Dissertationen zum Thema „Isochromans“
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Joll, Cynthia Ann. „The asymmetric synthesis of isochromans related to the aphid pigments“. Thesis, Joll, Cynthia Ann (1995) The asymmetric synthesis of isochromans related to the aphid pigments. PhD thesis, Murdoch University, 1995. https://researchrepository.murdoch.edu.au/id/eprint/51655/.
Der volle Inhalt der QuelleMuller, Cyprien. „Supramolecular catalysis and vibrational strong coupling : how to influence chemical reactivity ?“ Electronic Thesis or Diss., Strasbourg, 2024. http://www.theses.fr/2024STRAF014.
Der volle Inhalt der QuelleHow can we influence chemical reactivity? Throughout this thesis, I attempted to answer this question by exploring the frontier between chemistry and physics.First, I took advantage of solvent 1,1,1,3,3,3-hexafluoroisopropanol (HFIP) which often unlocks exotic reactivity that can be explained by its extraordinary physical properties. These properties make of HFIP a veritable supramolecular matrix, which allowed the development of a new method for the synthesis of densely functionalized isochromans. This method displayed unprecedented generality, simplicity, and practicality on the way to this pharmacologically important motif.Second, I investigated how light-matter hybridization, accessed through Vibrational Strong Coupling (VSC) could alter the kinetics of some chemical reactions. In practice, by placing different reactants between two mirrors, I studied the impact of VSC on nucleophilicity, as well as on Diels-Alder reactivity
Fronert, Jeanne Katrin [Verfasser]. „Organokatalytische asymmetrische Synthesen von Dihydrobenzofuranen und Isochroman-1-onen / Jeanne Katrin Fronert“. Aachen : Hochschulbibliothek der Rheinisch-Westfälischen Technischen Hochschule Aachen, 2015. http://d-nb.info/1080490825/34.
Der volle Inhalt der QuelleHabert, Loïc. „Synthèse et étude de la réactivité d'ynamides. Application pour la synthèse de composés azotés d'intérêts biologiques“. Thesis, Orléans, 2018. http://www.theses.fr/2018ORLE2065.
Der volle Inhalt der QuelleThe constant demand for original small molecule collections with promesing therapeutic potential have required the development of new and efficient synthetic methods. Given the nitrogen ubiquity in nature and in life sciences, the aim of this work is the development of original heterocyclic building blocks, originated from the functionalization of ynamide frameworks. Our goal was to study the reactivity of ynamides in order to synthesize from a common skeleton small library of nitrogen or oxygen compounds with biological relevance. The implementation of a new innovative methodology has been necessary, while trying to adhere to the following principles: atom economy, catalytic reaction, fast synthesis in minimal steps, and control of chemo- and regioselectivity.Firstly, we studied the carbozincation reaction of ynamides allowing access to several substituted enamides. Subsequently, cycloisomerization reaction of yne-carbamates has allowed us the development of two novels methodologies using zinc (II) or rhodium (II) salts, which provide access to oxazolone scaffolds. Our research has been studying the keteniminium ion intermediates accessible via an acid activation of ynamide. The development of two methods for the 3-amino-isocoumarin core was achieved via addition of Lewis or Brønsted acid or via electrophilic cyclization. Finally, a tandem coupling / cycloisomerization / nucleophilic addition reaction was carried out in order to prepare 1H-isochromene
Lewis, Shane E. „Development of a Three Step Cascade Synthesis of 2,4-Dihydro-1H-benzo[f]isochromenes“. W&M ScholarWorks, 2015. https://scholarworks.wm.edu/etd/1539626965.
Der volle Inhalt der QuelleCoelho, Paulo. „Etude de la diastereoselectivite des reactions intramoleculaires de composes presentant un atome de silicium chiral. Synthese de derives de 4-silatetrahydro-isochroman-1-ones, de 4-sila-2h-isoquinolein-1-ones et de silacycloalcanes“. Paris 11, 1995. http://www.theses.fr/1995PA112069.
Der volle Inhalt der QuelleMariaule, Gaëlle. „Accès original aux hétérocycles par la catalyse organométallique : développement de nouveaux inhibiteurs de kinases“. Thesis, Paris 5, 2014. http://www.theses.fr/2014PA05P612/document.
Der volle Inhalt der QuelleMy thesis proJect is organized around two main topics having in common organometallic chemistry and the synthesis of heterocycles.Firstly, we were interested in a methodology for the synthesis of tetrahydrocyclopenta[c]acridines. These compounds are synthesized in three steps from various quinolines. The key step is a cobalt-Catalyzed intramolecular Pauson-Khand reaction. Some compounds of this family exhibit selective Cyclin Dependent Kinases (CDKs) inhibition, particulary against CDK2, in the submicromolar range. A hit compound has been identified, and then using data from co-Crystallization with CDK2 and molecular modeling, followed by the study of structure-Activity relationships, the rational design of a second generation of molecules has been investigated. The most advanced compound has an IC50 of 300 nM against CDK2/cyclin A with an excellent metabolic profile. In the second axis of research, we have studied and developed a new silver-Catalyzed tandem addition/cyclization reaction with carbon nucleophiles. The systems studied are (hetero)aromatics compounds having an aldehyde group and in ortho-Position an alkynyl group. The synthetic strategy leads to 1H-Isochromene derivatives by creating two new bonds. A thorough study of the tandem reaction allowed us to obtain a wide range of isochromene derivatives, highlighting the influence of different substituents carried by the alkyne group or on the (hetero)aromatic substrates; and also to investigate the use of different carbon nucleophiles (alkynes, aromatics and heteroaromatics). The limitations of the tandem reaction have also been identified
Gorgoi, Mihaela. „Electronic Properties of Phthalocyanines Deposited on H-Si(111)“. Doctoral thesis, Universitätsbibliothek Chemnitz, 2007. http://nbn-resolving.de/urn:nbn:de:swb:ch1-200700213.
Der volle Inhalt der QuelleIn the context of this work four Phthalocyanine were studied: Metal-free Phthalocyanine (H2Pc), Copper Phthalocyanine (CuPc) and fluorine-substituted Phthalocyanine (F4CuPc and F16CuPc). The goal of this work is the electronic and chemical characteristics of the interfaces. The molecules were deposited by organic molecular beam deposition (OMBD) in the ultra high vacuum on hydrogen-passivated Si(111)-Substrate. Surface sensitive techniques such as photoemission spectroscopy (PES), bremsstrahlung isochromate spectroscopy (BIS or IPES - inverse photoemission spectroscopy) and near edge X-ray absorption fine structure spectroscopy (NEXAFS) were used for characterisation. Theoretical computations by density functional theory methods were employed, in order to assign different components in PES and IPES. The energy level alignment at the organic/H-Si interface, as well as the transport gap of H2Pc, CuPc, F4CuPc and F16CuPc were determined by PES and IPES. The NEXAFS measurements determine the exact molecular orientation with respect to the substrate. The evaluation of the data showed different molecular orientation in the thin and thick films. This change was correlated with the band bending like behaviours that emerged at these interfaces. In addition to the band bending like behaviour, the interfaces show also an interface dipole which is driven by the work function difference between the contact materials. The influence of the degree of fluorination is confirmed in the similar increase of the EA, WF and IE. The electronic properties of metal/organic layer interfaces and of organic layer under oxygen influence were examined by PES and IPES. The Ag/Pc interfaces show a mixture of HOMO-LUMO shifts and interface dipole formation. A charge transfer complex is formed in the case of Ag/H2Pc and Ag/F16CuPc interfaces. Ag is physisorbed atop the CuPc. Charge transfers from F4CuPc to Ag creating a continuous n-type doping at the interface. Similar to the Pc/H-Si interfaces the interface dipoles found here show a linear dependence on the EA, WF and IE and can be predicted by the difference in the work functions. The data evaluation of oxygen exposed thick films determined two groups of behaviours. The weak interaction group is represented by H2Pc and F4CuPc, Pcs on which oxygen is physisorbed. The strong interaction group contains the other two molecules CuPc and F16CuPc. CuPc forms a charge transfer complex with oxygen and on top of F16CuPc a polarized layer is formed
Gina, Ervin. „Implementation and Optimization of an Inverse Photoemission Spectroscopy Setup“. Scholar Commons, 2012. http://scholarcommons.usf.edu/etd/4050.
Der volle Inhalt der QuelleSenanayake, Badra Sriyani. „Approaches to natural isochromans by isomerisation of aryldioxolanes“. Phd thesis, 1992. http://hdl.handle.net/1885/138963.
Der volle Inhalt der QuelleWei-Hsiang, Hung, und 洪偉翔. „A Synthesis of Isochromans Via Claisen Rearrangement and Intramolecular Cyclization“. Thesis, 2004. http://ndltd.ncl.edu.tw/handle/95048723709620156052.
Der volle Inhalt der Quelle高雄醫學大學
藥學研究所碩士在職專班
92
英文摘要 In this study, 2-allyloxyisovanillin ( 2 ), prepared from isovanillin ( 1 ), was heated at higher temperature ( 180 ℃) to undergo the Claisen rearrangement to furnish 2-allyl-3-hydroxy-4-methoxybenzaldehyde ( 3 ). Based on O-alkylation and reduction ,compound 3 was converted into 3-alkyloxy-2-allyl-4-methoxybenzyl alcohol ( 5 ) in good yields. Followed by the treatment of compound 5 with potassium tert-butoxide to undergo the isomerization of the allylic double bond, and concomitantly to undergo the sp2-endo trigonal intramolecular cyclization, gave a series of new substituted isochromans in moderate yields.
Govender, Sameshnee. „Methodology for the Enantioselective Synthesis of Isochromanes and their Dimers“. Thesis, 2006. http://hdl.handle.net/10539/1713.
Der volle Inhalt der QuellePyranonaphthoquinones are biologically important molecules found in a wide variety of bacteria, microbial fungi and plant species. Their biological activity is proposed to be a consequence of their ability to function as bioreductive alkylating agents. This class of compounds, which include monomeric and dimeric examples, contain the basic naphtho[2,3-c]pyran-5,10-dione skeleton, usually with substituents at the C-1 and C-3 positions of the pyran ring. The aim of the first part of the project was to develop a novel method for the synthesis of enantiomerically pure 5,8-dimethoxy-isochroman-4-ol, which will provide a handle for stereoselectively adding substituents to the C-1 and C-3 positions of the pyran nucleus. In the second part of the project we wished to attempt to synthesize the naturally occurring compound, cardinalin 3, the dimer of ventiloquinone L previously synthesized in the Wits laboratories. The synthesis of the enantiomerically pure isochromanol began with 2,5-dihydroxybenzoic acid, which was subjected to a diallylation followed by a Claisen rearrangement. The phenols were protected by a methylation reaction and the ester moiety was reduced to give (2-allyl-3,6- dimethoxyphenyl)methanol. It was then allylated to produce a suitable precursor for a one pot/two step ruthenium mediated isomerisation/ring closing metathesis reaction to produce 5,8-dimethoxy-1H-isochromene in an overall yield of 47%. It was converted to racemic 5,8-dimethoxy-isochroman-4-ol through a hydroboration-oxidation reaction in a yield of 84%. The separation of the enantiomers was achieved by acetylating the alcohol to form 5,8-dimethoxy-3,4-dihydro-1H-isochromen-4-yl acetate and then a lipase enzyme was used to stereospecifically deacetylate one enantiomer, while leaving the other enantiomer untouched. The second part of the dissertation discusses the progress towards the synthesis of cardinalin 3. This project began with the formation of the C-C biaryl axis starting from 1,3-dimethoxybenzene. The synthesis then continued with the diformylation of the biphenyl to give 2,2’,6,6’-tetramethoxy[1,1′-biphenyl]-3,3′-dicarbaldehyde. This was subjected to a Stobbe condensation and a Friedel-Crafts acylative cyclisation to produce diethyl [4,4′-diacetoxy-6,6′,8,8′-tetramethoxy-7,7′-binaphthalene]-2,2′- dicarboxylate. The synthesis will be continued in the PhD, using methodology previously developed for the formation of the monomer, as well as methodology developed here.
Chan, Yi-Ling, und 詹翊翎. „Three-step synthesis of substituted isochromenes“. Thesis, 2016. http://ndltd.ncl.edu.tw/handle/87995610283645869346.
Der volle Inhalt der Quelle高雄醫學大學
醫藥暨應用化學系碩士班
104
Isochromenes and related cyclic ether structures can be widely seen in various biologically active compounds and also common structural units in natural products. Therefore, using simple and easy way to obtain what we want is a very important challenge in modern organic synthesis and also caused considerable concern. According to literature most of the structure that contains aldehydes or alcohols together with alkynes to cyclization process. And this process is to make use of transition metal or inorganic complex to catalytic action, then form the structure of cyclic ethers. In today’s development of environmentally conscious towards green chemistry, we used potassium carbonate salt in the process of cyclization reaction can make the formation of isochromene structure. In order to synthesize isochromene structure, we used aldehydes as starting material, synthesis design was carried out using three steps, firstly we use Henry reaction, then using Wacker-type oxidation, and finally K2CO3-promoted intramolecular Michael cyclization successfully synthesis isochromene structure.
Ding, Chun-Feng, und 丁群峰. „Organocatalytic Michael-Knoevenagel-Hetero-Diels-Alder Reaction to Isochromene Pyrimidinedione derivatives“. Thesis, 2012. http://ndltd.ncl.edu.tw/handle/6weet9.
Der volle Inhalt der Quelle國立中正大學
化學暨生物化學研究所
100
Utilization of α,β-unsaturated aldehydes, olefin nitroalkanes and 1,3-dimethylbarbuturic acid undergo organocatalytic Michael-Knoevenagel-Hetero-Diels-Alder reaction via the one pot multicomponent strategy to synthesis isochromene pyrimidinedione derivatives with excellent diastereoselectivity and enantioselectivity. The structure of product was confirmed by X-ray and NMR analysis.
Sing, Shen, und 沈昕. „Gold-Catalyzed Cyclization ofbenzyl 2-(phenylethynyl)benzoate.Synthesis ofisocoumarins and 4-benzyl-3-phenyl-1H-isochromen-1-ones“. Thesis, 2016. http://ndltd.ncl.edu.tw/handle/80080110324135857351.
Der volle Inhalt der Quelle國立中山大學
化學系研究所
104
In this research, a new method was discovered to selectively obtain cyclic product under gold catalyst and silver co-catalyst or other co-catalyst. Using 4-methoxybenzyl 2-(phenylethynyl)benzoate and their deriviatives under gold and co-catalyst catalyzed in different solvent at 80 oC to get cyclic product 3-phenyl-1H-isochromen-1-one (isocoumarin), and the 4-(4-methoxybenzyl)-3-phenyl-1H-isochromen-1-one also can be obtain in the same time.
Karapetyan, Vahuni [Verfasser]. „Synthesis of bridged and non-bridged N-heterocycles, dichloromethyl- and formyl-salicylates, pyran-4-ones, chromanes and isochromanes based on cyclocondensation reactions of 1,3-bis(silyloxy)-1,3-butadienes and oxime dianions / vorgelegt von Vahuni Karapetyan“. 2009. http://d-nb.info/1001599659/34.
Der volle Inhalt der QuelleGorgoi, Mihaela. „Electronic Properties of Phthalocyanines Deposited on H-Si(111)“. Doctoral thesis, 2005. https://monarch.qucosa.de/id/qucosa%3A18667.
Der volle Inhalt der QuelleIn the context of this work four Phthalocyanine were studied: Metal-free Phthalocyanine (H2Pc), Copper Phthalocyanine (CuPc) and fluorine-substituted Phthalocyanine (F4CuPc and F16CuPc). The goal of this work is the electronic and chemical characteristics of the interfaces. The molecules were deposited by organic molecular beam deposition (OMBD) in the ultra high vacuum on hydrogen-passivated Si(111)-Substrate. Surface sensitive techniques such as photoemission spectroscopy (PES), bremsstrahlung isochromate spectroscopy (BIS or IPES - inverse photoemission spectroscopy) and near edge X-ray absorption fine structure spectroscopy (NEXAFS) were used for characterisation. Theoretical computations by density functional theory methods were employed, in order to assign different components in PES and IPES. The energy level alignment at the organic/H-Si interface, as well as the transport gap of H2Pc, CuPc, F4CuPc and F16CuPc were determined by PES and IPES. The NEXAFS measurements determine the exact molecular orientation with respect to the substrate. The evaluation of the data showed different molecular orientation in the thin and thick films. This change was correlated with the band bending like behaviours that emerged at these interfaces. In addition to the band bending like behaviour, the interfaces show also an interface dipole which is driven by the work function difference between the contact materials. The influence of the degree of fluorination is confirmed in the similar increase of the EA, WF and IE. The electronic properties of metal/organic layer interfaces and of organic layer under oxygen influence were examined by PES and IPES. The Ag/Pc interfaces show a mixture of HOMO-LUMO shifts and interface dipole formation. A charge transfer complex is formed in the case of Ag/H2Pc and Ag/F16CuPc interfaces. Ag is physisorbed atop the CuPc. Charge transfers from F4CuPc to Ag creating a continuous n-type doping at the interface. Similar to the Pc/H-Si interfaces the interface dipoles found here show a linear dependence on the EA, WF and IE and can be predicted by the difference in the work functions. The data evaluation of oxygen exposed thick films determined two groups of behaviours. The weak interaction group is represented by H2Pc and F4CuPc, Pcs on which oxygen is physisorbed. The strong interaction group contains the other two molecules CuPc and F16CuPc. CuPc forms a charge transfer complex with oxygen and on top of F16CuPc a polarized layer is formed.
Li, Liao. „Chemical Forays of Fungal Metabolites“. Phd thesis, 2018. http://hdl.handle.net/1885/148782.
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