10.1039/c3nj01308a
The research focuses on the synthesis, identification, and in vitro biological evaluation of novel quinoline-incorporated 1,3-thiazinan-4-one derivatives. The study describes the creation of two new series of compounds, (4a-j) and (5a-7j), through a one-pot three-component cyclo-condensation reaction, yielding products in moderate to good yields. The synthesis involved reactants such as 4-hydroxy-8-(trifluoromethyl)quinoline-3-carbohydrazide, substituted benzaldehydes, 3-mercaptopropionic acid, and 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide (EDC). The synthesized compounds were characterized using Fourier-transform infrared spectroscopy (FT-IR), proton and carbon-13 nuclear magnetic resonance (1H and 13C NMR), and elemental analysis to confirm their structures. The in vitro biological evaluation involved screening the compounds for antibacterial activity against both Gram-positive and Gram-negative bacteria, antitubercular activity against Mycobacterium Tuberculosis H37Rv, and antimalarial activity against Plasmodium falciparum. The results indicated that some compounds, particularly 4f and 5f, showed excellent antibacterial and antitubercular activity, while several others demonstrated good antimalarial activity, presenting potential as new antimicrobial, antitubercular, and antimalarial agents.
10.1002/aoc.3682
The research focuses on the development of a novel, green, and efficient catalytic system using zinc cation supported on λ-carrageenan magnetic nanoparticles (Zn2+/λ-carrageenan/Fe3O4) for the one-pot three-component synthesis of quinoline derivatives. The study involves the preparation of the catalyst through a series of steps, including the synthesis of nanomagnetite, coating it with λ-carrageenan, and decorating it with zinc cation. The catalyst's structure and properties were characterized using various techniques such as FT-IR spectroscopy, FE-SEM, EDX, TEM, XRD, VSM, TGA, and ICP analysis. The experiments involved a model reaction of benzaldehyde, aniline, and butanal, optimized for catalyst amount, solvent, and temperature, and then extended to a series of reactions with different substituted aldehydes and anilines. The analyses confirmed the successful synthesis of the catalyst and its high activity in the green synthesis of 16 quinoline derivatives with high yields, without the use of toxic solvents or co-catalysts.
10.1021/jo016196i
The study presents a novel method for synthesizing 2-chloroquinolines from 2-vinylanilines using diphosgene in acetonitrile as the solvent. The researchers detail a three-step reaction mechanism involving the generation of phenylisocyanate, quinoline ring formation, and chlorination at the C2 position of the quinoline. The purpose of the chemicals used in the study was to facilitate these steps, with diphosgene reacting with 2-vinylanilines to produce phenyl isocyanate, which then reacts with the acetonitrile to form the quinoline ring. The final step involves the chlorination of the C2 position. This new method eliminates the need for the hazardous use of excess phosphorus oxychloride, which was previously required in the synthesis of 2-chloroquinolines from 2(1H)-quinolinones. The study also discusses the role of acetonitrile as a reactive solvent in the process and provides evidence that the third step, chlorination, is likely the rate-determining step in the reaction.
10.1021/jm00096a018
The research focuses on the development of reversible inhibitors of the gastric (H+/K+)-ATPase, an enzyme crucial in gastric acid secretion. The purpose of this study was to explore the contribution of the quinoline 3-substituent to the activity of these inhibitors and to identify compounds that could potentially be used as therapies for acid-related gastrointestinal disorders. The researchers synthesized and tested a series of 3-substituted-4-(phenylamino)quinolines and concluded that a specific combination of properties, including electron withdrawal and hydrogen bonding by the 3-substituent, is necessary for high activity. They found that 3-acyl substituents, particularly butyryl and isobutyryl groups, provided an optimal combination of electronic properties, with compound 17c (SK&F 96067) emerging as a potent inhibitor of histamine-stimulated gastric acid secretion in animal models, leading to its selection for further development. The chemicals used in this process included various quinolines, substituted anilines, acyl chlorides, and other organic compounds, with the synthesis involving reactions such as acylation, cyclization, and displacement, among others.
10.1016/S0040-4020(01)81902-5
The study explores the efficient hydration of nitriles using the RuH2(PPh3)4 catalyst, converting them into corresponding amides under neutral conditions with only 1-2 equivalents of water. This method is advantageous due to its simplicity, high efficiency, and mild reaction conditions. The study extends this principle to transform ?-ketonitriles into ene-lactams, which are versatile intermediates for synthesizing piperidine and hydroquinoline ring systems. The efficiency of these reactions is demonstrated through the short-step synthesis of (-)-pumiliotoxin C, a toxic skin alkaloid produced by Central American frogs. The study also investigates the catalytic activities of various metal complexes in these transformations, finding RuH2(PPh3)4 to be the most effective. Additionally, the study explores the conversion of ene-lactams into ?-dioxylactams and further into ?-substituted lactams using different nucleophiles in the presence of TiCl4, providing a useful method for the stereoselective synthesis of cyclic amines.
10.1002/1522-2675(20011017)84:10<2895::AID-HLCA2895>3.0.CO;2-0
The research investigates the selective hydrogenation of quinoline to 1,2,3,4-tetrahydroquinoline using rhodium catalysts modified with the tripodal polyphosphine ligand MeC(CH?PPh?)?. The study aims to elucidate the catalytic mechanism and identify the electronic requirements of the metal catalyst for efficient hydrogenation, which is crucial for the hydrodenitrogenation of N-heterocycles in raw oil materials. Key chemicals include quinoline (Q), the rhodium catalyst precursors [Rh(DMAD)(triphos)PF?] (1) and [Rh(S(C?H?)CH=CH?-C?H?S)(triphos)] (2), and various intermediates and products such as [Rh(H)(triphos)]?, [Rh(Q-κN)?(triphos-xP)]? (6a-c), and [Rh(H)(Q-xN)(triphos-xP)]PF? (7). The study employs high-pressure NMR spectroscopy, kinetic studies, and isotope labeling to understand the reaction pathways. The findings show that the hydrogenation rate has an inverse concentration dependence on quinoline and that the presence of a Bronsted acid like triflic acid significantly enhances the catalytic activity. The proposed mechanism involves the coordination of quinoline to the rhodium center, oxidative addition of hydrogen, and subsequent bond-breaking steps. The study concludes that the selective hydrogenation of quinoline can be effectively achieved with the [Rh(H)(triphos)]? fragment, and the results provide insights into designing improved catalysts for hydrodenitrogenation processes.
10.1002/chem.201303341
The study investigates the DMSO-mediated ligand dissociation in N-heterocyclic-[Ru(h6-arene)Cl2] drug candidates, which are ruthenium-based organometallic complexes with potential anticancer and antiparasitic activities. The research focuses on the "piano-stool" complexes, so named due to their structural composition, and their tendency to dissociate when dissolved in dimethyl sulfoxide (DMSO), a common solvent used for preparing stock solutions in biological assays. The study used various ruthenium complexes with different N-heterocyclic ligands, such as benzimidazoles, imidazoles, pyridine, and quinoline derivatives, to understand the extent of ligand dissociation and its impact on the complexes' biological activity. The purpose of the study was to determine if the biological activity reported for these complexes could be influenced by the ligand dissociation occurring in DMSO, which could lead to a reconsideration of previous conclusions and potentially impact the development of new metal-based drugs. The study also explored the possibility of a "mix-and-screen" approach, where mixing [Ru(h6-arene)Cl2(DMSO)] complex with biologically active N-heterocyclic ligands could enhance the activity of certain potent ligands, offering a new strategy in drug discovery.
10.1016/j.bmcl.2013.02.100
The study explores the identification of potential analgesic compounds through virtual screening of large chemical databases. The researchers focused on disrupting the interaction between the PDZ protein PSD-95 and its target ligands, such as the glutamate NMDA receptor and the serotonin 5-HT2A receptor, to reduce hyperalgesia in neuropathic pain models. They virtually screened the Asinex and Cambridge databases, containing nearly one million molecules, using three successive docking filters and visual inspection. This process identified three structural classes of molecules: quinolines, N-acyl hydrazones, and carbohydrates derivatives linked to a phenyl group. The best ligand identified was quinoline 2, which was synthesized and evaluated for its binding ability with PSD-95 PDZ domains using 1H–15N HSQC NMR experiments. Quinoline 2 displayed promising binding ability and significant anti-hyperalgesic activity in a rat model of neuropathic pain, similar to the effect of a natural peptide ligand of PSD-95 PDZ domains.
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