Dissertations / Theses: 'Pinacois'

1

Valla, Carine Sandrine Stephanie. "Pinacol coupling using catalytic samarium (II)." Thesis, University of Liverpool, 2003. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.288128.

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2

Liu, Zenghui. "I. On the Mechanism of Acid Promoted Rearrangement of PCU-Derived Pinacols II. Synthesis of a Trimethyltrishomocubyl Helical Tubuland Diol." Thesis, University of North Texas, 1995. https://digital.library.unt.edu/ark:/67531/metadc277859/.

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I. Reductive dimerization of pentacyclo[5.4.0.0.^2,6.0^3,10.0^5'9]undecane-8-one-(PCU-8-one, 53) affords a mixture of meso and d,l pinacols (55a and 55b respectively). Acid promoted rearrangement of 55a and 55b conceivably can proceed with migration of C(7)-C(8) and/or C(8)-C(9) to form the corresponding pinacolone(s). In our hands, acid promoted rearrangement of 55a and 55b each proceeds with exclusive migration of C(7)- C(8) bond, thereby affording 58a and 59a respectively. Mechanistic features of this rearrangement are discussed. II. 4,7,1 l-trimethylpentacyclo[6.3.0.0.^2,6.0^3,l0.0^5,9]undecane-exo-4,exo-7-diol (23a) was successfully synthesized. This diol crystallizes in a helical tubuland lattice although its molecular structure does not possess C2 rotational symmetry.

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3

JAZOULI, MOHAMMED. "Cycloadditions dipolaires-1,3 avec les vinylboronates derives du pinacol." Rennes 1, 1991. http://www.theses.fr/1991REN10039.

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Ce memoire decrit la reactivite de vinyl boronate derive du pinacol vis-a-vis des diazocomposes, des oxydes de nitriles et de nitrones avec les diazocomposes le mecanisme d'evolution du produit primaire de cycloaddition est etudie. L'evolution du cycloadduit est precisee: boratropie 1,3 puis rupture eventuelle de la liaison n-b et obtention de 2-pyrazolines quelquefois difficile a obtenir par d'autres voies. Les tentatives de synthese de cyclopropanes boryles qui auraient constitue des intermediaires de synthese tres interessants ont echoue. Les oxydes de nitriles sont d'excellents dipoles et conduit a des isoxazolines boronates. Leur reactivite n'a pas ete systematiquement etudiee mais ces composes presentent des potentialites synthetiques. Obtention d'hydroxyisoxasolines, d'isoxazoles, des cetoboronates. Une etude plus approfondie des possibilites offertes par ces composes est necessaire. Enfin, il est montre que les nitrones sont de mediocres dipoles vis-a-vis du vinyl boronate derive du pinacol a l'exception de la c-benzoyl n-phenylnitrone. Dans ce dernier cas, les proprietes chimiques de l'adduit ne sont pas etudiees. Enfin le travail effectue met en evidence les proprietes oxydantes des nitrones deja connues, mais qui necessiteraient d'etre plus systematiquement etudiees

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4

Blanc, Guilaine F. "New strategies for pinacol cross-couplings and alkenation reactions." Thesis, University of Glasgow, 2010. http://theses.gla.ac.uk/2227/.

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The research described herein involves the study of new approaches to alkenation and pinacol cross-coupling. The competition between modified Julia alkenation and Peterson alkenation was studied. Heterocyclic sulfides were oxidised to sulfones by dimethyldioxirane. Reactions between sulfones and aldehydes gave vinyl sulfones in good yields, rather than vinyl silanes, confirming that the Peterson alkenation is preferred in this system. Pinacol cross-coupling between an aldehyde or ketone in solution and a more easily reduced aldehyde immobilised on resin was attempted, but proved unsuccessful. However, aldehydes bearing the salts of tertiary amines were found to be good substrates for pinacol homo-coupling giving diols. The formation of salt avoided unwanted reduction of the aldehyde to a primary alcohol. A wide range of approaches to anisomycin using titanium reagents were investigated. These were based on the formation of the bond between C-3 and C-4 by alkylidenation of esters and ring-closing metathesis (RCM) or intramolecular alkylidenation or radical cyclization. The presence and position of the nitrogen atom proved an insurmountable obstacle to this strategy. The solid-phase synthesis of 4-amino-ketones was achieved. Resin-bound esters were alkylidenated using a novel titanium reagent generated in situ by reduction of a thioacetal with a low valent titanium reagent. Treating the resulting enol ethers with acid gave ketones in good yield and high purity because of the switch in the nature of the linker from acid-stable to acid-sensitive (a chameleon catch strategy). Amino-ketones are potential precursors of pyrrolidines.

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Àvila, Genís. "Geometria i forma dels pinacles de la Sagrada Família, d’Antoni Gaudí." Doctoral thesis, Universitat Politècnica de Catalunya, 2015. http://hdl.handle.net/10803/311443.

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Based on the study and analysis of existing buildings, and using three-dimensional modeling software, we can understand and thus explain the main mechanisms for historic buildings design and construction, making them understandable to non-specialist audiences. Knowledge of CAD softwares devices allow us a deeper study of the development of mechanisms that describe the building before constructing it or when we have to rebuild them into their original state if they have been destroyed or partially sunk. The thesis explores these resources from various examples from Antoni Gaudí works, Catalonia's most influent architect, with special emphasis on the geometry and the form that defines it. The level of expertise achieved and the constant process of training gives us the capacity to transmit (to future generations) resources in order to achieve with judgment and utmost accurary the necessary documentation to be good professionals in the field of design,engineering and architecture.
A partir de l'estudi i anàlisi d'edificis existents ,i utilitzant el modelat tridimensional hom pot entendre i per tant explicar, els principals mecanismes de disseny i construcció d'edificis històrics fent-los comprensibles a públics no especialitzats. El coneixement de les eines que ens ofereixen avui els softwares de CAD permeten aprofundir molt en el desenvolupament de mecanismes descriptius de l'edifici, abans de construir-los o tornant-los al seu estat originari si han sigut enfonsats o parcialment enfonsats. La tesi aprofundeix en aquests recursos a partir de diversos exemples, obres d'Antoni Gaudí, arquitecte referent a Catalunya, incidint especialment en la geometria i en la forma que els defineix. El grau d'expertesa assolit i el constant procés de formació ens doten de capacitat per transmetre (a futures generacions) recursos per tal d'assolir amb criteri i rigor la documentació necessària pera ser bons professionals en el camp del disseny, l'enginyeria i l'arquitectura.

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6

Kachala, Manpreet S. "A pinacol coupling approach to N-heterocycles : synthesis of iminosugars." Thesis, University of Leicester, 2003. http://hdl.handle.net/2381/30081.

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A series of 5-8 membered N-heterocyclic diols have been prepared from dicarbonyls (shown below), via intramolecular pinacol reactions. The cis- or trans-stereoselectivity of these reactions is controlled by judicious choice of the low-valent metal reagent employed. The diastereoselectivity of the pinacol products is pleasingly comparable with literature examples, albeit with lower levels of stereocontrol in some cases than the corresponding carbocyclic systems. Deprotection to yield the corresponding novel amino diols has also been undertaken so that biological testing could be performed. (Fig. 10988).;In addition a novel reaction has been developed whereby an ozonide precursor is treated with SmI2 to carry out both ozonide reduction and pinacol coupling in the same pot to yield the corresponding -heterocyclic diol.;Trihydroxypiperidines, such as 1,5-dideoxy-1,5-imino-arabinitol have been synthesised in order to investigate and explain the 'directing' effects alpha-alkoxy substituents have on the stereoselectivity of the pinacol reaction. The levels of stereoselectivity of the reaction were good, but lower that the comparable carbocyclic cases. To the best of our knowledge we have also carried out the first titanium-mediated (Cp 2TiPh) pinacol coupling of an alpha-alkoxy substituted dicarbonyl which proceeds with a good level of diastereoselectivity.;Ring-closing metathesis with Grubb's catalyst and dihydroxylation with osmium tetroxide reactions have been applied as an alternative method for the synthesis of a series 6- and 7-membered of N-heterocycles. These products were compared to the products synthesised via pinacol coupling reactions to confirm their stereochemistry.

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7

Smith, Zoe Ann. "A pinacol coupling approach towards the synthesis of 3,4-pyrrolidine-diols." Thesis, University of Leicester, 2004. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.409371.

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8

Lavigne, Roch M. A. "Prins-pinacol synthesis of a variety of highly functionalized bicyclo[4n1]alkanones." Thesis, University of Ottawa (Canada), 2006. http://hdl.handle.net/10393/27385.

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Bridged ring cores possessing quaternary carbon centers adjacent to a bridged ketone constitute challenging structures in synthesis. Therefore, this thesis explores the development of the first Prins-pinacol synthesis of cis-fused bicyclo[4,n,1]alkanones. The reaction conditions were optimized for the rearrangement of bicyclo[4.4.0]decanes and the effect of different diol protecting groups was explored, as well as the effect of substitution at the C4 and the C5 position. The rearrangement of bicyclo[5.4.0]undecane and bicyclo[5.3.0]decanes was also investigated in order to achieve the formation of bicyclic ketones with various ring sizes. Finally, the Prins-pinacol rearrangement was coupled with an ionic Diels-Alder reaction in order to achieve the rapid synthesis of highly functionalized polycyclic bridgehead ketones.

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9

Pena, Paula Cristina de Aguiar. "Semi-pinacol rearrangements of epoxy tertiary alcohols derived using poly-L-leucine methodology." Thesis, University of Liverpool, 2003. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.272797.

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10

Schirmann, Jéseka Gabriela. "Estudo visando a síntese do terreinol através da reação de acoplamento pinacol cruzada." Universidade Estadual de Londrina. Centro de Ciências Exatas. Programa de Pós-Graduação em Química, 2012. http://www.bibliotecadigital.uel.br/document/?code=vtls000178937.

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O terreinol é um metabólito secundário isolado de culturas de Aspergillus terreus. Em virtude de sua estrutura pouco comum e pelo interesse em investigar sua bioatividade, propomos neste trabalho, uma nova rota de síntese para este produto natural. A estratégia sintética baseia-se na reação de acoplamento pinacol cruzada entre aldeídos eletronicamente distintos mediados por vanádio (II). Este trabalho descreve a síntese de substratos aromáticos modelo (A e 16) para a avaliação da sua eficiência para se acoplar com os aldeídos alifáticos 4-6. O 4-benziloxi-butanal (4) e o 3,5-dimetoxibenzaldeído (A), foram obtidos com 57% (2 etapas) e 29% (4 etapas) de rendimento global, respectivamente. A obtenção do aduto de homoacoplamento na reação de pinacol cruzada entre estes componentes carbonílicos sugere uma reatividade inconvenientemente alta para o componente alifático, possivelmente devido à quelação do oxigênio do grupo benzila com o centro de vanádio. Visando evitar a quelação, outros dois aldeídos alifáticos, 5 e 6, foram sintetizados em duas etapas a partir do 1,4-butanodiol com 27% e 34% de rendimento global, respectivamente. Além disso, um aldeído aromático tetrassubstituído particularmente ativado, o 2-benziloximetil-3,5-dimetoxibenzaldeído (16), sintetizado em 7 etapas (15%) foi empregado. No entanto, a reação de acoplamento de pinacol cruzada entre os aldeídos 6 e 16 mostrou-se lenta e forneceu uma mistura complexa de produtos de decomposição dos aldeídos de partida. Isto pode indicar a existência de características eletrônicas e/ou estéricas adicionais desfavoráveis ao acoplamento cuja elucidação requer um estudo mais detalhado.
Terreinol is a natural product isolated from Aspergillus terreus. Due to its unique structure and our interest in evaluate its bioactivity, we propose herein a novel synthetic route toward this compound. Our synthetic approach is based on the V (II)-mediated pinacol cross coupling reaction between two electronically distinct aldehydes. This study describes the synthesis of model aromatic substrates (A e 16) to be evaluated with respect to their efficiency in coupling to the aliphatic aldehyes 4-6. Therefore, 4-benzyloxy-butanal (4) and 3,5-dimethoxybenzaldehyde (A) were obtained with 57% (2 steps) and 29% (4 steps) respectively. The formation of homocoupling adducts in the pinacol reaction of these aldehydes suggests a reactivity inconveniently high of the aliphatic component, possibly due to quelation of OBn oxygen atom to the vanadium center. Aiming at the inhibition of quelation, two other aliphatic aldehydes, 5 and 6, were synthesized (two steps from 1,4-butanediol, 27% and 34% global yield, respectively. Besides, a particularly activated tetrasubstituted aromatic aldehyde 16 (obtained in 7 steps, 15%) was used. Nevertheless, the pinacol cross coupling between aldehydes 6 e 16 showed to be slow and furnished a complex mixture of byproducts majorly constituted of decomposition compounds from starting materials. These information indicate the actuation of additional unfavorable electronic and/or steric characteristics that could inhibit the cross coupling. Further studies are crucial to elucidate these propositions.

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11

Vinicius, Pereira dos Santos Marcus. "Dinâmica direta e mecanismos das reações de Diels-Alder e de desidratação de álcool." Universidade Federal de Pernambuco, 2008. https://repositorio.ufpe.br/handle/123456789/8384.

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A dinâmica de desidratação do isômero (R)-3,3-dimetilbutan-2-ol (pinacolil protonado), [(CH3)3-C-CH(OH2)CH3]+, e de cicloadição do eteno com 1,3-butadieno foram estudadas com a dinâmica molecular de Born-Oppenheimer (BOMD) utilizando o método AM1. A superfície de energia potencial AM1 para o álcool protonado apresenta dois estados de transição relacionados ao intermediário [(CH3)3C-CHCH3]+ OH2 e para a migração do CH3 levando ao produto [(CH3)2C-CH(CH3)2]+ OH2 ambos nas formas ligadas ou complexos (interação cátion-água e ligação de hidrogênio). A dinâmica direta produziu um número desprezível de trajetórias envolvendo estes complexos, desde que o momento adquirido pelo fragmento H2O leva à completa dissociação. Apesar do caminho concertado (dissociação de H2O e migração do CH3 simultaneamente) não ser o caminho de mínima energia (ou IRC do inglês Intrinsic Reaction Coordinate) na superfície AM1 um número estatisticamente signiﬁcativo de trajetórias envolveram este caminho. Assim como para a reação de Diels-Alder, que mesmo quando iniciada em um estado de transição simétrico utilizando função de onda AM1 com restrição de spin, a dinâmica produz uma grande percentagem de caminhos assimétricos em direção ao ciclohexeno. Logo em ambas as reações, as dinâmicas revelaram signiﬁcativos caminhos de reação do tipo não-IRC

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12

Fontaine, Laurent. "Altération microbienne de l'apatite et de l'orthoclase chez les Pinaceae." Master's thesis, Université Laval, 2016. http://hdl.handle.net/20.500.11794/26697.

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Dans la forêt boréale, l'activité des microorganismes de la mycorhizosphère peut jouer un rôle important dans la nutrition des plantes et dans le développement de l'écosystème et des cycles biogéochimiques par l'altération des minéraux. Dans la présente étude, quelques champignons ectomycorhiziens (ECM) communément associés aux Pinacées ont été mis à l’épreuve en conditions in vitro pour démontrer leur capacité à dissoudre la fluorapatite, un phosphate de calcium, et l’orthoclase, un feldspath potassique. Ces minéraux ont été dissouts par les souches ECM sélectionnées et certaines ont montré une croissance significativement plus grande par rapport aux témoins sans phosphore ou potassium lorsque ces nutriments étaient disponibles sous forme de minerai. La présence de bactéries solubilisatrices de minéraux phosphatés (BSP) a été confirmée dans la mycorhizosphère de Picea glauca. Quatre cent cinquante-cinq souches solubilisant le phosphate tricalcique ont été isolées d’ectomycorhizes de l’ascomycète ECM Wilcoxina sp., lequel dominait la communauté ECM d’un peuplement de P. glauca. Parmi ces centaines d’isolats, vingt-sept d’entre eux étaient aptes à dissoudre la fluorapatite. Des études ultrastructurales ont montré la capacité de ces bactéries BSP à dissoudre complètement des cristaux de fluorapatite en moins d’une journée. Ces mêmes bactéries BSP s’associent avec le champignon ECM Laccaria bicolor en conditions oligotrophiques. Les colonies de BSP présentaient un diamètre significativement plus élevé lorsque le basidiomycète ECM L. bicolor était contraint d’alimenter les bactéries pour obtenir son phosphore d’une source insoluble. Ces résultats supportent le modèle de l’association tripartite «plante-champignon-bactérie» qui expliquerait la mise en disponibilité des nutriments à partir du sol minéral en forêt boréale.
In boreal forests, mycorrhizospheric microorganisms can play an important role in plant nutrition, ecosystem development and biogeochemical cycles through mineral weathering. In this study, a few ectomycorrhizal (ECM) fungal species commonly found in association with Pinaceae were tested in vitro for their ability to weather fluorapatite, a calcium phosphate, and orthoclase, a potassium feldspar. These minerals were dissolved by the selected ECM strains and some of them produced significantly greater biomasses when supplied with the above-mentioned minerals as opposed to controls lacking phosphorus or potassium. The presence of phosphate solubilising bacteria (PSB) has been confirmed in the mycorrhizosphere of Picea glauca. Four hundred fifty-five strains solubilising tricalcium phosphate were isolated from the ECM Ascomycete Wilcoxina sp., which dominated the ECM community of a P. glauca stand. Among these isolates, twenty-seven dissolved fluorapatite. Ultrastructural studies revealed the ability of the PSB to completely dissolve fluorapatite crystals within a day. The same bacteria associated with the ECM fungus Laccaria bicolor in oligotrophic conditions. The PSB colonies displayed significantly greater diameters when the Basidiomycete L. bicolor was forced to sustain their growth in order to obtain phosphorus from an insoluble source. These results support the model of tripartite association among trees, ECM fungi and bacteria which seeks to explain the mobilization of nutrients from mineral soil in boreal forests.

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13

Hao, Xiang. "STUDIES OF UNUSUAL PACKING AND OF POLYMORPHISM IN TWO CRYSTAL SYSTEMS." UKnowledge, 2005. http://uknowledge.uky.edu/gradschool_diss/285.

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Crystal structures of anhydrous pinacol, the hexagonal pinacol, pinacol monohydrate, and pinacol hexahydrate were studied. In all the structures crystal packing is unusual and complicated. The origin of the complexity may be the difficulty in filling space densely and while also satisfying the H-bonding requirements when the molecule has few internal degrees of freedom. Five 15-crown-5 complexes of M(NO3)2 (M = Cu, Zn, Mg, Co, Mn) were synthesized and characterized using X-ray diffraction and differential scanning calorimetry. The system is rich in polymorphs. Nine definite solid-state phases were identified. More phases probably exist in the solid state at temperatures slightly above the room temperature. Most phase transformations in this system take place in single crystals without the loss of crystallinity. The nine phases crystallize in five crystal structures. The crown ether ligands have very similar conformation in all the structures. The asymmetric units in all the structures are complicated and pseudosymmetric, which is the consequence of the presence of the packing problem. The origin of the packing problem that leads to the complicated phase behavior is the odd number of -CH2-O-CH2- units in the crown ether ligand.

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14

Al, Batal Mona [Verfasser]. "The aryl approach to the synthesis of eunicellane-type diterpenoids: samarium- and titanium-mediated pinacol cyclizations / Mona Al Batal." München : Verlag Dr. Hut, 2013. http://d-nb.info/1033041793/34.

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15

Pelgas, Betty. "Cartographie génétique comparative chez les Picea et autres pinaceae." Thesis, Université Laval, 2006. http://www.theses.ulaval.ca/2006/24131/24131.pdf.

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16

Hilmey, David George. "Synthesis and study of heteroatomic spirocyclic scaffolds." Columbus, Ohio : Ohio State University, 2006. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=osu1141334542.

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17

Bailly, Lucile. "Caractérisation moléculaire et isotopique de goudrons et résines archéologiques dérivés de conifères en contexte maritime." Thesis, Strasbourg, 2015. http://www.theses.fr/2015STRAF013/document.

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De tous temps, les Pinacées ont été utilisés pour leur résine ou le goudron que l’on peut en tirer, principalement dans le domaine maritime (calfatage, protection des cordages) et pour le poissage d’amphores. Ces travaux ont été consacrés au développement de nouveaux outils moléculaires et isotopiques pour la caractérisation de tels matériaux trouvés en contexte archéologique (distinction goudron / résine, origine taxonomique et géographique, modes de fabrication). Sur la base des outils développés, il apparait que l’utilisation de goudron prévaut dans ce contexte sur celle de résine et que les Pinus, dont les espèces peuvent être partiellement discriminées, sont les principaux Pinacées utilisés. Il a aussi pu être montré que les matériaux de calfatage et d’enduits de cordages sont globalement issus d’une cuisson moins poussée que ceux utilisés dans le poissage de récipients. Une distinction des échantillons archéologiques sur la base de leur composition isotopique en D a été proposée
Resins and tars of Pinaceae have been used in the past mainly in the maritime field (caulking, protection of the ropes) and for the waterproofing of jars and amphorae. This study was devoted to the development of new molecular and isotopic tools for the characterization of such materials found in archaeological context (discrimination between tar / resin, taxonomic and geographical origin, manufacturing methods). Based on the detailed molecular and isotopic investigation of diterpenic compounds, in particular, it appears that the use of tar prevails in this context over that of resin and that trees from the genus Pinus, which can be partially discriminated in terms of species, have been preferentially used. It could be shown that the caulking material and the tar protecting ropes result overall from a less intense heating process than the material used to waterproof containers. A distinction of the archaeological samples on the basis of their isotopic composition in D was proposed

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Vourc'h, Gwenaël. "Interactions entre plantes longévives et grands mammifères : défense chimique du thuya géant et herbivorie par le cerf-à-queue-noire en Colombie Britannique (Canada)." Montpellier 2, 2001. http://www.theses.fr/2001MON20189.

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19

Liang, Tao. "Chiral Phosphoric Acids and Alkaline Earth Metal Phosphates Chemistry." Thesis, University of South Florida, 2014. http://pqdtopen.proquest.com/#viewpdf?dispub=3632228.

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Asymmetric synthesis and catalysis is one of the leading research areas in chemistry society, for its versatility and efficiency in obtaining chiral molecules that found the vast majority in natural active compounds and synthetic drugs. Developing asymmetric catalytic methodology is at the frontier in both industrial and academic research laboratories. Enantioselective organocatalysis has emerged as a powerful synthetic tool that is complementary to metal-catalyzed transformations. The development of chiral phosphoric acid and metal phosphate as catalysts has been a breakthrough in recent years. Chiral phosphoric acids have been shown to be powerful catalysts in many organic transformations. Moreover, chiral metal phosphates, which formed by simply replacing the proton in phosphoric acid with metals, have introduced new catalytic activations and broaden the scope of phosphoric acids. This thesis details new highly enantioselective chiral phosphoric acid-catalyzed Pinacol rearrangement and robust alkaline phosphates catalytic system, which utilizes novel carbonyl activation.

The Pinacol rearrangement has long been known to be difficult to control in terms of regioselectivity and stereoselectivity. The initial studies found that indolyl-diol compounds can be treated with chiral phosphoric acids to afford the Pinacol rearrangement with high regio- and enantioselectivity. Over 16 chiral phosphoric acids were screened, and it was found an H8-BINOL-phosphoric acid variant with 1-naphthyl groups at 3 and 3' position was the excellent catalyst. This asymmetric transformation is tolerant toward variety of substituents both on the indole ring and migrating groups.

During the study, it was found that different ways to generate the catalyst had critical effect on this catalytic transformation. Only those phosphoric acids washed with HCl after column chromatography afforded the rearrangement products with high enantioselectivity. And those without treating with HCl were found contaminated by alkaline metals. These "contamination" catalysts were also found active with carbonyl activations.

A highly enantioselective catalytic hetero-Diels-Alder reaction of alpha-keto esters has been developed with chiral alkaline metal phosphates. A calcium 1-naphthyl-BINOL phosphate was found to be the optimum catalyst. A large range of alpha-keto esters as well as isatins can be applied in this alkaline phosphates catalytic system with high efficiency and selectivity. The structure of the catalyst is detailed for the first time by X-ray crystal structure analysis. A proposed Transition state model is provided based on the catalyst crystal structure and Raman spectroscopy analysis.

This methodology was further developed with an asymmetric Mukaiyama-Michael addition of beta,gamma-unsaturated alpha-keto ester. The best catalyst was found to be a magnesium chiral phosphate. And the transformation was found capable of tolerating a wide variety of beta,gamma-unsaturated alpha-keto esters.

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Imbs, Claire. "Synthèses éco-compatibles de nouveaux fongicides par chimie radicalaire." Thesis, Compiègne, 2018. http://www.theses.fr/2018COMP2457/document.

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Les travaux de recherche présentés ici ont pour objectif la synthèse de fongicides innovants de la manière la plus éco-compatible qu’il soit. Pour cela, plusieurs axes de réflexion ont été étudiés. Tout d’abord, la synthèse d’un intermédiaire de fongicides bien connu, l’o-crésol1, a été réalisée à partir d’un substrat naturel, le salicylaldéhyde2. Les conditions expérimentales ont été éco-conçues afin de correspondre au mieux aux exigences de la chimie verte. Des solvants et des réactifs classés verts ont été utilisés, comme l’éthanol, l’eau et l’acide acétique3 par exemple, ainsi que des techniques alternatives comme l’activation par micro-ondes (Schéma 1). Dans un second temps, des synthèses éco-compatibles de nouveaux fongicides ont été réalisées. Le salicylaldéhyde, substrat naturel de référence, a été mis à réagir avec différents alcools afin de réaliser des réactions d’éthérifications réductrices. Les molécules obtenues sont composées d’une partie phénolique portant un groupement alcoxyle en position 2. Ce groupement alcoxyle se compose d’une longueur de chaîne variable ayant une influence sur les propriétés fongicides des produits synthétisés (Schéma 1). Troisièmement, des réactions d’homo- et d’hétéro-couplages pinacoliques ont été réalisées entre divers aldéhydes, aromatiques et aliphatiques, afin d’obtenir des diols vicinaux, appelés pinacols, symétriques ou non (Schéma 1). Dernièrement, les propriétés fongicides et anti-oxydantes de toutes les molécules obtenues de manière stable, référencées ou non, ainsi que les substrats de départ, ont été testés. Les tests microbiologiques ont été réalisés sur une gamme de diverses souches fongiques
The purpose of this research is to synthesize innovative fungicides by the most ecocompatible way. Several hypotheses have been investigated. First, an extensively studied molecule, intermediate of fungicides, o-cresol1, has been achieved from a natural substrate, salicylaldehyde2. The experimental conditions have been eco-designed in the aim to best match green chemistry requirements. Green solvents and reactants have been used, as ethanol, water and acetic acid3 for example, as well as alternative technologies like microwaves activation (Schema 1). Secondly, novel fungicides green syntheses have been carried out. Salicylaldehyde, a natural substrate model, reacted with various alcohols in the aim to perform reductive etherification reactions. In this way, products were composed of phenolic part with an alkoxyl group at the 2nd position. These alcoxyl groups have various chain lengths, playing a key role in fungicidal ability (Schema 1). Then, homo and hetero pinacol coupling reactions have been achieved with various aromatic or aliphatic aldehydes to obtain symmetrical and asymmetrical vicinal diols, called pinacols (Schema 1). At last, fungidal and antioxidant properties of all stable obtained molecules, referenced or not, as well as starting materials, have been evaluated. Microbiological studies have been carried out with various fungal strains

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21

Lamy, Jean-Baptiste. "Résistance à la cavitation : des mécanismes physiologiques à la génétique évolutive : de la bulle aux gènes." Thesis, Bordeaux 1, 2012. http://www.theses.fr/2012BOR14499/document.

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Force est de constater que les dépérissements forestiers augmentent. Ces observations vont de pairs avec l’accroissement des événements climatiques extrêmes. Aussi dans ce contexte, il est nécessaire d’identifier denouveaux caractères de resistance à la sécheresse. La résistance à la cavitation est actuellement le meilleurmarqueur de la survie d’une espèce à la sécheresse.Cette thèse avait deux objectifs : (i) comprendre le mécanisme de propagation de la cavitation dans le xylèmechez les gymnospermes. (ii) Quantifier la variation phénotypique in situ de ce caractère chez Pinus pinaster ainsique (iii) quantifier la variation génétique, et sa plasticité phénotypique.La démarché a été la suivante (i) une étude interspécifique de la résistance à la cavitation a été couplé à desmesures micro-anatomiques. (ii) Pour le volet intraspécifique, nous avons phénotypé 6 populations dans deuxtest de populations-descendances, ainsi qu’en population naturelles in situ.La propagation de l’embolie chez les Pinaceae et les ex-Taxodiaceae pourrait être due au passage du germe d’air(rupture capillaire) à travers des nanopores dans le torus. En effet, la pression de rupture d’un ménisque air-sèveest corrélée à l’entrée de l’air dans le xylème (P12). Alors que la variation interspécifique est grande, la résistanceà la cavitation varie faiblement au sein d’une espèce. Ainsi les populations provenant de climat contrasté neprésentent pas ou peu de différence génétique (en test de provenance) ou en populations naturelles in situ. Cecaractère présente une plasticité phénotypique mais faible comparée à celle de la croissance en hauteur parexemple. La comparaison entre la variation génétique entre populations et la variation des marqueurs neutresentre ces mêmes populations montrent que la variation de ce caractère semble réduite par l’architecturegénétique sous-jacente. La resistance à la cavitation est vraisemblablement un trait canalisé
Several review reported global forest die-back that are caused, directly or indirectly, by extreme climatic events(like heat waves or prolonged drought). In this context, there is an urgent need to identify new traits to tracedrought tolerance. Resistance to cavitation is one of the best proxy for survival during extreme drought.The aim of this work was (i) to understand how spreads cavitation in the vascular pathway of gymnosperms (ii)to quantify the phenotypic variation of resistance to cavitation for Pinus pinaster species, (iii) to determine theamount of the genetic variation and phenotypic plasticity available for this trait.A micro-anatomy study was coupled to measurement of resistance to cavitation for various species to foundwhere air-seeding occurs in the bordered pit. To quantify the variability of resistance to cavitation, wephenotyped 506 genotypes using to replicated provenance-progeny trials and on natural in situ populations.The spread of embolism for Pinaceae and ex-Taxodiaceae could be due to minute pore in tori, which are remainsof secondary plasmodesmata. We found that the pressure needed to break a water/air meniscus in these minutepores is correlated with the xylem air entry (P12). Despite the great variability of resistance to cavitation betweenspecies, we found low variability within species. Most of the variability is within population, rather than betweenpopulations. The phenotypic plasticity of resistance to cavitation is low compare to growth traits. Comparisonbetween QST and FST shows that populations exhibit less variation compare to what it is expected under geneticdrift. The variation of resistance to cavitation seems to be narrowed by the genetic architecture, which is the signof canalisation

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22

Morris, John W. "Efficient transformation of pinaceous gymnosperm cells by Agrobacterium /." 1990. http://hdl.handle.net/1957/11200.

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23

劉文莊. "Factors Affecting Employee Loyalty at PINACO, Vietnam." Thesis, 2016. http://ndltd.ncl.edu.tw/handle/7887ha.

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碩士
美和科技大學
企業管理系經營管理碩士班
104
With the intention to help the company to maintain and develop the strong workforce, especially among the office staff in the condition of fierce competition from other companies and the narrowing down of the activities of the battery and cell company, the author carried out this research. From the theory about motivation and previous studies, the author put forward the research framework with six hypotheses, including a positive relationship between salary, work environment, colleagues, rewards, welfares, training and promotion opportunities with employee loyalty. The research was conducted by both qualitative and quantitative method with the participation of 237 respondents. After analyzing the data using SPPS 16.0, the author found that all hypotheses are supported. Based on this, some suggestions are pointed out to help to company develop the labor force and attract more talented peoples.

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24

Hsieh, Michelle, and 謝秀琴. "Pinacol-type rearrangement catalyzed by iron-substituted molecular sieves." Thesis, 2000. http://ndltd.ncl.edu.tw/handle/21006261140254100102.

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碩士
國立臺灣大學
化學研究所
88
This thesis studied pinacol-type rearrangement reactions catalyzed by iron-substituted molecular sieves of various pore structures, including AlPO4-5, ZSM-5 and MCM-41. The pore diameters of these three molecular sieves were about 0.75, 0.55 and 2.6 nm, respectively. By using toluene as solvent, iron (III) substituted in the framework of the molecular sieves was found to be the active center of pinacol rearrangement reaction. Ten diol reactants of various alkyl or aryl substitution were examined. The results showed that AlPO4-5 molecular sieve containing 0.5~2%Fe was most active in catalyzing the pinacol rearrangement of 2,3-dimethylbutanediol. On the other hand, Fe-substituted MCM-41 was most active in catalyzing the rearrangement of large molecules such as 2,3-pinanediol and 2,3-diphenyl-1,2-ethanediol. All these molecular sieves were not catalytic active in the rearrangement of the diol compounds of high polarity. That was attributed to that the polar molecules would cover the catalyst surfaces and deactive the catalysts. The rearrangement reaction proceeded very easily for one aryl substituted diol even without the catalysts because of the thermally stable benzylic cation formed as the intermediate. The substitution groups migrating priority decreases in order of aryl > hydrogen > alkyl, that is similar to what observed on acid-catalyzed reactions.

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Chen, Te-Hsuan, and 陳德瑄. "Palladium-Catalyzed Oxidative Coupling Reaction of H-phosphonates with Aryl Pinacol Boronates." Thesis, 2017. http://ndltd.ncl.edu.tw/handle/11237891970303489306.

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Mladenova, Gabriela. "Molecular rearrangements of photolytically generated carbocations." 2001. http://wwwlib.umi.com/cr/yorku/fullcit?pMQ71609.

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Thesis (M. Sc.)--York University, 2001. Graduate Programme in Chemistry.
Typescript. Includes bibliographical references (leaves 85-90). Also available on the Internet. MODE OF ACCESS via web browser by entering the following URL: http://wwwlib.umi.com/cr/yorku/fullcit?pMQ71609.

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27

Chen, Yong Ren, and 陳鏞任. "Development of radiofluorofenbufen boron pinacol and radiofluorocelecoxib analogs for positron emission tomography and boron neutron capture therapy." Thesis, 2015. http://ndltd.ncl.edu.tw/handle/suumzu.

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28

Luo, Yue-Gui, and 羅月貴. "Palladium-Catalyzed Cyclization and Oxidative Cross-Coupling Reaction of N,N-Dimethyl-2-(phenylethynyl)aniline with Aryl Pinacol Boronates." Thesis, 2018. http://ndltd.ncl.edu.tw/handle/tx9zu4.

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碩士
國立中興大學
化學系所
106
This thesis is about synthesis of indole derivatives, which has found in many bioactive natural products, medicinal chemistry, materials chemistry, and agrochemicals. The synthesis and functionalization of indoles have attracted chemists and remain an active research area. At first, we developed the palladium-catalyzed that aryl pinacol boronates chosen as boronic sources and underwent cross-coupling with C-C bond in EtOH is reported. We synthesize the 2,3-substituted indoles through the coupling reaction of arylpinacol boronates and cyclization with N,N-dimethyl-2-(phenylethynyl)aniline under mild condition. Notably, the reaction carried out in the absence of ligands, bases and acids to provide simple synthesis of indole derivatives.

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Tien, Shih-Wei, and 田世維. "Preparation and biological assessment of 4-boron pinacol methyl [18F] fluorofenbufen for potential application in positron emission tomography and boron neutron capture therapy." Thesis, 2015. http://ndltd.ncl.edu.tw/handle/pvh9v9.

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碩士
國立清華大學
生醫工程與環境科學系
103
By using 4-bromobiphenyl as starting material, via three steps synthesis, we obtain methyl 4-oxo-4-(4'-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)-[1,1'-biphenyl]-4-yl)butanoate (6) with chemical yield 81.6%. After radio-labeling by [18F] F2, 4-boron pinacol methyl [18F] fluorofenbufen (FFBpin) was prepared with a radiochemical yield 3.3% and the specific activity was 12.3 MBq/ μmole. To figure out the structure of FFBpin, we compared FFBpin’s NMR and mass spectrometry with precursor’s. The 1H-NMR signal of precursor at δ 7.80 and δ 7.85 disappeared, and three new signals raised at δ 7.51, 7.56 and 7.65. The 19F-NMR showed that there were two signals at δ -119.07 and δ -119.6. Calculated by the Hesse Meier Zeeh equation, we deduced the fluorine atom locating on the ortho and meta site of boron atom. The result showed that [18F] FFBpin preferentially interacts with COX-1 and the IC50 is 3.16 μM comparing with that of COX-2 in 11.22 μM. [18F] fluorocelecoxib binds COX-2 with IC50 0.13 nM and that of COX-1 with IC50 12.59 nM. Besides, increasing accumulation of [18F] FFBpin from 1% to 1.5% in HuCCT1 was observed during 2 hrs-study, in contradictory to a plain accumulation by fibroblast cell.

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Hsu, Teng-Yi, and 許籐譯. "（I）The influences of reaction conditions on preparations of 1-acetyl-7-(3-oxo- butyl)-2,3,7-triaza-bicyclo[3.3.0]oct-2-ene （II）Preparation of pinacol using TiCl4－Zn." Thesis, 2006. http://ndltd.ncl.edu.tw/handle/52846922544335255057.

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碩士
中原大學
化學研究所
94
First part This thesis addresses on the influences of reaction conditions on preparations of 1-acetyl-7-(3-oxo- butyl)-2,3,7-triaza-bicyclo[3.3.0]oct-2-ene .In previous protocol ,directly adding methyl vinyl ketone for one pot reaction ,a residual side product was produced。After a series of study ,we found that the side product that was a dihydropyran from the [4＋2] cycloaddition of two molecules of methyl vinyl ketone .Thus by mixing allyl bromide and sodium azide and allowing the reaction to proceeds for 12 hours，then adding methyl vinyl ketone dropwise ,a remarkable improvement on the problem of the residual product was obtained .Then we utilize the improved conditions , replacing allyl bromide by 3-chloro-2-methyl propene ,to produce 1-methoxyl-5-methyl-7-(2-methoxylethylene)-2,3,7-triaza-bicyclo[3.3.0]oct-3-enes in one pot reaction .But these conditions were not suit methyl acrylate and acrylonitrile .Besides，This thesis also addresses on the reaction of methyl acrylate in a mixed solvents of methanol and acetone in 1：4 ratio .Although we can synthesis 1-acetyl-7-(3-oxo-butyl)-2,3,7-triaza-bicyclo[3.3.0]oct-2-ene in one pot reaction ,but we do not get a better result than previous protocol . Second part This thesis addresses on a series of study on the preparation of pinacol using TiCl4－Zn .In the past , principally utilize TiCl4－Zn to study about Wittig Reaction .Herein ,the mixture of TiCl4 and zinc powder in THF were stirred for 1 hour and then ketone was added to obtain pinacol .

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許宏泰. "Studies on catalytic properties of metal-substituted molecular sieves in synthesis of vitamin K3 and FeAPO-5 catalytic mechanism in pinacol rearrangement reaction by in-situ X-ray absorption spectroscopy." Thesis, 2002. http://ndltd.ncl.edu.tw/handle/37711756060321587987.

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32

Görmen, Meral. "Synthèse de composés organométalliques de la série du ferrocénophane et évaluation de leurs activités antiprolifératives sur les cellules du cancer du sein et de la prostate." Phd thesis, 2010. http://pastel.archives-ouvertes.fr/pastel-00600598.

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L'utilisation de composés organométalliques pour le traitement des cancers est l'un des domaines de la chimie bioorganométallique qui connait une expansion rapide. Parmi les composés développés en endocrinologie, les composés les plus intéressants et très étudiés sont les dérivés ferrocéniques du tamoxifène. Ils sont développés par le groupe du Professeur Gérard Jaouen. Parmi ces composés, le ferrocifène et le ferrociphénol sont très actifs contre les cellules cancéreuses hormono-dépendantes (MCF-7) et hormono-indépendantes (MDA-MB-231) du cancer du sein. Le ferrocénophanyl diphénol, un dérivé phénolique de la série ferrocénophane et analogue du ferrociphénol, s'est montré plus actif que celui-ci. Dans le but de verifier cette caractéristique et aussi de trouver de meilleures molécules, de nouveaux composés de la série ferrocénophane ont été synthétisés et étudiés. Les nouveaux composés sont des 1-(diarylméthylidène)-[3]ferrocénophanes, portant un ou deux substituants (R1, R2 = H, OH, OAc, NH2, NHAc, Br, CN, NHCO(CH2)2NMe2, O(CH2)3NMe2 ou O(CH2)2COOEt) en para du cycle aromatique. L'activité antitumorale de ces composés prouve que la série des ferrocenophanes est plus efficace que la série des ferrocènes contre les cellules cancéreuses du sein. Les études ont été également menées sur les pinacols et les produits résultant de l'arrangement pinacolique. Ces deux produits ont été péparés à partir de la réaction de couplage de McMurry. On trouve que les pinacols sont très actifs contre les cellules cancéreuses MDA-MB-231. Cependant les produits de transposition sont peu réactifs. Ce travail montre que la série des ferrocénophanes est plus efficace que la série des ferrocènes contre les céllules cancéreuses du sein.

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Dissertations / Theses on the topic 'Pinacois'

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