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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
31

Dibenzophenazine And Quinoxaline Derivatives As Novel Visible Photosensitizers For Diaryliodonium Salts

Kolay, Merve 01 July 2011 (has links) (PDF)
This study is focused on the use of visible light in photoinitiated cationic polymerization. Photoinitiated polymerization of oxiranes, vinyl ethers, and other vinyl monomers was achieved. In doing so, (2-(2,3 dihydrobenzo [b][1,4]dioxin-6-yl)-3-(2,3-dihydrobenzo[b]-[1,4]dioxin-7-yl)-5-(2,3-dihydrothieno[3,4-b][1,4]dioxin-5-yl)-8-(2,3-dihydrothieno[3,4-b][1,4]dioxin-7yl) quinoxaline) (DBQEd) and poly(2,3,5,8-tetra(thiophen-2-yl)quinoxaline) (TTQ), two dibenzo[a,c]phenazine derivatives / 10,13-bis(2,3-dihydrothieno[3,4-b][1,4]dioxin-5-yl)dibenzo[a,c] phenazine (PHED) and 10,13-bis(4-hexylthiophen-2-yl)dibenzo[a,c]phenazine (PHEHT) were utilized as the photosensitizers for diaryliodonium salt photoinitiators. Novel dyes based on the dibenzo[a,c]phenazine and quinoxaline skeleton were shown to be efficient in carrying out the cationic photopolymerizations of a wide variety of epoxide, oxetane, and vinyl monomers at room temperature upon irradiation with long-wavelength UV and visible light. The polymerizations were initiated at room temperature in the presence of diphenyliodonium hexafluorophosphate (Ph2I+PF-6) and monitored by optical pyrometry (OP). The photopolymerization of an epoxide monomer via solar irradiation was also demonstrated.
32

Syntheses Of Benzotriazole Bearing Donor Acceptor Type Random Copolymers For Full Visible Light Absorption

Oktem, Gozde 01 September 2011 (has links) (PDF)
The synthesis and preliminary optoelectronic properties of a series of donor-acceptor (DA) type polymers differing by the acceptor units in the polymer backbone were investigated. Polymers CoP1, CoP2 and CoP3 were designed to yield alternating DA segments with randomly distributed different acceptor units along polymer backbone. The combination of neutral state red colored and neutral state green colored materials resulted in different neutral state colors with respect to their additional acceptor unit. 5,8-Dibromo-2,3-bis(4-tert-butylphenyl) quinoxaline, 5,8-dibromo-2,3-di(thiophen-2-yl)quinoxaline and 4,7-dibromobenzo[c][1,2,5]selenadiazole units were perceived as additional acceptor units and these constituents were combined with the 4,7-dibromo-2-dodecyl-2H-benzo[d][1,2,3]triazole unit and the 2,5-bis(tributylstannyl)thiophene moiety via Stille coupling. The resultant donor acceptor type random copolymers indicated that possessing 5,8-dibromo-2,3-di(thiophen-2-yl)quinoxaline as an extra electron deficient with 4,7-dibromo-2-dodecyl-2H-benzo[d][1,2,3]triazole unit on the same polymer backbone originated a neutral state black colored copolymer along with spanning the entire visible spectrum.
33

Synthesis And Electrochromic Properties Of Conducting Copolymers Of Dioxocino- And Dithiocino- Quinoxalines With Bithiophene

Beyazyildirim, Seniz 01 June 2005 (has links) (PDF)
Two new monomers / 2-benzyl-5,12-dihydro-2Hpyrrolo[ 3&rsquo / ,4&rsquo / :2,3][1,4]dioxocino[6,7-b]quinoxaline (DPOQ) and 5,12- dihydrothieno[3&rsquo / ,4&rsquo / :2,3][1,4]dithiocino[6,7-b]quinoxaline (DTTQ), were synthesized. The chemical structures of the monomers were characterized by Nuclear Magnetic Resonance (1H-NMR), Fourier Transform Infrared (FTIR) and Mass Spectrometry (MS). Copolymer of DPOQ with bithiophene (BT) was synthesized via potentiostatic electrochemical polymerization in acetonitrile (ACN)-tetrabutylammonium tetrafluoroborate (TBAFB) solvent-electrolyte couple. For DTTQ, copolymerization with bithiophene was achieved via potentiodynamic method in dichloromethane (DCM)-tetrabutylammonium hexafluorophosphate (TBAFP) solvent-electrolyte couple. Characterizations of the resulting copolymers were performed by cyclic voltammetry (CV), FTIR, Scanning Electron Microscopy (SEM) and UV-Vis Spectroscopy. Four-probe technique was used to measure the conductivities of the samples. Moreover, the spectroelectrochemical and electrochromic properties of the copolymer films were investigated. In addition, dual type polymer electrochromic devices (ECDs) based on P(DPOQ-co-BT) and P(DTTQ-co-BT) with poly(3,4- ethylenedioxythiophene) (PEDOT) were constructed. Spectroelectrochemistry, electrochromic switching and open circuit stability of the devices were studied. They were found to have good switching times, reasonable contrasts and optical memories.
34

Water-Soluble Helical Polymers as Chiral Catalysts in Asymmetric Reactions in Water / 水中不斉反応のキラル触媒のための水溶性らせん高分子

Kamiya, Naoaki 23 May 2023 (has links)
京都大学 / 新制・課程博士 / 博士(工学) / 甲第24817号 / 工博第5160号 / 新制||工||1986(附属図書館) / 京都大学大学院工学研究科合成・生物化学専攻 / (主査)教授 杉野目 道紀, 教授 生越 友樹, 教授 大内 誠 / 学位規則第4条第1項該当 / Doctor of Philosophy (Engineering) / Kyoto University / DGAM
35

Síntese de biblioteca de derivados quinoidais e quinoxalínicos visando à atividade biológica / Synthesis of library of quinoidal and quinoxaline derivatives aiming biological activity

Franco, Márcia Silvana Freire 13 June 2017 (has links)
Nesta tese são apresentados, em dois capítulos, os resultados da reatividade química de quinoxalinas e os estudos visando à síntese de quinona natural, a vegfrecina. Modificações específicas em estruturas privilegiadas, padrões estruturais relevantes para bioatividade, representam uma alternativa viável na busca de novos ligantes para alvos macromoleculares. Neste cenário, as quinoxalinas apresentam destacada importância no âmbito da química medicinal, sendo assim é de grande importância o desenvolvimento de metodologias de funcionalização que conduzam a diversidade molecular deste núcleo. Neste contexto, foram realizadas reações de ativação C - H, como uma estratégia para a síntese de derivados vinil quinoxalinicos, com base na abordagem de Fujiwara-Moritani. Os resultados obtidos com este estudo indicaram que a densidade eletrônica das olefinas utilizadas neste estudo foi determinante para o rendimento reacional. Assim, as reações envolvendo olefinas ricas em elétrons, resultaram em maior rendimento do produto alquenilado, alcançando 89%. A deoxidação ocorreu em rendimentos de 43 - 54%, levando a ampliação da coleção de compostos desenvolvidos neste projeto. Os compostos aqui desenvolvidos foram testados quanto à atividade antimicobacteriana, entretanto, nenhum deles apresentou resultados promissores. O segundo capítulo desta tese abordou a síntese da Vegfrecina, que possui seletividade de inibição dos receptores do fator de crescimento endotelial vascular (VEGFR), bloqueando a ativação de VEGFR-1 e VEGFR-2 e, consequentemente, interferindo na vascularização, proliferação e metástase tumoral. Nossa estratégia utilizou o intermediário chave 6-Bromo-5,8-dimetoxi-2,2-dimetil-2,3-dihidroquinazolin-4(1H)-ona em reações de aminação de Buchwald Hartwig com três anilinas diferentes. Embora tenhamos obtido três intermediários sintéticos inéditos, em bons rendimentos, a etapa de oxidação não foi promissora, impossibilitando a obtenção da Vegfrecina e de seus análogos. / The study of chemistry reactivity of quinoxalines and the study aiming total syntheses of natural quinone, vegfrecine, are shown in this thesis in two chapters. The specific modifications privileged scaffold represents a promising way following for new macromolecular ligands targets. Considering the great importance of quinoxaline core in medicinal chemistry, the development of efficient methodologies in orther to obtain molecular diversity have attracted large attention. In this context, using Fujiwara-Moritani approach the C-H activation reactions were performed as good strategy in synthesis of vinyl- quinoxaline derivatives. Our results indicated the importance of olefin electron density in the reaction yields. In this way, reactions involving high electron density olefines, results in the high alkenilated products, achieving 89% of yield. The deoxygenation process occurred in yields of 43 until 54. The compounds obtained were tested against Mycobacterium tuberculosis, however no primissing results were observed. The second chapter in this thesis show our attempt to total synthesis of Vegfrecine, that have inhibitory activity of vascular endothelial growth factor receptor (VEGFR), Our strategy used the 6-bromo-5,8-dimethoxy-2,2-dimethyl-2,3-dihydroquinazolin-4(1H)-one in Buchwald Hartwig reaction with three different olefins. Although these new synthetic intermediates were obtained with good yield, the last step of oxidation didn\'t work. Therefore, it was not possible to obtain the Vegfrecine and its analogous.
36

Síntese de biblioteca de derivados quinoidais e quinoxalínicos visando à atividade biológica / Synthesis of library of quinoidal and quinoxaline derivatives aiming biological activity

Márcia Silvana Freire Franco 13 June 2017 (has links)
Nesta tese são apresentados, em dois capítulos, os resultados da reatividade química de quinoxalinas e os estudos visando à síntese de quinona natural, a vegfrecina. Modificações específicas em estruturas privilegiadas, padrões estruturais relevantes para bioatividade, representam uma alternativa viável na busca de novos ligantes para alvos macromoleculares. Neste cenário, as quinoxalinas apresentam destacada importância no âmbito da química medicinal, sendo assim é de grande importância o desenvolvimento de metodologias de funcionalização que conduzam a diversidade molecular deste núcleo. Neste contexto, foram realizadas reações de ativação C - H, como uma estratégia para a síntese de derivados vinil quinoxalinicos, com base na abordagem de Fujiwara-Moritani. Os resultados obtidos com este estudo indicaram que a densidade eletrônica das olefinas utilizadas neste estudo foi determinante para o rendimento reacional. Assim, as reações envolvendo olefinas ricas em elétrons, resultaram em maior rendimento do produto alquenilado, alcançando 89%. A deoxidação ocorreu em rendimentos de 43 - 54%, levando a ampliação da coleção de compostos desenvolvidos neste projeto. Os compostos aqui desenvolvidos foram testados quanto à atividade antimicobacteriana, entretanto, nenhum deles apresentou resultados promissores. O segundo capítulo desta tese abordou a síntese da Vegfrecina, que possui seletividade de inibição dos receptores do fator de crescimento endotelial vascular (VEGFR), bloqueando a ativação de VEGFR-1 e VEGFR-2 e, consequentemente, interferindo na vascularização, proliferação e metástase tumoral. Nossa estratégia utilizou o intermediário chave 6-Bromo-5,8-dimetoxi-2,2-dimetil-2,3-dihidroquinazolin-4(1H)-ona em reações de aminação de Buchwald Hartwig com três anilinas diferentes. Embora tenhamos obtido três intermediários sintéticos inéditos, em bons rendimentos, a etapa de oxidação não foi promissora, impossibilitando a obtenção da Vegfrecina e de seus análogos. / The study of chemistry reactivity of quinoxalines and the study aiming total syntheses of natural quinone, vegfrecine, are shown in this thesis in two chapters. The specific modifications privileged scaffold represents a promising way following for new macromolecular ligands targets. Considering the great importance of quinoxaline core in medicinal chemistry, the development of efficient methodologies in orther to obtain molecular diversity have attracted large attention. In this context, using Fujiwara-Moritani approach the C-H activation reactions were performed as good strategy in synthesis of vinyl- quinoxaline derivatives. Our results indicated the importance of olefin electron density in the reaction yields. In this way, reactions involving high electron density olefines, results in the high alkenilated products, achieving 89% of yield. The deoxygenation process occurred in yields of 43 until 54. The compounds obtained were tested against Mycobacterium tuberculosis, however no primissing results were observed. The second chapter in this thesis show our attempt to total synthesis of Vegfrecine, that have inhibitory activity of vascular endothelial growth factor receptor (VEGFR), Our strategy used the 6-bromo-5,8-dimethoxy-2,2-dimethyl-2,3-dihydroquinazolin-4(1H)-one in Buchwald Hartwig reaction with three different olefins. Although these new synthetic intermediates were obtained with good yield, the last step of oxidation didn\'t work. Therefore, it was not possible to obtain the Vegfrecine and its analogous.

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