other groups of AHAS inhibitors, is described in the AHAS1 protein of EMS-mutagenized chickpea line M2033. Full article

Background: The spread of herbicide-resistance Ambrosia artemisiifolia threatens not only the production of agricultural crops, but also the composition of weed communities. The reduction of their spread would positively affect the biodiversity and beneficial weed communities in the arable habitats. Detection of resistant populations would help to reduce herbicide exposure which may contribute to the development of sustainable agroecosystems. Methods: This study focuses on the application of target-site resistance (TSR) diagnostic of A. artemisiifolia caused by different herbicides. We used targeted amplicon sequencing (TAS) on Illumina Miseq platform to detect amino acid changes in herbicide target enzymes of resistant and wild-type plants. Results: 16 mutation points of four enzymes targeted by four herbicide groups, such as Photosystem II (PSII), Acetohydroxyacid synthase (AHAS), 5-enolpyruvylshikimate 3-phosphate synthase (EPSPS) and protoporphyrinogen IX oxidase (PPO) inhibitors have been identified in common ragweed populations, so far. All the 16 mutation points were analyzed and identified. Out of these, two mutations were detected in resistant biotypes. Conclusions: The applied next-generation sequencing-targeted amplicon sequencing (NGS-TAS) method on A. artemisiifolia resistant and wild-type populations enable TSR detection of large sample numbers in a single reaction. The NGS-TAS provides information about the evolved herbicide resistance that supports the integrated weed control through the reduction of herbicide exposure which may preserve ecological properties in agroecosystems. Full article