Journal of Heterocyclic Chemistry最新文献

Coumarins are well known for their biological properties. A mild, efficient synthetic route is developed for biscoumarin compounds using ceric ammonium nitrate at room temperature. This method has broad substrate tolerance with 70%–97% isolated yield. The method also exemplified industrial utility as tested on a multigram scale, and particularly avoided column chromatography. Biscoumarin compounds prepared with diverse substitutions were screened for their quorum-quenching (QQ) potential to serve as potential alternatives to antibiotics against pathogenic bacteria. QQ activity of the prepared compounds was determined by their ability to inhibit violacein pigment production of bioreporter Chromobacterium violaceum in a concentration-dependent manner. Biscoumarins (1g, 1n, and 1d) showed impressive QQ activity on C. violaceum and also revealed very good antibiofilm activity against gram-negative ( Pseudomonas aeruginosa ATCC 27853 and Salmonella typhimurium ATCC 14028) and gram-positive ( Staphylococcus aureus ATCC 6538) human pathogens via the QQ mechanism, indicating their versatile nature against diverse QS signaling systems (AHL, HAQs, and agr). Moreover, molecular docking studies further confirmed our results with impressive binding affinity −8.7, −8.5, and −8.4 kcal/mol (1n, 1g, and 1d) to protein MvfR (PqsR) and binding affinity −9 kcal/mol to protein AgrA (transcription factor), both controlling the expression of virulence factors in P. aeruginosa and S. aureus , respectively. The present investigation highlights the potential of biscoumarin compounds in the medical field to treat life-threatening infections as an alternative to antibiotics.

A Cu(OTf)₂-catalyzed three-component reaction of arylamines, aromatic aldehydes, and functionalized phenylacetylenes has been successfully accomplished. This strategy provides a wide range of structurally diversified triphenylamine-tethered 2-arylquinoline derivatives in good yields with a variety of extended π-structures and functional group compatibility. The strategy described here is easily scalable and several useful synthetic transformations of the prepared functionalized 2-arylquinoline derivatives were also performed. Furthermore, the photophysical properties of the synthesized products were evaluated, exhibiting interesting fluorescence properties with large Stokes shifts.

A Cu(OTf)₂-catalyzed three-component reaction of arylamines, aromatic aldehydes, and functionalized phenylacetylenes has been successfully accomplished. This strategy provides a wide range of structurally diversified triphenylamine-tethered 2-arylquinoline derivatives in good yields with a variety of extended π-structures and functional group compatibility. The strategy described here is easily scalable and several useful synthetic transformations of the prepared functionalized 2-arylquinoline derivatives were also performed. Furthermore, the photophysical properties of the synthesized products were evaluated, exhibiting interesting fluorescence properties with large Stokes shifts.

An efficient 1,6-conjugate addition for the construction of C–N bonds from the reaction of para-Quinone methides (p-QMs) and the weak nucleophilic nitrogen atom of imides was reported. Studies have shown that trimethylamine (Et₃N) is an essential catalyst for ensuring the successful completion of this synthesis process. The reaction features a wide range of substrates, simple operation, good group tolerance, and high yields.

In the present work, a two novel series of spiro-selena[3,5,8]triazaacenaphthylene derivatives 3a-i and selena-3,5,8-triazaacenaphthylene-2-carbonitrile 5a-f were obtained via a simple and eco-friendly acid-catalyzed procedure through the condensation of selenopheno[2,3-b]pyridine 1 with alicyclic/aryl/heteroaryl ketones 2a-i and/or aryl methyl ketones 4a-f, respectively. The products were tested for antibacterial activity against four strains of bacteria ( Bacillus cereus (+G), Staphylococcus aureus (+G), Pseudomonas aeruginosa (−G), and Escherichia coli (−G)), with Ciprofloxacin serving as a reference drug, demonstrating strong activity, especially for spiro-derivative 3f and triazaacenaphthylene 5f. Furthermore, DPPH antioxidant studies with vitamin C as a positive control were performed, indicating that spiro-derivative 3d and triazaacenaphthylene 5a had significantly higher redox activity (52% scavenging) compared to ascorbic acid (74%).

Bacterial diseases have been devastating plant pathogens to crops. However, there are few efficient agents to control them. Thus, it is crucial to find novel agents to protect crops from pathogenic bacteria. Here, we designed and synthesized a total of 24 novel indole derivatives containing a [1,2,4]triazole moiety, and their structures were characterized by ¹H, ¹³C NMR, and high-resolution mass spectrometry. Antibacterial activity revealed compound J (EC₅₀ = 4.31 ± 0.26 μg/mL) exhibited excellent activity in vitro against Xanthomonas oryzae pv. oryzae (Xoo) compared with the positive agent bismerthiazol (EC₅₀ = 40.23 ± 1.20 μg/mL) and thiodiazole-copper (EC₅₀ = 34.85 ± 1.72 μg/mL). J (control efficiency was 56.96%) also showed good protective activity in vivo against Xoo compared with the positive agent 1-phenazinecarboxylic acid (control efficiency was 37.01%). The preliminary mechanism showed J can inhibit Xoo through activating the ROS production, interfering with extracellular polysaccharide production, and biofilm formation of bacteria. On the other hand, J can increase the plant immunity reactions to hamper Xoo spread in the rice plant. The molecular docking of the most active compound J indicated excellent binding potential with its respective targets. These results demonstrated that J had a promising perspective and development as a potential antibacterial lead structure and agent in the future.

Bacterial diseases have been devastating plant pathogens to crops. However, there are few efficient agents to control them. Thus, it is crucial to find novel agents to protect crops from pathogenic bacteria. Here, we designed and synthesized a total of 24 novel indole derivatives containing a [1,2,4]triazole moiety, and their structures were characterized by ¹H, ¹³C NMR, and high-resolution mass spectrometry. Antibacterial activity revealed compound J (EC₅₀ = 4.31 ± 0.26 μg/mL) exhibited excellent activity in vitro against Xanthomonas oryzae pv. oryzae (Xoo) compared with the positive agent bismerthiazol (EC₅₀ = 40.23 ± 1.20 μg/mL) and thiodiazole-copper (EC₅₀ = 34.85 ± 1.72 μg/mL). J (control efficiency was 56.96%) also showed good protective activity in vivo against Xoo compared with the positive agent 1-phenazinecarboxylic acid (control efficiency was 37.01%). The preliminary mechanism showed J can inhibit Xoo through activating the ROS production, interfering with extracellular polysaccharide production, and biofilm formation of bacteria. On the other hand, J can increase the plant immunity reactions to hamper Xoo spread in the rice plant. The molecular docking of the most active compound J indicated excellent binding potential with its respective targets. These results demonstrated that J had a promising perspective and development as a potential antibacterial lead structure and agent in the future.

An efficient, eco-friendly one-pot synthesis of 2-aryl quinazolinone derivatives through the dehydrogenative coupling of alcohols and 2-aminobenzonitriles in the presence of a Ni(II) catalyst. The catalytic protocol was eco-friendly, straightforward and provided the desired quinazolinone products with moderate to excellent yields (12 examples, yields ≤ 91%). The catalytic reaction was operated in low catalyst loading (5 mol%) water and hydrogen gas are the only by-products. The control experiments and mechanistic studies confirm that the reaction proceeds via an aldehyde and cyclic aminol intermediate. Additionally, large-scale synthesis of 2-(p-tolyl)quinazolin-4(3H)-one (72%) demonstrates the robustness of the present method.