51 |
New gas-phase cascade reactions of stabilising phosphorus ylides leading to ring-fused indoles and quinolinesMurray, Lorna January 2010 (has links)
Synthesis and flash vacuum pyrolysis (FVP) of stabilised phosphorus ylides containing an o-amino functionalised benzene ring has been examined for the first time. Model studies using N-methyl-N-tosyl and N-mesyl-N-methyl ylides showed that the ylides could be prepared, although yields were variable, and had the expected spectroscopic properties. Upon FVP, however, the expected loss of Ph₃PO and the sulfonyl group was accompanied by unexpected transfer of the reactive site from nitrogen to carbon giving 3- substituted quinolines rather than the expected indole products. Moving to ylides with an α-cinnamoyl group (or heterocyclic analogue) did, however, result in the originally planned tandem cyclisation leading to ring-fused carbazole products. N-Benzyl was also found to be a suitable thermally labile group and a series of α-cinnamoyl N-benzyl-N-methyl ylides were prepared and characterised. For their synthesis, use of N-cinnamoylbenzotriazoles was found to be preferable to cinnamoyl chloride, requiring only half the amount of amino-functionalised phosphonium salt. While FVP of some of these ylides led to benzo-, furo- and thienocarbazoles in good yield, others again gave quinoline-type products pointing to a fine balance between the two alternative modes of cyclisation. It was noted that one of the furocarbazole products was very similar to a natural product, Eustifoline D, isolated from the medicinally active shrub Murraya euchrestifolia from Taiwan and its synthesis was planned. With a view to producing the required N-H carbazole, N,N-dibenzylamino amino ylides were prepared and were found to exhibit restricted rotation leading to broad NMR signals. Their FVP again led to both quinoline and carbazole products, with the former having usually, but not always, lost a phenyl group. Mechanistic pathways for the formation of the various products are proposed. Complete assignment of the complex ¹H NMR spectra of the various fused-ring heterocyclic products was achieved, assisted by simulations in many cases. The ylide precursor required for Eustifoline D was prepared in five steps and 10% overall yield from 5-methylanthranilic acid. The final FVP step gave a quinoline as the major product, but the minor product was Eustifoline D, spectroscopically identical to the natural product.
|
52 |
Copolímeros emissores de luz contendo grupos fluoreno e quinolina: preparação, caracterização e montagem de LEDs. / Light emitting copolymers containing groups fluorene and quinoline: preparation, characterization and assembly of leds.Correia, Fábio Conte 13 July 2009 (has links)
Visando o crescente interesse em pesquisa de novos materiais para a fabricação de dispositivos eletrônicos a base de polímeros semicondutores, com elevado potencial para a fabricação de diodos emissores de luz poliméricos os (PLEDs - Polymer light-emitting diodes), este presente trabalho teve como objetivo a síntese de novos copolímeros através da reação de acoplamento de Suzuki e a sua fabricação de PLEDs com esses novos materiais. É conhecido que um dos grandes problemas na fabricação desses dispositivos é propiciar um maior número de recombinações elétrons/ lacunas no interior de suas camadas ativas com a finalidade de aumentar a emissão de luz visivel. Para amenizar esse problema os copolímeros sintetizados tiveram como finalidade unir num único material, a propriedade de transporte de elétrons associada à boa emissão de luz. O objetivo final foi elevar a injeção de elétrons contribuindo para aumentar o número de recombinações dos pares elétrons/lacunas, resultando em aumento de eletroluminescência e de eficiência dos dispositivos. Os copolímeros inéditos foram sintetizados e caracterizados por ressonância magnética nuclear hidrogênio, termogravimetria, calorimetria diferencial exploratória, espectroscopia no UV-Vis e no infravermelho, fluorimetria no UV-vis, cromatografia de permeação em gel e voltametria cíclica. Os copolímeros foram também utilizados como camada ativa na construção de uma série de PLEDs com arquiteturas diferentes, tanto puro como em mistura com o poli(N-vinilcarbazol) (PVK), ou, ainda, utilizando tris-8-hidroxiquinolina alumínio (Alq3) como camada transportadora de elétrons ( ETL - Electron transport layer). Os dispositivos foram caracterizados quanto ao comportamento elétrico, pelas curvas de corrente por tensão (IxV), e à sua eletroluminescência. Os PLEDS fabricados com os copolímeros sintetizados mostraram que não necessitam do uso de uma camada transportadora de elétrons, ETLs, adicional. / Polymer light-emitting diodes (PLEDs) have been heavily researched since their initial fabrication and utilization. In order to improve the efficiency of polymeric light-emitting devices, new materials have been studied. This present study focuses in the preparation of new copolymers by Suzuki coupling reaction and then evaluate the copolymers as active layer in PLEDs. It is well known that the performance of PLEDs is still limited by the number of electron/hole recombination. To overcome this problem, a new material is proposed to integrate the functions of n charge carrier and light emission through copolymerization. Novel copolymers were synthesized and characterized by hydrogen nuclear magnetic resonance, thermogravimetry, and differential scanning calorimetry, UVVis, Fluorescence and IR spectroscopy, GPC and cyclic voltammetry. Copolymers thus prepared were used as active layer in a series of PLEDs with different architectures, pure and in blends with poly(N-vinylcarbazole) (PVK), as well as with tris-8 hydroxyquinoline aluminum (Alq3) as an extra electron transport layer. The devices were characterized concerning their electrical behavior, by the characteristic J-V diode curves, and their electroluminescence. It was demonstrated that the PLEDs built with the synthesized copolymers do not need an extra ETL.
|
53 |
Síntese e caracterização de polímeros contendo 9,9-dioctilfluoreno e 8-oxioctilquinolina para utilização como camada emissora de PLEDs. / Synthesis and characterization of polymers containing 9,9-dioctylfluorene and 8-oxiloctylquinoline for layers in PLEDs.Correia, Fábio Conte 29 July 2013 (has links)
Utilizando a reação de acoplamento de Suzuki, novos polímeros e copolímeros semicondutores com elevado potencial para a fabricação de PLEDs foram sintetizados, tendo como finalidade unir em uma única camada emissiva, na forma de copolímeros ou na forma de blendas, materiais com propriedades transportadoras e injetoras de elétrons; grupos quinolina associados a materiais com elevadas propriedades de emissão de luz contendo grupos fluoreno. Esses copolímeros sintetizados, todos ainda não descritos na literatura ou em patentes, apresentaram rendimentos acima de 70% e rendimentos quânticos de fotoluminescência entre 60% e 83%, foram utilizados como camada emissiva na construção de PLEDs. Estes PLEDs foram caracterizados quanto ao seu comportamento elétrico através da obtenção de curvas de corrente em função da tensão (IxV) e dos espectros de eletroluminescência. Os resultados mostraram que a incorporação da quinolina aos copolímeros aumentou a sua estabilidade térmica, observada pela temperatura de inicio de degradação que elevou-se em até 80°C. Nos PLEDs, houve melhorias no balanceamento de cargas, dispensando até mesmo a deposição de uma camada adicional transportadora de elétrons (ETL). As tensões de operação desses dispositivos ficaram entre 2,0 e 5,2 V, com emissão entre 525 e 590nm. Esses materiais também tiveram as suas estruturas caracterizadas por ressonância magnética nuclear de hidrogênio, termogravimetria, calorimetria diferencial exploratória, espectroscopias no UV-Vis e no infravermelho, fluorimetria no UV-vis e cromatografia de permeação em gel. Filmes Langmuir e Langmuir- Blodgett dos copolímeros foram preparados e caracterizados por espectroscopia com luz polarizada de reflexão e absorção no infravermelho (PM-IRRAS) e por microscopia de força atômica (AFM). / New polymers and copolymers with a high potential for PLEDs constructions have been synthesized by Suzuki reaction and aims together in a single emissive layer in the form of copolymers or blended, materials with transporting and electron injection properties; quinoline groups linked to materials with high light emission properties as fluorene group. All these copolymers have not been described in literature or in patents, presented yields above 70%, quantum yields between 60% and 83% and were used as emissive layer in PLEDs. These PLEDs were characterized concerning their electrical behavior, by the characteristic J-V diode curves, and their electroluminescence. The results showed that the presence of quinoline increased its thermal stability at around 80° C and the PLEDs built with the synthesized copolymers do not need an extra ETL. The operating voltages of these devices were observed between 2.0 and 5.2 V with EL emission between 525 and 590nm. These new materials were also characterized by hydrogen nuclear magnetic resonance, thermogravimetry, differential scanning calorimetry, UV-Vis, Fluorescence and IR spectroscopy and gel permeation chromatography. Langmuir e Langmuir-Blodgett films were made and characterized by Polarization-Modulation Infrared Reflection-Absorption Spectroscopy (PM-IRRAS) and atomic force microscopy (AFM).
|
54 |
A New Approach to Benzo[h]quinoline SkeletonHuang, Chiao-wei 25 July 2007 (has links)
We use stepwise [3+3] annulation to prepare the asymmetric glutarimides, and then we can build substituent group in C6 position after choosing regioselective addition reaction. And we establish a new approach to benzo[h]quinoline skeleton starting from glutarimides via ring-closing reaction. Finally, we applied this method to the synthetic studies toward benzo[h]quinoline derivatives.
|
55 |
Studies toward the synthesis of the A-B ring system of lavendamycin methyl esterHorn, Mark A. 03 June 2011 (has links)
The synthesis of 7-amino-2-methylquinoline-5-8-dione (17) and 7-amino-3-methylquinoline-5,8-dione (157) are described.7-Amino-3-methylquinoline-5,8-dione (157) was prepared via alkaline hydrolysis of 7-acetamido-3-methylquinoline5,8-dione (149). 7-Acetamido-3-methylquinoline-5,8-dione (149) was prepared via the Diels-Alder reaction of 2-acetamido-6-bromo-1,4-benzoquinone (6) and 2-methyl-2propenal dimethylhydrazone (110).7-Amino-2-methylquinoline-5,8-dione (17) was prepared by the acid hydrolysis of 7-(triphenylphosphineimino)-2methylquinoline-5,8-dione (16). 7-(Triphenylphosphineimino)2-methylquinoline-5,8-dione (16) was prepared by tie treatment of 7-azido-2-methylquinoline-5,3-dione (15) with triphenylphosphine. 7-Azido-2-methylquinoline-5,8-dione (15) was prepared by treating 7-bromo-2-methylquinoline-5,8-dione (14) with sodium azide. The structures of the new compounds 15, 16, 17,149 and 157 were confirmed using MP, NMR, IR, MS and HRMS data. NMR, IR and MS data for known compounds 10, 11, 12, 13 and 14 are included for future reference.Ball State UniversityMuncie, IN 47306
|
56 |
Synthesis of DNA Minor Groove Binders and Investigation of Biophysical PropertiesLiu, Meng-Chi 18 January 2012 (has links)
I am interested in the design of DNA binding ligands which are including DNA minor groove binders and G-quadruplex stabilizing agents. Certain natural products, distamycin and belomycin are considered as models for designing new DNA binding agents. A variety of DNA binding ligands were synthesized and accordingly characterized by different bioassays. In the series of azo-pyrrole-polyamide, it showed slight DNA binding affinity but has the properties of DNA photo-cleavage and recognition of mixed sequence. The thiophene series showed strong binding ability for duplex DNA. Bithiophene series showed a remarkable binding affinity to duplex DNA which is compatible to natural products netropsin and distamycin. The pyridodicarboxamide series remain intramolecular hydrogen bonding with poor preferences for duplexes DNA even though they stabilized quadruplex DNA. The bithiophene-bipyrimidine compound binds to specific hexanucleotide sequence 5¡¦-AAGCTT-3¡¦ and acts as an unfused quadruplex stabilization ligand. In the quinoline series, the combination of quinoline and methylpyrrole polyamide proves the attenuation effect for quadruplexes stabilization which provides a novel strategy for development of quadruplex binding logands. In this study, several series of small molecules for DNA binding have been successfully synthesized and proved to interact with DNA secondary structures according to the particular properties of themselves.
|
57 |
Synthesis of DNA Minor Groove Binders with Diazine, Quinoline and Sugars moieties.Tung, Hung-Wei 28 August 2012 (has links)
Certain natural products, Ditamycin and Netropsin are considered as models of designing new DNA binding agents. A variety of DNA binding ligands were synthesized and accordingly characterized by different bioassays. In the series of azo-polyamide, it showed slight DNA binding affinity but has the properties of DNA photo-cleavage and recognition of mixed sequence. The carbohydrate-azo-polyamide series show the properties of DNA photo-cleavage and more effective in vitro experiment. In the quinoline series proves the attenuation effect for G-quadruplex stabilization which provides a novel strategy for development of G-quadruplex binding ligands.
|
58 |
The study of pH and ionic strength effects on the binding constant of nitrogen-contained polycyclic aromatic hydrocarbons and colloid organic matterHsu, Shih-han 24 August 2006 (has links)
In this study, we measured the binding constant, KCOC, between several humic acids and benzo(h)quinoline, a nitrogen contained PAHs via using fluorescence quenching method. KCOC of humic acids and phenanthrene, a parent PAHs, is also studied in comparison. Moreover, pH and ionic strength effect on the KCOC were investigated. According to our results, the phenanthrene¡¦s KCOC decreases as the pH increases due to the lower hydrophobicity of humic acid in higher pH values. The variation of benzo(h)quinoline¡¦s KCOC with pH exhibits a more complicated trend, with a maximum value at pH close to the pKb of benzo(h)quinoline. For pH lower than pKb, benzo(h)quinoline is protonated to be benzo(h)quinolinium, a cation, so that the ionic exchange is the dominant prosess in sorption mechanism. Therefore, the binding sites of humic acid increase with pH such that the KCOC increases with pH. In contrast, different mechanism involved in the binding for pH higher than pKb, neutral benzo(h)qunoline becomes dominant and hydrophobic interaction controls the binding prosess in sorption mechanism. At last, the composition of different functional groups of humic acid is also found significant in the binding affinity of benzo(h)qunoline or phenanthrene. Moreover, the benzo(h)qunoline¡¦s KCOC exhibits decreasing trend with increasing magnesium ionic strength because of the reduction of molecular size as well as the benzo(h)qunoline binding sites of humic acid. Findings from this study could provide valuable information for numerical simulation of transport and fates of HOPs in aquatic environment.
|
59 |
THERMAL STABILITY STUDIESKingston, David Ward, 1934- January 1966 (has links)
No description available.
|
60 |
NOVEL DUAL LEWIS ACID - LEWIS BASE BINDERS AS POTENTIAL HYDROGEN AND CARBONYL ACTIVATORSZhurakovskyi, Oleksandr January 2010 (has links)
A series of new “frustrated Lewis pairs” (FLPs), including chiral versions, with a predefined spatial relationship between the basic and acidic centers is proposed. Several synthetic protocols toward the targets were investigated: through an aryllithium-haloborane coupling; using organotin reagents and a chiral diazaborolidine; and through organoboranes RBH₂ as the boron component. Further development of the project is discussed in light of the discovered data. The intermolecular system consisting of 8-bromo-2-methylquinoline and (C₆F₅)₃B was shown to exist in the form of an FLP. This FLP is not capable of heterolytic H-H bond cleavage with formation of an isolable adduct either at 1 atm or at 4 atm of H₂.
|
Page generated in 0.059 seconds