Bibliografias temáticas / Photo-cyclization

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Literatura científica selecionada sobre o tema "Photo-cyclization"

Autor: Grafiati

Publicado: 2 de novembro de 2024

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Artigos de revistas sobre o assunto "Photo-cyclization"

Zhao, Lishuang, Hongyue Zhang, Jianing Cui, Meiqi Zhao, Zhiqiang Wang, Qunfeng Yue e Yingxue Jin. "Photo-induced synthesis and in vitro antitumor activity of Fenestin A analogs". New Journal of Chemistry 41, n.º 23 (2017): 14044–48. http://dx.doi.org/10.1039/c7nj03363j.

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Yao, Zhuojun, Xueting Wu, Xiaocui Zhang, Qin Xiong, Shichao Jiang e Zhipeng Yu. "Synthesis and evaluation of photo-activatable β-diarylsydnone-l-alanines for fluorogenic photo-click cyclization of peptides". Organic & Biomolecular Chemistry 17, n.º 28 (2019): 6777–81. http://dx.doi.org/10.1039/c9ob00898e.

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Rajeshkumar, Venkatachalam, e Mihaiela C. Stuparu. "A photochemical approach to aromatic extension of the corannulene nucleus". Chemical Communications 52, n.º 64 (2016): 9957–60. http://dx.doi.org/10.1039/c6cc04910a.

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Connor, Dennis A., Donald R. Arnold, Pradip K. Bakshi e T. Stanley Cameron. "Photochemical nucleophile–olefin combination, aromatic substitution (photo-NOCAS) reaction. Part 9: methanol-2,6-dimethyl-1,6-heptadiene, and 1,4-dicyanobenzene". Canadian Journal of Chemistry 73, n.º 6 (1 de junho de 1995): 762–71. http://dx.doi.org/10.1139/v95-096.

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The photochemical nucleophile–olefin combination, aromatic substitution (photo-NOCAS) reaction of methanol, 2,6-dimethyl-1,6-heptadiene, and 1,4-dicyanobenzene yields three distinct types of 1:1:1 adducts: an acyclic product, 4-(1-methoxymethyl-1,5-dimethyl-5-hexenyl)benzonitrile (8, 5%); a cis–trans pair of cyclohexanes, 4-(3-methoxymethyl-1,3-dimethylcyclohexyl)benzonitrile (9cis (12%) and 9trans (11%)); and a cis–trans pair of cycloheptanes, 4-(4-methoxy-1,4-dimethylcycloheptyl)benzonitrile (10cis (12%) and 10trans (10%)). Variation in the concentration of the nucleophile, methanol, and codonor, biphenyl, affects the product ratio and it has been possible to establish the mechanisms for the formation of these products. The acyclic product is formed by a typical photo-NOCAS reaction, that is, addition (anti-Markovnikov) across one of the heptadiene double bonds. The cyclohexane products are formed following 1,6-endo cyclization of the intermediate β-alkoxy radical. And the cycloheptane products result from 1,7-endo,endo cyclization of the initially formed 2,6-dimethyl-1,6-heptadiene radical cation. Comparison of the relative rates of these cyclization processes can be made with those of the next smaller homolog, 2,5-dimethyl-1,5-hexadiene. Keywords: photochemistry, photoinduced electron transfer, radical ions, radicals, cyclization.

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Chen, Ling, Yu-Ming Cui, Zheng Xu, Jian Cao, Zhan-Jiang Zheng e Li-Wen Xu. "An efficient approach toward formation of polycyclic coumarin derivatives via carbocation-initiated [4+2] cycloaddition and atom-economical photo-irradiated cyclization". Chemical Communications 52, n.º 74 (2016): 11131–34. http://dx.doi.org/10.1039/c6cc05698a.

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Polycyclic coumarin derivatives were easily prepared by carbocation initiated [4+2] cycloaddition of propargyl silyl ethers with ynamides and fluorescent analysis-oriented photo-irradiated cyclization.

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Kim, Kyung-su, You Kyoung Chung, Hyunwoo Kim, Chae Yeon Ha, Joonsuk Huh e Changsik Song. "Additive-free photo-mediated oxidative cyclization of pyridinium acylhydrazones to 1,3,4-oxadiazoles: solid-state conversion in a microporous organic polymer and supramolecular energy-level engineering". RSC Advances 11, n.º 4 (2021): 1969–75. http://dx.doi.org/10.1039/d0ra09581h.

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Mizutsu, Ryo, Ryosuke Asato, Colin J. Martin, Mihoko Yamada, Yoshiko Nishikawa, Shohei Katao, Miku Yamada, Takuya Nakashima e Tsuyoshi Kawai. "Photo-Lewis Acid Generator Based on Radical-Free 6π Photo-Cyclization Reaction". Journal of the American Chemical Society 141, n.º 51 (8 de dezembro de 2019): 20043–47. http://dx.doi.org/10.1021/jacs.9b11821.

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Arnold, Donald R., Kimberly A. McManus e Xinyao Du. "Photochemical nucleophile–olefin combination, aromatic substitution (photo-NOCAS) reaction. Part 6: methanol, nonconjugated dienes, and 1,4-dicyanobenzene". Canadian Journal of Chemistry 72, n.º 2 (1 de fevereiro de 1994): 415–29. http://dx.doi.org/10.1139/v94-063.

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Irradiation, through Pyrex, of an acetonitrile–methanol (3:1) solution of 1,4-dicyanobenzene (1) and 1,5-hexadiene (9) leads to formation of ortho and meta cyclic adducts (13–16) arising from the intermediate exciplex. There was no evidence for interaction between the two double bonds of this nonconjugated diene. The oxidation potential of 9 is high enough (> 3 V vs. sce) to preclude single electron transfer (SET); no photo-NOCAS products are formed. Similar irradiation of acetonitrile–methanol solutions of 1 and 2-methyl-1,5-hexadiene (10) does yield a photo-NOCAS product (17); reaction occurs only on the more heavily substituted double bond. The additional substitution on the double bond lowers the oxidation potential (2.70 V vs. sce) of this diene to the point where SET from 10 to the excited singlet state of 1 can occur. In this case, no cycloaddition products are formed; the exciplex is quenched by electron transfer. There was no evidence for interaction between the two double bonds of the initially formed radical cation 10+•, or between the terminal double bond and the β-alkoxyalkyl radical of the intermediate leading to the photo-NOCAS product. The photo-NOCAS product (19) was also formed when 2,5-dimethyl-1,5-hexadiene (11) was subjected to these reaction conditions. In this case, when biphenyl (4) was added as a codonor, in addition to the photo-NOCAS product, products (21cis and trans) resulting from cyclization of the initially formed acyclic radical cation 11+• to give the 1,4-dimethylcyclohexane-1,4-diyl radical cation were also observed. This 1,6-endo, endo cyclization of 11+• must be rapid enough to compete with reaction with methanol. There was no evidence for cyclization (neither 1,4-exo nor 1,5-endo) of the intermediate β-alkoxyalkyl radical. When the radical cation of 2,5-dimethyl-1,4-hexadiene (12+•) is generated under these reaction conditions, photo-NOCAS products 22 and 23 are formed at the more heavily substituted double bond, along with the conjugated tautomer 2,5-dimethyl-2,4-hexadiene (24). The mechanisms for these transformations are discussed.

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Zhou, Zhao-Zhao, Jia-Hui Zhao, Xue-Ya Gou, Xi-Meng Chen e Yong-Min Liang. "Visible-light-mediated hydrodehalogenation and Br/D exchange of inactivated aryl and alkyl halides with a palladium complex". Organic Chemistry Frontiers 6, n.º 10 (2019): 1649–54. http://dx.doi.org/10.1039/c9qo00240e.

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Photo-induced radical reductive dehalogenation of inactivated aryl/alkyl bromides and chlorides with a palladium complex is described. Reductive cyclization, dehalogenative deuteration, and radical addition process can be achieved smoothly.

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Sun, Bin, Rongcheng Shi, Kesheng Zhang, Xiaoli Tang, Xiayue Shi, Jiayun Xu, Jin Yang e Can Jin. "Photoinduced homolytic decarboxylative acylation/cyclization of unactivated alkenes with α-keto acid under external oxidant and photocatalyst free conditions: access to quinazolinone derivatives". Chemical Communications 57, n.º 49 (2021): 6050–53. http://dx.doi.org/10.1039/d1cc02415a.

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A green and efficient strategy for the synthesis of quinazolinone derivatives via photo-induced decarboxylative cascade radical acylation/cyclization of unactivated alkenes has been developed under oxidant and photocatalyst free conditions.

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Mais fontes

Teses / dissertações sobre o assunto "Photo-cyclization"

Andrieux, Vivien. "Matériaux mous supramoléculaires électro-stimulables obtenus par auto-assemblage de viologènes". Electronic Thesis or Diss., Lyon, École normale supérieure, 2024. http://www.theses.fr/2024ENSL0038.

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L’objectif de cette thèse est de développer des matériaux souples supramoléculaires sensibles aux stimuli électrochimiques. La stratégie de préparation et de stimulation de tels matériaux est basée sur les propriétés d’auto-assemblage d’unités moléculaires dérivés de sels de 4,4-bipyridinium (viologènes). Ce travail de thèse développe en particulier l’étude de la structure, le mécanisme de formation et la stimulation par transfert d’électrons de gels supramoléculaires conducteurs obtenus par auto-assemblage d’un viologène substitué par des groupements cholestéryles. Dans une première partie bibliographique, nous décrivons les caractéristiques principales des gels supramoléculaires, les problématiques associées à la caractérisation et à la stimulation électrique de ce type de matériau, ainsi que le potentiel des viologènes pour le développement de nouveaux gels supramoléculaires électron-responsifs. La deuxième partie de ce manuscrit est dédiée à la description du travail de synthèse, de formulation et de caractérisation ayant permis d’obtenir un gel supramoléculaire de viologène conducteur, présentant des propriétés idéales pour la stimulation électrochimique et la caractérisation in situ de la réponse du matériau. La stimulation par transfert d’électrons (photo-induit ou électrochimique) de gels de viologène conducteurs est décrite dans une troisième partie. Celle-ci décrit en détails les différentes stratégies utilisées pour permettre la réduction des unités viologène immobilisées au sein du réseau supramoléculaire structurant les gels. Ces travaux ont permis de mettre en évidence un des premiers systèmes capables de polymérisation et de dépolymérisation supramoléculaires induites par stimulation électrochimique
The aim of this thesis is to develop electron-responsive supramolecular soft-materials. The strategy for the preparation and stimulation of such materials is based on the self-assembly properties of molecular units derived from 4,4-bipyridinium salts (viologens). The thesis research work carried has been focused on the structural characterizations, the study of gelation mechanism and the stimulation (electrochemical reduction or photo-reduction) of conductive gels obtained through the self-assembly of a cholesteryl substituted viologen. A first bibliographic part will describe the principal features of supramolecular gels, the challenges related to their characterization and electric stimulation and the potential of viologen-based supramolecular gels for the development of new electron-responsive supramolecular gels. The second part of the manuscript is devoted to present the experimental work performed for the synthesis, the formulation and the characterizations that led to the design of a conductive viologen-based supramolecular gel exhibiting ideal properties for electrochemical stimulation and in situ monitoring. The stimulation of conductive viologen gels, consisting in the electrochemical reduction or photoreduction are described in a third part. This part describes in details the different strategies used to reach an efficient reduction of the viologen moieties which are entrapped in the gel supramolecular network. This work demonstrates that the studied viologen gel is one of the very first systems able to undergo reversible electrochemically induced supramolecular polymerization and de-polymerization

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張文昇. "Photo-cyclization of a-iodo cycloalkanones bearing an allenic side chain". Thesis, 2001. http://ndltd.ncl.edu.tw/handle/56860367154407452025.

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碩士
國立清華大學
化學系
89
The main goal of the synthesis is to study the Photo-induced cyclization reaction of α- iodo cycloalkanones bearing an allenic side chain. We first use the α- iodo cycloalkanone compound 71a-b as starting material, introduce the side chain of allene from β-position successfully by 1,4-Michael addition and then follow with Photo-induced Electron Transfer（PET） cyclization reaction, we obtain the 5、5-fused, 6、5-fused bicycle compounds 73a-b and 74a-c. Besides, we compare the difference of reaction by using Iodide and Slow-addition radical cyclization. From the results, we conclude that the products are all the same. It is avoidable to use the reagent that generate radical because of the allenic side chain can proceed the Photo-induced Electron Transfer cyclization reaction. It is also more convenient of purification. We can construct the structure of 5、5-fused and 6、5-fused bicycle compounds efficient and take advantage of in the synthesis of natural compounds such as (+)-Axamide-4 or (+)-Axisonitrile-4.

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