Luminescent Enhancement of Heterostructure Organic Light-Emitting Devices Based on Aluminum Quinolines

High performance organic light-emitting devices （OLEDs） have been investigated by using fluorescent bis （2-methyl-8-quinolinolato）（para-phenylphenolato）aluminum（BAlq） as an emissive layer on the performance of multicolor devices consisting of N, N＇-bis-（1-naphthyl）-N,N＇diphenyl- 1,1＇-biphenyl-4,4＇- diamine （NPB） as hole transport layer. The results show that the performance of heterostructure blue light-emitting device composed of 8-hydroxyquinoline aluminum （Alq3） as an electron transport layer has been dramatically enhanced. In the case of high performance heterostructure devices, the electroluminescent spectra has been perceived to vary strongly with the thickness of the organic layers due to the different recombination region, which indicates that various color devices composed of identical components could be implemented by changing the film thickness of different functional layers.

A CONVENIENT SYNTHESIS OF FLUORINE-CONTAINING QUINOLINES

2-Fluoroalkyl-4-hydroxy-quinolines were easily obtained from the reactions of 2-(F-alkyl)acetates with aromatic amines in the presence of Et_3N,followed by cyclization of the intermediates with PPA.

Unsupported nanoporous palladium‐catalyzed chemoselective hydrogenation of quinolines:Heterolytic cleavage of H_2 molecule

An efficient and highly chemoselective heterogeneous catalyst system for quinoline hydrogenation was developed using unsupported nanoporous palladium(PdNPore).The PdNPore‐catalyzed chemoselective hydrogenation of quinoline proceeded smoothly under mild reaction conditions(low H2 pressure and temperature)to yield 1,2,3,4‐tetrahydroquinolines(py‐THQs)in satisfactory to excellent yields.Various synthetically useful functional groups,such as halogen,hydroxyl,formyl,ethoxycarbonyl,and aminocarbonyl groups,remained intact during the quinoline hydrogenation.No palladium was leached from PdNPore during the hydrogenation reaction.Moreover,the catalyst was easily recovered and reused without any loss of catalytic activity.The results of kinetic,deuterium‐hydrogen exchange,and deuterium‐labeling experiments indicated that the present hydrogenation involves heterolytic H2 splitting on the surface of the catalyst.

A Novel Green Synthesis of Quinolines through Acid-catalyzed Friedlander Reaction in Ionic Liquids

Quinoline derivatives were efficiently prepared through acid-catalyzed Friedlander reaction in ionic liquid ([bmim][BF4]). It is shown that the proposed method is operationally simple and environmentally benign in that the reaction media and the catalyst can be recovered and be reused effectively for at least four times.

Synthesis of polymer/CNTs composites for the heterogeneous asymmetric hydrogenation of quinolines

The development of heterogeneous catalytic processes is crucial for the synthesis of chiral compounds for both academic and industrial applications.However,thus far,such achievements have remained elusive.Herein,we report the heterogeneous asymmetric hydrogenation of 2-methylquinoline over solid chiral catalysts,which were prepared by the one-pot polymerization of(1R,2R)-N-(4-vinyl-benzenesulfonyl)-1,2-diphenylethane-1,2-diamine(VDPEN)and divinylbenzene(DVB)in the presence or absence of activated carbon(C)or carbon nanotubes(CNTs),followed by Ru coordination and anion exchange.The solid chiral catalysts were fully characterized by N2 sorption analysis,elemental analysis,TEM,FT-IR spectroscopy,and 13C CP-MAS NMR.All the solid chiral catalysts could efficiently catalyze the asymmetric hydrogenation of 2-methylquinoline to afford 2-methyl-1,2,3,4-tetrahydroquinoline with 90%ee.Studies have shown that polymer/C and polymer/CNTs composites are more active than pure polymers.The polymer/CNTs composite exhibited the highest activity among all the solid chiral catalysts under identical conditions,owing to the unique morphology of CNTs.The recycling stabilities of the solid chiral catalysts were greatly improved when ionic liquids(ILs)were employed as solvents;this is mainly attributed to the decreased leaching amount of anions owing to the confinement effect of ILs on ionic compounds.

Copper-catalyzed C(sp)-H aryl amination enables modular synthesis of quinolines and 2-quinolinones

Herein,we disclose a novel copper-catalyzed C(sp)-H aryl amination of terminal alkynes with anthranils,enabling the rapid generation of highly reactive secondary N-aryl ynamines for the modular synthesis of structurally diverse C2-substituted quinolines and 2-quinolinones.The in-situ formed carbonyl-ynamines are prone to tautomerize to carbonyl-ketenimines,which can efficiently react with a series of nucleophiles,including amines,alcohols,phenols,thiols,thiophenols,active-methylene compounds,and even water to produce various quinoline derivatives with the generation of H_(2)O as a sole and green byproduct.This method also unlocks a practical route to create various quinoline-fused heterocycles and can be successfully applied to the late-stage modification of complex molecules and the concise synthesis of bioactive targets.Mechanistic studies reveal a coppercatalyzed inner-sphere nitrene transfer process by using anthranils as novel aryl nitrene precursors.

C—F Bond Insertion into Indoles with CHBr_(2)F:An Efficient Method to Synthesize Fluorinated Quinolines and Quinolones

A mild and practical method for synthesizing fluorinated quinoline derivatives,which have a wide range of applications in pharmaceuticals,materials,and organic synthesis,was described through C—F bond insertion into indoles using CHBr_(2)F.The simple conditions,readily availability of CHBr_(2)F,as well as the versatility of the transformations make this strategy very powerful in synthesizing 3-fluoroquinoline and 3-fluoroquinolone.The mechanistic studies reveal that bromofluorocarbene generated in-situ under basic condition was the key intermediate.

Metal-free synthesis of quinolines by direct condensation of amides with alkynes: revelation of N-aryl nitrilium intermediates by 2D NMR techniques

Employing triflic anhydride/2-fluoropyridine as an activation system, the coupling reactions of secondary N-aryl amides with terminal alkynes yielded substituted quinolines in moderate to excellent yields. The reaction tolerated both electron-donating and electron-withdrawing groups at the benzamide moiety. Electron-rich aryl acetylenes served as excellent coupling partners, and aliphatic terminal alkynes such as cyclopropyl and conjugate vinyl acetylenes could also be used as reaction partners. By means of 2 D NMR techniques(heteronuclear multiple bond correlation(HMBC), heteronuclear single quantum correlation(HSQC)),nitrilium ions were probed as reactive intermediates which are in contrast with that suggested by Movassaghi on the basis of in situ IR monitoring experiments. On the basis of these results, a plausible mechanism for the formation of quinolines was suggested.

Nano-Fe_3O_4 encapsulated-silica particles bearing sulfonic acid groups as a magnetically separable catalyst for green and efficient synthesis of functionalized pyrimido[4,5-b]quinolines and indeno fused pyrido[2,3-d]pyrimidines in water

The magnetic nanoparticles supported silica sulfuric acid was used as an efficient catalyst for the synthesis of pyrimido[4,5-b]quinoIines and indeno fused pyrido（2,3-d]pyrimidines in water.The desired products were obtained in excellent yields.Fe_3O_4@SiO_2-SO_3H was readily recovered using an external magnet and could be reused several times without significant loss of reactivity.

Simple manganese carbonyl catalyzed hydrogenation of quinolines and imines

Manganese-catalyzed hydrogenation of unsaturated molecules has made tremendous progresses recently benefiting from non-innocent pincer or bidentate ligands for manganese.Herein,we describe the hydrogenation of quinolines and imines catalyzed by simple manganese carbonyls,Mn2(CO)10 or MnBr(CO)5,thus eliminating the prerequisite pincer-type or bidentate ligands.

Nickel oxide nanoparticles catalyzed synthesis of poly-substituted quinolines via Friedlander hetero-annulation reaction

Reusable acidic nickel oxide nanoparticles have been synthesized,characterized and applied as a catalyst to convert 2-aminoaryl ketones and β-ketoesters/ketones into the corresponding quinolines in good yields with high selectivity.This could serve as a simple and convenient procedure for the Friedlander annulations.

Hydrogen sulfide reduces oxidative stress in Huntington's disease via Nrf2

The pathophysiology of Huntington's disease involves high levels of the neurotoxin quinolinic acid. Quinolinic acid accumulation results in oxidative stress, which leads to neurotoxicity. However, the molecular and cellular mechanisms by which quinolinic acid contributes to Huntington's disease pathology remain unknown. In this study, we established in vitro and in vivo models of Huntington's disease by administering quinolinic acid to the PC12 neuronal cell line and the striatum of mice, respectively. We observed a decrease in the levels of hydrogen sulfide in both PC12 cells and mouse serum, which was accompanied by down-regulation of cystathionine β-synthase, an enzyme responsible for hydrogen sulfide production. However, treatment with NaHS(a hydrogen sulfide donor) increased hydrogen sulfide levels in the neurons and in mouse serum, as well as cystathionine β-synthase expression in the neurons and the mouse striatum, while also improving oxidative imbalance and mitochondrial dysfunction in PC12 cells and the mouse striatum. These beneficial effects correlated with upregulation of nuclear factor erythroid 2-related factor 2 expression. Finally, treatment with the nuclear factor erythroid 2-related factor 2inhibitor ML385 reversed the beneficial impact of exogenous hydrogen sulfide on quinolinic acid-induced oxidative stress. Taken together, our findings show that hydrogen sulfide reduces oxidative stress in Huntington's disease by activating nuclear factor erythroid 2-related factor 2,suggesting that hydrogen sulfide is a novel neuroprotective drug candidate for treating patients with Huntington's disease.

Microwave assisted synthesis of novel Hantzsch 1,4-dihydropyridines,acridine-1,8-diones and polyhydroquinolines bearing the tetrazolo[1,5-α]quinoline moiety and their antimicrobial activity assess

Microwave assisted efficient Hantzsch reaction via four-component coupling reactions of tetrazolo[1,5-α]quinoline-4-carbal-dehyde, dimedone/cyclohexane-1,3-dione,ethyl/methyl acetoacetate and ammonium acetate was described as the preparation of tetrazolo[1,5-α]quinoline based 1,4-dihydropyridines,acridine-1,8-diones and polyhydroquinolines.The process presented here is simple,rapid,environmentally welcoming and high yielding.All the derivatives were subjected to an in vitro antimicrobial screening against a representative panel of bacteria and fungi and results worth further investigations.

Synthesis of Furano[3,2-c]- and Pyrano[3,2-c]quinolines upon Imino Diels-Alder Reactions Initiated by Nitrosonium （NO^＋）

Efficient nitrosonium （NO＋）-initiated aza-Diels-Alder reactions of N-arylimines with 2,3-dihydrofuran or 3,4-dihydro-2H-pyran allowed access to furano[3,2-c]- or pyrano[3,2-c]quinolines. A mixture of cis and trans-quinoline isomers was obtained in various ratios and yields.

Synthesis of furo[3,2-c]- and pyrano[3,2-c]quinolines by lanthanide triflate catalyzed imino-Diels-Alder reaction

Imino Diels-Alder reaction of imines with 2,3-dihydrofuran or 3,4-dihydro-2H-pyran proceeded smoothly in the presence of a catalytic amount (0.5 mol %) of ytterbium triflate to afford furo[3,2-c]- and pyrano[3,2-c] quinolines conveniently in high yield.

Rare-Earth Metal Chlorides Catalyzed One-pot Syntheses of Quinolines under Solvent-free Microwave Irradiation Conditions

Under microwave irradiation and solvent-free conditions, rare-earth metal chlorides （RECl3） have been efficient catalysts for one-pot synthesis of quinoline derivatives to give products in good to excellent yields through the mul- ti-component reactions of aldehydes, amines, and alkynes. The rare-earth metal chlorides can be recycled for six times without notable loss of catalytic activities. This new synthetic approach has prominent features of a short re- action time, high yields of products, operational simplicity, broad substrate scopes, environmentally friendly prop- erty and commercially available catalysts. It extends the applications of rare-earth metal compounds as catalysts in organic synthesis.

Electrochemical synthesis of selenocyanated imidazo[1,5-a]quinolines under metal catalyst-and chemical oxidant-free conditions

Reported herein is the first example of electrochemical selenocyanation of imidazo[1,5-a]quinolines with KSeCN under metal catalyst-and chemical oxidant-free conditions.This sustainable strategy shows a broad scope and great compatibility with functional groups,and affords synthetically and biologically important selenocyanated imidazo[1,5-a]quinolines in good to excellent yields with cheap graphite and Ni plates as the electrodes.The gram-scale synthesis was also successfully conducted,which might demonstrate the potential value of this electrochemical protocol.

A Facile Synthesis of Benzo[h]quinolines via Silica-TsOH-P2O5 Promoted Condensation of 1-Naphthylamines with 1,3-Diketones under Solvent Free Conditions

A facile synthesis of benzo[h]quinolines has been developed via improved Combes reaction. A combination of silica gel, p-toluenesulfonic acid and phosphorus pentoxide was utilized to promote the condensation of 1-naphthylamines with 1,3-diketones under solvent free conditions. In this case, silica gel was used as reaction media, p-toluenesulfonic acid and phosphorus pentoxide were acted as catalyst and dehydrating agent, respectively.

N-methylation of quinolines with CO2 and H2 catalyzed by Ru-triphos complexes

N-methyl-tetrahydroquinolines(MTHQs) are a kind of very useful chemicals, which can be obtained from N-methylation of amines.However, the methylation of quinolines which is a kind of highly unsaturated nitrogen-containing heterocyclic aromatic compounds has not been reported. In this work, we report the first work for the synthesis of MTHQs by methylation of quinolines using CO_2 and H_2. It was found that Ru(acac)_3-triphos [triphos: 1,1,1-tris(diphenylphosphinomethyl)ethanl] complex was very active and selective for the N-methylation reaction of quinolines, and the yield of the desired product could reach 99%.

^(13)C NMR STRUCTURAL DETERMINATION OFALKYL QUINOLINES AND ASSIGNMENTOF THE SPECTRAL LINES

Four monoalkyl and two dialkyl quinolines have been synthesized.They are all new compounds. The structures of the compounds have been determined by 13C NMR method and the spectral lines have been assigned by combination of calculations based on empirical additive formulae, measurements of three bond coupling constants as well as interrelation of 1H and 13C NMR spectra.