Dissertations / Theses on the topic 'Tartaric acid'
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1
Xie, Wei. "Thermodynamic and structural studies of aqueous chelating agents and their metal complexes at various temperatures and pressures : diethylenetriaminepentaacetic acid (DTPA) and tartaric acid /." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1999. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape7/PQDD_0030/MQ47491.pdf.
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Mhatre, Bharat Suresh. "Super-enantiospecific Autocatalytic Decomposition of Tartaric Acid and Aspartic Acid on Cu Surfaces." Research Showcase @ CMU, 2013. http://repository.cmu.edu/dissertations/232.
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Autocatalytic reaction mechanisms are observed in a range of important chemical processes including catalysis, radical-mediated explosions, and biosynthesis. Because of their complexity, the microscopic details of autocatalytic reaction mechanisms have been difficult to study on surfaces and heterogeneous catalysts. Autocatalytic decomposition reactions of tartaric acid (TA) enantiomers adsorbed on Cu(110) offer molecular-level insight into these processes, which until now, were largely a matter of speculation. The decomposition of TA/Cu(110) is initiated by a slow, irreversible process that forms vacancies in the adsorbed TA layer, followed by a vacancy-mediated, explosive decomposition process that yields CO2 and small hydrocarbon products. Initiation of the explosive decomposition of TA/Cu(110) was studied by measurement of the reaction kinetics, time-resolved low energy electron diffraction (LEED), and time-resolved scanning tunneling microscopy (STM). Initiation results in a decrease in the local coverage of TA and a concomitant increase in the areal vacancy concentration. Once the vacancy concentration reaches a critical value, the explosive, autocatalytic decomposition step dominates the subsequent TA decomposition rate.
Aspartic acid is an excellent probe molecule for investigating the surface chemistry of autocatalytic reactions . Because a wide range of isotopically labeled varieties of aspartic acid are commercially available, we have been able to conduct a detailed investigation of its autocatalytic reaction mechanism. Experimental data obtained for variable initial coverage, variable heating rate and isothermal TPRS experiments, while monitoring CO2 desorption is in excellent agreement with a rate law which explicitly accounts for an initiation step and an explosion step which is second order in vacancy concentration
Autocatalytic surface explosion mechanisms can be exploited to attain extremely high enantiospecificities in the case of TA decomposition on naturally chiral Cu(hkl)R&S surfaces. Interaction energies of chiral molecules with naturally chiral surfaces are small and typically lead to modest enantioselectivities. However, the highly non-linear kinetics of autocatalytic reaction mechanism amplifies these small differences to result in high enantiospecificities. The observed phenomenon has the characteristics of autocatalytic processes that have been postulated to lead to biomolecular homochirality in life on Earth; processes with relatively small differences in reaction energetics that, nonetheless, lead to extremely high enantioselectivity.
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Basaran, Tolga Yener. "Ion Exchangers In The Recovery Of Tartaric Acid From Aqueous Solutions." Master's thesis, METU, 2006. http://etd.lib.metu.edu.tr/upload/12607367/index.pdf.
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Tartaric acid is a dicarboxylic acid naturally present in grapes, and has many application areas with its salts. It can be produced synthetically, manufactured as a by-product in wine industry, or can be recovered by electrodialysis and solvent
extraction methods. Since, ion exchange is one of the oldest processing techniques for the recovery and purification of valuable materials, it can be applied to obtain this valuable organic acid. In this study it is aimed to investigate the
effects of resin basicity, initial concentration, and initial pH of the solution on ion exchange equilibrium.
The model tartaric acid solutions were prepared for the equilibrium analysis with two different anion exchange resins in a batch type system. A shaker bath at 28 oC with 300-rpm agitation rate was used. The weakly basic resin Lewatit MP62, and strongly basic resin Lewatit M511, which are in polystyrene structure, was obtained from the producer Bayer AG. In the analysis, Shimadzu PDA Detector at 210 nm
with Waters Atlantis dC18 column was used. 20 mM NaH2PO4 at pH = 2.7 was introduced to the HPLC as the mobile phase at 0.5 ml/min flow rate.
In the investigation of the resin basicity, MP62 presented better performance than M511. The equilibrium experiments were performed at three different initial acid concentrations (0.01, 0.02, and 0.10 M) for both resin, and in the pH ranges pH <pKa1, pKa1 <
pH <
pKa2, and pKa2 <
pH for weakly basic resin, and in the pH ranges pH <
pKa1, pKa1 <
pH <
pKa2 for strongly basic resin at each concentration. Results show that the pH of the solution is a more important parameter than the initial concentration that affects the ion exchange equilibrium. Also, Langmuir and Freundlich isotherms were plotted, and it was shown that they were in good agreement with the experimental data especially for the systems that are at low total ion concentrations.
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Bakka, Thomas Aleksander. "Synthesis and Mechanistic Studies of Optically Active Tartaric Acid Based Surfactants." Thesis, Norges Teknisk-Naturvitenskaplige Universitet, 2013. http://urn.kb.se/resolve?urn=urn:nbn:no:ntnu:diva-20995.
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Gaining knowledge of the isomerization mechanisms are of pivotal importancefor stereochemically pure synthesis. Optically pure tartaric acid basedsurfactants are seen as important precursors for optically active superstructures.From these superstructures, liposomes are known canditates for drugdelivery nanovessels in the human body.A number of optically pure reference compounds were synthesized and severalanalysis methods were outlined.A mechanistic route for formation of cyclic tartrimides in nonpolar solvents have beenproposed on the background of various mechanistic assessment techniques.
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Lopez, Martinez Marco Antonio. "Studies of tartaric acid modified nickel supported catalysts for enantioselective hydrogenation reactions." Thesis, University of Birmingham, 2011. http://etheses.bham.ac.uk//id/eprint/1491/.
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This thesis investigates the catalytic properties of tartaric acid‐nickel supported catalysts, obtained from hydrotalcite‐like compound precursors, in the enantioselective hydrogenation of methyl acetoacetate to methyl 3‐hydroxybutyrate. Variables of reaction during modification such as pH and tartaric acid concentration, as well as Ni particle size above a minimum threshold of ca. 20 nm, proved not to have a major effect on enantioselectivity. However, the nature of the cations constituting the catalyst support was found to influence the enantioselectivity observed. Specifically, when iron or chromium were constituents of the supporting oxide matrix, enantioselectivities were found to be much higher. For systems containing nickel, magnesium (or zinc) and aluminium as the cations present in the parent hydrotalcite phase, when a series of materials of the same composition obtained from different synthetic methods, the urea hydrolysis method leads to catalysts with enantiodifferentiation ability, whereas materials prepared by the coprecipitation method does not. Also, this thesis researches the use of different types of ordered mesoporous silicas as supports of tartaric‐acid nickel in the aforementioned reaction. Even though the techniques of metal deposition explored did not allow incorporation of Ni in the internal surface of the materials, it was found that the morphology of the support plays an important role in enantioselectivity. In addition, for a given material, the incorporation of Ni via solid state reaction resulted in a catalyst with improved catalytic properties compared to one prepared by wet impregnation techniques.
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Hayes, Monty. "Chiral and racemic calix[6]arenes and their self-assembly /." View online, 2008. http://ecommons.txstate.edu/bchemtad/5.
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Wade, Charles. "Studies towards the total synthesis of isoavenaciolide and the development of the amino tartrate aldol reaction." Thesis, University of Sheffield, 2001. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.341816.
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Japu, Cristina. "Cyclic derivatives of D-glucose and tartaric acid as building blocks for renewable polyesters." Doctoral thesis, Universitat Politècnica de Catalunya, 2014. http://hdl.handle.net/10803/284660.
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Three series of aromatic copolyesters derived from poly(ethylene terephthalate) (PET), poly(butylene terephthalate) (PBT) and poly(hexamethylene terephthalate) (PHT) have been synthesized by melt polycondensation in which the terephthalate and oxyalkylene units have been partially or totally replaced by monocyclic and bicyclic diacids and diols obtained by derivatization of renewable monomers such as tartaric acid and D-glucose respectively. Another series of aliphatic copolyesters derived from poly(butylene sebacate) has been prepared by both melt polycondensation and enzymatic polymerization in solution where both the sebacate and butylene units have been partially or totally replaced by the bicyclic diacid or diol derived from D-glucose. All series of polyesters and copolyesters were characterized by FTIR and NMR in solution. The chemical composition of the copolyesters was determined by 1H NMR. On the other hand the microstructure, determined by 13C NMR was observed to be at random for all series. The molecular weights determined by intrinsic viscosimetry and gel permeation chromatography (GPC) were high but decreasing when the content of the sugar monomer increased. The thermal properties were evaluated by differential scanning calorimetry (DSC) and thermogravimetric analysis. It was observed that the thermal stability was not affected when the oxyalkylene unit was the replaced unit, but decreased slightly when the terephthalate unit was replaced one. The new copolyesters showed higher glass transition temperatures than the parent poly(alkylen terephthalate)s, being superiors for the copolyesters obtained from the bicyclic derivative of D-glucose than for the monocyclic derivative of tartaric acid. All copolyesters were less crystalline than the parent homopolyesters, with both melting and enthalpies decreasing with the increased content of the sugar units. The crystalline structure determined by X-ray diffraction was similar to the PET, PBT and PHT polyesters. Finally it was studied the hydrolytic and enzymatic degradability by weight loss, molecular weight determinations and scanning electron microscopy (SEM). All new copolyesters showed enhanced degradability in water and biodegradability.En esta Tesis se han sintetizado mediante reacción de policondensación en masa tres series de copoliesteres aromáticos derivados del poli(etilen tereftalato) (PET), poli(butilen tereftalato) (PBT) y poli(hexametilen tereftalato) (PHT) en los que se han sustituido parcial o totalmente las unidades tereftalicas o las unidades oxialquilénicas por diácidos y dioles cíclicos y bicíclicos obtenidos por derivatización de monómeros de origen natural como son el ácido tartárico y la D-glucosa. También se han sintetizado mediante policondensación en masa y en disolución por vía enzimática una serie de copoliesteres alifáticos derivados del poli(butilen sebacato) en los que las unidades oxibutilénicas y sebácicas se han reemplazado por dioles y diácidos bicíclicos derivados de la D-glucosa. Todas las series se han caracterizado espectroscópicamente mediante FTIR y RMN en disolución. Mediante RMN de 1H se ha determinado la composición de los copolímeros. Por otro lado mediante RMN de 13C se ha estudiado la microestructura de los mismos. Dicho estudio reveló que todos los copolímeros eran al azar. Los pesos moleculares determinados mediante cromatografía de permeabilidad en gel y viscosimetría capilar resultaron ser aceptables, aunque en todos los casos disminuían a medida que aumentaba el contenido del monómero de origen renovable. Las propiedades térmicas se han evaluado mediante calorimetría diferencial de barrido (DSC) y análisis termogravimétrico. Se ha observado que la estabilidad térmica no se ve apenas afectada cuando la sustitución se realiza sobre la unidad oxialquilénica y que por otro lado desciende cuando es la unidad tereftálica la sustituida. Los nuevos copolímeros presentaron temperaturas de transición vítrea superiores, observándose que este aumento era superior en los copolímeros que incorporaban el diol o el diácido bicíclico derivado de la D-glucosa que en los que incorporaban el diol o el diácido monociclico derivado del ácido tartárico. Los copolimeros eran por lo general menos cristalinos, menos cristalizables y con temperaturas de fusión inferiores. La estructura cristalina de los mismos determinada mediante difracción de rayos-X era semejante a la de los homopolimeros PET, PBT y PHT. Se ha estudiado la degradabilidad hidrolitica y la biodegradabilidad de todos ellos mediante medidas de pérdida de peso, pesos moleculares, microscopía electrónica de barrido (SEM), observándose un aumento de ambas propiedades para los nuevos copolímeros.
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Morello, Alessandro. "Influence of ph and temperature on metatartaric acid efficiency in white wine tartaric stabilization." Master's thesis, ISA/UL, 2012. http://hdl.handle.net/10400.5/8625.
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Mestrado Vinifera EuroMaster - Instituto Superior de AgronomiaThe sensitivity of metatartaric acid (MA) to high temperatures is the main limit for its actual use in enology. For this reason MA is generally used only for ready-to-drink wines that are stored for few months in bottle. The objective of this work was to obtain more information about the use of MA in order to prevent tartaric salts precipitation in wine by monitoring its effectiveness along the time. Tartaric stability was followed in a white wine during a ten-week experiment. 10 g/Hl of MA was added to wines with different five pH values, namely 3.0, 3.2, 3.5, 3.7 and 3.9 at room temperature (20°C), and to wines at original pH of 3.2 under three different temperatures commonly found in real storage conditions, precisely 12°C, 20°C and 35°C. To monitor tartaric stability we used a test based on the electrical conductivity developed by Boulton (1983). At the end of the experiment we found both a pH and a temperature effect. It was found a polynomial relation (R2 = 0,85) between tartaric stability and pH. The highest the pH, the highest the instability and the shortest the protection against tartrates precipitation. Furthermore, over 20°C we observed a rapid general decrease of MA effectiveness and that there was a linear relation (R2 = 0,99) between temperature and tartaric stability, so that we can affirm that the highest the temperature, the higher the wine instability; this is probably due to a faster MA hydrolysis. Metatartaric acid is surely able to prevent tartrates precipitation, but since in our experimental conditions it could not protect the wine for longer than one month, we would suggest extreme prudence about its use especially during long storage periods
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Guadagnin, Hellen Costerano. "Corrosion resistance study of AA2524 anodized in sulphuric-tartaric acid and sealed with hybrid coatings." Universidade de São Paulo, 2017. http://www.teses.usp.br/teses/disponiveis/3/3137/tde-20072017-152947/.
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Aluminium alloys are widely used in the aerospace industry due to their lightweight and high specific strength. However, these alloys are particularly sensitive to localized corrosion in chloride environments and need to be protected by a robust system. One of the protection methodologies consists in anodizing. The produced layer increases the corrosion resistance and also serves as anchoring site for organic coatings application. Chromium-based anodizing has been usually employed, nevertheless, as chromate compounds are toxic for health and the environment, chromium-based surface treatments will be prohibited in the aerospace industry in a near future. Tartaric-sulphuric acid (TSA) anodizing is a promising environment compliant alternative, which is already being used at industrial level with appropriate corrosion protection and paint adhesion properties. This study aims at proposing a hybrid sol-gel treatment after TSA anodizing of AA2524 specimens in order to improve the corrosion resistance of the anodized layer while maintaining its compatibility with organic coatings. For this, anodic aluminium oxides (AAO) were produced at different anodizing voltages and protected by dip-coating with a hybrid sol-gel layer obtained from a tetraethoxysilane (TEOS) and 3-glycidoxypropyltrimethoxysilane (GPTMS) hydrolysis solution with high water content. Corrosion resistance evaluation was carried out by means of electrochemical impedance spectroscopy (EIS) in NaCl 0.1 mol L-1 and salt-spray chamber exposure (ASTM B117-11 standard). The morphology of the anodic porous layer was investigated by means of FE-SEM, whereas glow discharge optical emission spectroscopy (GDOES) was employed to evaluate the distribution of the sol-gel layer within the porous AAO. FE-SEM characterization confirmed that the layer properties (pore distribution, porosity and thickness) were strongly dependent on the anodizing conditions, whereas GDOES depth profile showed penetration of the hybrid coating within the pores of the anodized layer. The two characterization techniques showed inefficient surface sol-gel coverage for the samples anodized at higher voltage, likely due to insufficient sol-gel deposition. The results of the EIS characterization tests up to 1008 h (42 days) showed that, irrespectively to the anodizing voltage, the hybrid sol-gel protected AAO was stable with only slight evolution of the diagrams with immersion time. Moreover, the hybrid coating protected samples presented higher low frequency impedance modulus than hydrothermally sealed (HTSed) reference TSA anodized samples, which was confirmed by electrical equivalent circuit (EEC) fitting of the EIS data. EEC fitting also revealed that the resistance of the pores to electrolyte penetration was increased by the application of the sol-gel coating when compared to the resistance of the HTSed reference samples and indicated better anticorrosion performance for the sample anodized at 16 V. These results were confirmed by the salt-spray tests. Investigation on the ageing of the hybrid sol-gel hydrolysis solution showed that its viscosity hardly changed up to two weeks of test and that hybrid coatings applied from these solutions were stable and afforded good corrosion protection to the TSA anodized substrate, an improvement of the anticorrosion properties of the hybrid coating was verified for an ageing time of 168 h. Preliminary tests performed with a solvent-free organic coating (epoxy) indicated good compatibility with the hybrid TEOS-GPTMS coating characterized by very high impedance and good stability upon exposure to the salt-spray chamber.Ligas de alumínio são muito utilizadas na indústria aeronáutica por serem materiais leves e altamente resistentes. Porém, essas ligas são particularmente sensíveis à corrosão localizada em meios que contêm cloretos, e precisam de sistemas robustos de proteção. Uma das metodologias de proteção consiste em anodização. A camada produzida aumenta a resistência à corrosão e também serve como sítio de ancoragem para aplicação de revestimentos orgânicos. A anodização crômica tem sido usualmente empregada na indústria aeronáutica. No entanto, como compostos contendo íons cromato são tóxicos para a saúde e para o meio-ambiente, tratamentos de superfície à base de cromo serão proibidos na indústria espacial em um futuro próximo. Anodização em banho de ácido sulfúrico-tartárico (TSA) é uma alternativa promissora e ambientalmente compatível, a qual já está sendo usada industrialmente com apropriada proteção à corrosão e adesão para pintura. Este estudo tem como objetivo propor um tratamento utilizando um revestimento híbrido sol-gel para melhorar a resistência à corrosão da liga AA2524 anodizada em TSA e que mantenha sua compatibilidade com revestimentos orgânicos. Para isso, camadas anodizadas de alumínio (CAA) foram produzidas em diferentes voltagens e protegidas por camada de híbrido sol-gel obtida pela hidrólise de tetraetilortosilano (TEOS) e glicidóxipropiltrimetóxisilano (GPTMS) em solução com alto teor de água e aplicada pela técnica de dip-coating. A avaliação da resistência à corrosão foi realizada através de espectroscopia de impedância eletroquímica (EIS) em NaCl 0,1 mol.L-1 e por exposição à câmara de névoa salina (norma ASTM B117-11). A morfologia da camada porosa foi investigada por MEV e a espectroscopia de emissão óptica por descarga luminescente (GDOES) foi empregada para avaliar a distribuição do híbrido sol-gel no interior dos poros da camada porosa. As caracterizações por MEV confirmaram que as propriedades da camada (distribuição dos poros, porosidade e espessura) são fortemente dependentes das condições de anodização, e a composição em profundidade obtida por GDOES mostrou que o revestimento híbrido penetrou nos poros da camada anodizada. As duas técnicas de caracterização mostraram uma cobertura ineficiente da camada sol-gel para as amostras anodizadas nas voltagens mais elevadas, provavelmente devido à deposição insuficiente do híbrido. Os testes de EIS com duração de até 1008 h (42 dias) mostraram que, independentemente da voltagem de anodização empregada, a camada anódica coberta com sol-gel ficou estável ocorrendo apenas pequenas evoluções dos diagramas com o tempo de imersão. Além do mais, as amostras protegidas com o revestimento híbrido apresentaram maiores valores de módulo de impedância em baixa frequência do que as amostras anodizadas em TSA e hidrotermicamente seladas (HTsed) usadas como referências. Essa tendência foi confirmada pelo ajuste com circuitos elétricos equivalentes (EEC) dos resultados de EIS que também mostrou que a aplicação do sol-gel híbrido torna mais difícil a penetração do eletrólito agressivo nos poros da camada anodizada quando comparada com as amostras HTSed, e indicou melhor desempenho anticorrosivo para a amostra anodizada em 16 V. Esses resultados foram confirmados pelos testes de névoa salina. A investigação do envelhecimento da solução de sol-gel mostrou pouca mudança na viscosidade da solução de hidrólise em duas semanas de testes e que os revestimentos híbridos aplicados a partir dessas soluções foram estáveis e promoveram boa proteção à corrosão para as amostras anodizadas em TSA, com melhora das propriedades anticorrosivas após 168 h de envelhecimento. Testes preliminares realizados com revestimento orgânico livre de solvente (epóxi) indicaram boa compatibilidade deste com o revestimento híbrido TEOS-GPTMS. O revestimento epóxi propiciou valores de módulo de impedância elevados e estáveis e também boa estabilidade após exposição à câmara de névoa salina quando aplicado sobre o revestimento híbrido aplicado sobre a liga 2524.
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Lorenzo, Maria Ortega. "Complexities and dynamics of the enantioselective site in heterogeneous catalysis : tartaric acid and methylacetoacetate on Cu(110)." Thesis, University of Liverpool, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.366724.
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Coetzee, Zelmari. "Site and vintage response of malic and tartaric acid in Vitis vinifera L. cv’s Cabernet Sauvignon and Sauvignon blanc." Stellenbosch : Stellenbosch University, 2013. http://hdl.handle.net/10019.1/85736.
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Thesis (MScAgric)--Stellenbosch University, 2013.ENGLISH ABSTRACT: Acids are one of the major components that originate largely from the berry, that are found in wine, and that influence the sensory perception. The presence of organic acids in adequate concentrations in the grape berry, of which tartaric- and malic acid are the main organic acids present, is important as this determines the potential of a must to produce a good and stable wine. The effect of temperature on the organic acid content of the must is widely discussed with higher temperatures in general being associated with lower quantities of organic acids present in the juice, and lower temperatures during ripening associated with higher quantities, specifically in the case of malic acid. Due to the topographical diversity of the Stellenbosch Wine of Origin district and the closeness of the ocean and the occurrence of sea breezes, the mesoclimate differs greatly over short distances. Sixteen sites, consisting of eight Sauvignon Blanc and Cabernet Sauvignon sites respectively, were selected from a broader terroir study site network. Three vintages with complete climatic datasets were selected for vintage comparisons. Climate in the study area was monitored on differing scales, and data from a weather station network, as well as from mesoclimatic dataloggers within the sites were available. The available data was firstly compared to determine the variability of the data, not only between the two climatic scales, but also between the sites. Different climate classification indices and parameters available in literature were thereafter compared and evaluated for the best representation in this area. The Huglin index was found to be a better representation regarding the thermal climatic indices. Due to the great differences between temperatures noted for the mesoclimatic loggers and the nearest automatic weather station, the use of mesoclimatic logger data was preferred, and is advised in future studies where this scale of data is available. Malic and tartaric acid has a definite synthesis period up until véraison, after which the content of tartaric acid remains constant in the berry and the content of malic acid decreases until harvest due to mainly respiration. The temperature data was therefore separated in a synthesis period from flowering to véraison, and a ripening period from véraison to harvest. In this study, clear differences were firstly seen in the climate as expected, not only between sites per vintage, but in addition between vintages and between vintages per site. The phenological differences between the sites could be largely attributed to the differences in temperature as phenology and temperature was found to be highly correlated in this study. Differences in the ripening parameters were noticed in addition to the contents of the organic acids between sites, although no definite contribution of temperature was shown to affect the contents of these compounds at either véraison or harvest. These differences may be attributed to other factors such as the soil water content and the canopy architecture. In addition, these factors all contribute in differing percentages to the differences found in the contents per site. It was found though that temperature can be used as an indicator of the organic acid content in the grape berry, considering that the temperature data is available on a mesoclimatic scale, separated in a synthesis and period of degradation, and the number of hours within the temperature thresholds are determined. Differences seen in the organic acid contents can however not only be attributed to the differences in topography and the temperature as discussed in this study.
AFRIKAANSE OPSOMMING: Sure is belangrike druifkomponente wat grootliks hul oorsprong in die korrel het, in die wyn voorkom, en die sensoriese persepsie van die wyn beïnvloed. Die voorkoms van organiese sure in genoegsame konsentrasies in die korrel, waarvan wynsteensuur en appelsuur die hoof organiese sure is, is belangrik aangesien dit die potensiaal van die sap om ʼn goeie en stabiele wyn te produseer, bepaal. Hoe temperatuur die inhoud van organiese sure in die druiwesap affekteer is gereeld onder bespreking, met hoër temperature in die algemeen geassosieer met ʼn laer inhoud van organiese sure, terwyl laer temperature geassosieer word met ʼn hoër inhoud van organiese sure in die sap, veral in die geval van appelsuur. As gevolg van die topografiese diversiteit van die Stellenbosch Wyn van Oorsprong distrik, asook die nabyheid van die oseaan met die gepaardgaande voorkoms van die seebries, verander die mesoklimaat aansienlik oor klein afstande in hierdie area. Vir die studie was sestien wingerde, wat bestaan het uit agt Sauvignon Blanc en agt Cabernet Sauvignon wingerde, geselekteer vanuit ʼn groter terroir studie. Verder was drie seisoene, met volledige klimaatsdatastelle, geselekteer vir die vergelyking van data tussen die seisoene. Klimaat was op verskillende skale binne die studie area gemonitor en data van ʼn weerstasie netwerk, sowel as van mesoklimaat dataversamelaars binne die wingerde, was beskikbaar. Die beskikbare datastelle was vergelyk, asook geëvalueer, om die mees verteenwoordigende datastel vir die area te bepaal. Met die oorweging van die termiese indekse was daar gevind dat die Huglin indeks beter verteenwoordigend van die area was. Verder, as gevolg van die groot verskille wat gevind is tussen die temperature gemeet met die mesoklimaat dataversamelaars en die naaste outomatiese weerstasie, was daar besluit dat die gebruik van die mesoklimaat data verkies is en is dit ook aan te beveel vir die gebruik in toekomstige navorsing indien die tipe data beskikbaar is. Wynsteen- en appelsuur het beide ʼn definitiewe sintese periode tot en met véraison, waarna die hoeveelheid wynsteensuur in die korrel relatief konstant bly en die hoeveelheid appelsuur afneem hoofsaaklik as gevolg van respirasie. Die temperatuur data was dus verdeel in ‘n periode van sintese vanaf blom tot en met véraison, en ʼn rypwordingsperiode vanaf véraison tot en met oes. In hierdie studie was daar eerstens groot verskille waargeneem in die klimaat soos wat daar verwag is. Hierdie verskille was nie net waargeneem as tussen die seisoene nie, maar ook tussen die wingerde binne ʼn seisoen. Die fenologiese veskille tussen die wingerde wat ook waargeneem is, kon hoofsaaklik aan die verskille in die temperatuur toegeskryf word en ʼn goeie korrelasie tussen temperatuur en fenologie is opgemerk. Merkwaardige verskille in die rypwordingsparameters, asook in die inhoud van die organiese sure, was waargeneem, alhoewel die bydrae van temperatuur op die inhoud van hierdie komponente by véraison of oes nie as definitief getoon is nie. Dit kan toegeskryf word aan die bydrae van ander faktore, soos byvoorbeeld die grondwaterinhoud en die lowerargitektuur, op die inhoud van hierdie komponente. Die addisionele faktore dra egter in verskillende persentasies by tot die verskille waargeneem tussen die wingerde.
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Gouteyron, Antoine. "Nouveaux monomères biosourcés à haute rigidité à destination des revêtements polyesters." Thesis, Lyon 1, 2015. http://www.theses.fr/2015LYO10266.
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Les résines polyesters sont des composants présents dans une majorité des revêtements et matériaux utilisés aujourd'hui. Ils sont obtenus par polycondensation de polyols, polyacides et monoacides. Les réglementations évoluant (REACH) et le public étant de plus en plus sensible à l'origine et l'impact des produits qu'il consomme, la substitution des produits pétrosourcés vers des matières premières renouvelables semble évidente. De nouveaux polyesters, composés majoritairement de monomères biosourcés, ont donc été synthétisés. L'acide L-(+)-tartrique a été principalement étudié, ce monomère quadri-fonctionnel étant peu utilisé dans la chimie des matériaux bien que disponible en grandes quantités et peu coûteux. Afin de caractériser les polyesters, différents tests utilisés dans l'industrie ont été mis en place, les caractéristiques physico-chimiques pouvant varier d'une application à l'autre. Différents mécanismes de réticulation ont également été explorés afin d'adapter les polyesters aux contraintes de résistance et de séchage requises. Ces mécanismes incluent la réaction entre les hydrazides et les méthyles cétones ainsi que celle des dérivés du Bore et des hydroxyles à température ambiante. La solubilité des polyesters synthétisés a également été étudiée afin d'obtenir un produit soluble en phase aqueuse capable de devenir insoluble après réticulation et séchagePolyester binders are the main components of the coatings and materials used nowadays. They are obtained by the condensation of polyols, polyacids and monoacids. Evolving regulations (REACH) and the public being increasingly sensitive to the origin and impact of the products it consumes, petro based compounds substitution to renewable raw materials seems obvious. New polyesters, mainly composed of biobased monomers were therefore synthesized. The L-(+)-tartaric acid was mainly studied, this quad-functional monomer being barely used in materials chemistry, although available in large quantities and inexpensive. To characterize polyesters, various tests used in the industry have been established, the physicochemical characteristics may vary from one application to another. Different crosslinking mechanisms have also been explored to adapt polyesters constraints of resistance and drying. These mechanisms include the reaction between the hydrazide and methyl ketones, as well as the derivatives of Boron and hydroxyl at room temperature. The solubility of the synthesized polyesters was also studied in order to obtain a water soluble material capable of becoming insoluble after crosslinking and drying
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Wu, Ruizhi. "Enzymatic and chemical synthesis of polyesters and polycarbonates derived from L-tartaric acid and synthesis of polycaprolactones initiated by cavitands." [Tampa, Fla] : University of South Florida, 2009. http://purl.fcla.edu/usf/dc/et/SFE0002972.
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Jones, Lee. "An investigation into the effect of a chiral adsorbate on surface magnetism using spin-resolved electron spectroscopy : tartaric acid on Ni{110}." Thesis, University of Liverpool, 2006. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.433770.
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Reinicker, Aaron D. "High Throughput Study of the Structure Sensitive Decomposition of Tartaric and Aspartic Acid on Surfaces Vicinal to Cu(111) and Cu(100)." Research Showcase @ CMU, 2015. http://repository.cmu.edu/dissertations/572.
Full textAbstract:
There are many reactions that are sensitive to the surface structure of a catalyst. In order to obtain a comprehensive understanding of structure sensitive surface chemistry we use Surface Structure Spread Single Crystals (S4Cs) that expose a continuous distribution of crystal planes across their surfaces. Those crystal planes that lack mirror symmetry contain terraces, monatomic steps, and kinks and can be described as chiral with an R or an S orientation. When coupled with spatially resolved surface analysis techniques, S4Cs can be used to study the effects of surface structure and chirality on surface chemistry across a continuous distribution of crystal planes. A set of six Cu S4Cs has been created that spans all possible crystal planes of Cu. The Cu(111) S4C was used to study the structure sensitivity of L- and D-tartaric acid (TA) decomposition and the Cu(100) S4C was used to study the structure sensitivity of L-4-13C and D-aspartic acid (AA) decomposition. Isothermal Temperature Programmed Reaction Spectroscopy (TPRS) was implemented in which the S4Cs with monolayers of TA and AA were held at a temperature below the temperature of peak decomposition observed in a standard TPR experiment (heating at 1 K/s). At various times during isothermal heating, the surface was cooled to quench the reaction. Spatially resolved X-ray Photoelectron Spectroscopy (XPS) was performed to identify those regions on the surface in which the adsorbates had decomposed and those in which they were still intact. On the Cu(111) S4C which exposes both (100) and (110) step edges, TA decomposition is most sensitive to the density of (100) steps. AA decomposition on the Cu(100) S4C was enantioselective: L-AA-4-13C decomposed on S surfaces before R surfaces while D-AA decomposed on R surfaces before S surfaces. The decomposition of CH3CH2OH, CD3CD2OD, and CF3CH2OH on Zn was studied using temperature programmed reaction spectroscopy (TPRS). The decomposition products of each reaction were determined and a reaction mechanism was proposed for CH3CH2OH decomposition based on the product ratios and peak temperature locations. The CH3CH2OH decomposition mechanism includes the formation of two intermediate species on the surface: CH3CH2- to form CH2=CH2 and CH3CH2O- to form CH3CH=O.
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Kniel, Kalmia Elisabeth. "Evaluation of chemical treatments and ozone on the viability of Cryptosporidium parvum oocysts in fruit juices." Diss., Virginia Tech, 2002. http://hdl.handle.net/10919/27243.
Full textAbstract:
Cryptosporidium parvum is a protozoan parasite historically associated with waterborne and more recently foodborne outbreaks of diarrheal illness. Contamination of certain foods, such as unpasteurized apple cider, with infective oocysts may occur as oocysts are shed in the feces of common ruminants like cattle and deer that graze in and around orchards. Cryptosporidiosis can result in a severe illness for previously healthy individuals and a life-threatening illness in immunocompromised individuals. Disease occurs after the ingestion of small infective oocysts (4 to 5 mm in size). The relatively thick membrane of the oocysts allows them to be resistant to chlorine and many other environmental pressures, making oocysts difficult to inactivate.
In this study, alternative treatments to pasteurization were evaluated for their ability to inhibit C. parvum oocyst viability in fruit juices. Oocyst viability was analyzed with a cell culture infectivity assay, using a human illeocecal cell line (HCT-8) that is most similar to human infection. The percent inhibition of infection by each treatment was determined along with the corresponding log reduction for the treatments found to be most effective. Infection by treated oocysts was compared to that of control untreated oocysts. Cell monolayers were infected with 10⁶ treated oocysts or a series of 10-fold dilutions. Parasitic life stages were visualized using an immunohistochemistry system and 100 microscope fields counted per monolayer. Organic acids and H₂O₂ were added on a wt/vol basis to apple cider, orange juice, and grape juices. Malic, citric, and tartaric acids at concentrations from 1%-5% inhibited C. parvum infectivity of HCT-8 cells by up to 88%. Concentrations ranging from 0.025%-3% H₂O₂ were evaluated where addition of 0.025% H₂O₂ to each juice resulted in a >5 log reduction of C. parvum infectivity as determined with an MPN-based cell culture infectivity assay. Treating apple cider, orange juice, and grape juice with ozone for a time period of 30 seconds up to 15 minutes at 6° and 22°C (0.9 g/L flow rate) inhibited C. parvum viability to > 90% as monitored in the cell culture assay. It is hypothesized that oocyst wall proteins that are necessary for infection are oxidized by the reactive oxygen species generated from the decomposition of the ozone and hydrogen peroxide treatments. These treatments or combinations thereof may offer potential alternatives to traditional pasteurization for fruit juices to successfully inhibit C. parvum viability.Ph. D.
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Eißmann, Diana. "Organische Linkermoleküle auf Basis natürlicher Hydroxycarbonsäuren zum Aufbau homochiraler poriger Festkörperstrukturen." Doctoral thesis, Technische Universitaet Bergakademie Freiberg Universitaetsbibliothek "Georgius Agricola", 2011. http://nbn-resolving.de/urn:nbn:de:bsz:105-qucosa-77001.
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Das Ziel dieser Arbeit bestand in der Synthese neuartiger homochiraler Molekülstrukturen, welche nach Konzepten des Crystal Engineering über ein starres Grundgerüst sowie koordinationsfähige Haftgruppen verfügen sollten. Unter Verwendung von Wein- und Milchsäure, als Vertreter der natürlich vorkommenden, enantiomerenreinen α-Hydroxycarbonsäuren, konnten die entsprechenden Derivate mit aromatischen und/oder acetylenischen Spacerelementen hergestellt und umfassend charakterisiert werden. Die synthetisierten Wein- und Milchsäureverbindungen sowie die sich von den jeweiligen Weinsäureestern ableitenden TADDOLe wurden außerdem auf ihre optische Aktivität, ihre Affinität gegenüber verschiedenen Lösungsmitteldämpfen, ihr Einschlussverhalten gegenüber achiralen und chiralen Lösungsmitteln sowie ihre Eignung als organische Linker bei der Synthese von metallorganischen Gerüststrukturen untersucht. Mittels Röntgeneinkristallstrukturanalyse konnten die Festkörperstrukturen einiger Derivate aufgeklärt und diese hinsichtlich ihrer Konformation verglichen werden.
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Butch, Christopher J. "The role of glyoxylic acid in the chemistry of the origin of life." Diss., Georgia Institute of Technology, 2014. http://hdl.handle.net/1853/54263.
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I present detailed mechanistic analysis on the chemistry of glyoxylate as it pertains to forming biologically relevant molecules on the Hadean Earth. Chemistry covered includes: 1) the dimerization of glyoxylate to form dihydroxyfumarate(DHF), a heretofore unknown reaction, important to substantiating Eschenmoser's glyoxylate scenario. 2) Formation of sugars from polymerization of glyoxylate. 3) Formation of tartrate and sugar acids from high pH reactions of DHF. 4) Formation of glycine polypeptides from glyoxylate by transamination and coupling promoted by hexamethylenetetramine. 5) Formation of glyoxylate under conditions which could be plausibly found on the early earth.
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Owens, Samuel Britt. "Transition metal complexes of bis(phosphorus) donor ligands derived from multifunctional diols synthesis, isomerization, cation binding, and catalysis /." Birmingham, Ala. : University of Alabama at Birmingham, 2008. https://www.mhsl.uab.edu/dt/2008p/owens.pdf.
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Thesis (Ph. D.)--University of Alabama at Birmingham, 2008.Additional advisors: Houston Byrd, Chris Lawson, Sadanandan Velu, Charles Watkins. Description based on contents viewed Feb. 9, 2009; title from PDF t.p. Includes bibliographical references.
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Jacquet, Antoine. "Capsules hélicoïdales d’oligoamides aromatiques : détecteurs moléculaires pour le dosage d’acides organiques du vin." Thesis, Bordeaux, 2017. http://www.theses.fr/2017BORD0921/document.
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Les foldamères – structures oligomériques artificielles adoptant une forme repliée définie – permettent la conception de récepteurs moléculaires de type capsule capables de reconnaitre sélectivement certains analytes pertinents du vin. En particulier, des récepteurs sélectifs et affins du fructose, de l’acide tartrique et de l’acide malique ont été identifiés au cours de ces dernières années. Le développement d’une méthodologie de synthèse sur support solide d’un récepteur moléculaire de l’acide gluconique sera abordé dans ce manuscrit. Cette thèse montre également comment certains de ces récepteurs peuvent être convertis en détecteurs capables d’émettre un signal en présence de l’analyte. La démarche est centrée sur l’incorporation d’un fluorophore au sein du site de reconnaissance. Une preuve de concept a ainsi été effectuée avec le dosage par fluorescence de l’acide tartrique. Enfin, le greffage de ce détecteur moléculaire à la surface de particules de silice a été réalisé et ouvre la voie au développement de dispositifs portables pour le dosage des analytes reconnus. De tels détecteurs sont requis par l’industrie du vin afin d’assurer le contrôle des processus biologiques, en particulier durant la fermentationSome relevant wine small molecular components can be selectively recognized by foldamer capsules – artificial oligomeric compounds able to fold into well-defined objects possessing an inner cavity. In recent years, selective and high affinity receptors for fructose, tartaric acid and malic acid have been reported. Here, a new methodology, using solid phase synthetic techniques, for the preparation of a gluconic acid receptor will be discussed. To transform these receptors into sensors, a fluorescent moiety has been incorporated in the binding site. A proof of concept has been achieved using a fluorescence titration of tartaric acid. Indeed, when the guest is encapsulated, a modification of the fluorescence emission is observed. Finally, these fluorescent receptors have been anchored to silica surfaces and pave the way to the development of mobile detection devices. Such sensors could be useful to the wine industry to ensure proper control of biological processes for example during fermentation
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Simões, Madalena. "Estabilização tartárica em vinhos." Master's thesis, Universidade de Évora, 2014. http://hdl.handle.net/10174/13050.
Full textAbstract:
A instabilidade do vinho em relação ao ácido tartárico e seus sais é ainda um problema
para os produtores de vinhos, sendo a estabilização tartárica dos mesmos, uma prática
corrente em enologia.
A eliminação de uma fração do ácido tartárico é geralmente conseguida pela sua
precipitação pelo frio, com intervenção de catiões presentes no vinho, nomeadamente
potássio (K) e cálcio (Ca). Existem no entanto outras alternativas, como por exemplo
resinas de troca iónica que removem os catiões K e Ca, evitando a precipitação do
ácido tartárico.
Este estudo pretende contribuir para a compreensão do fenómeno de precipitação
deste ácido nas formas de tartarato de cálcio e de hidrogenotartarato de potássio,
avaliando a estabilidade tartárica em diferentes vinhos brancos e tintos, de seis
ensaios feitos à escala industrial com recurso a um equipamento de troca iónica de
permutadores catiónicos, comparativamente a outras técnicas tradicionais de
estabilização tartárica, como sejam o tratamento pelo frio e o tratamento com a
adição de ácido metatartárico.
O estudo efetuado permitiu concluir que a utilização do equipamento de troca iónica
conduz a vinhos estáveis do ponto de vista tartárico, sendo que as principais alterações
nas características dos vinhos se verificam nos valores de pH e da acidez total, com
consequências na cor dos vinhos, especialmente no caso dos vinhos tintos; Tartrate Stabilization of Wine
Abstract:
Wine instability concerning tartaric acid and its salts is still a difficult problem for wine
producers, as tartaric stabilization is a normal practice in winemaking.
The elimination of some tartaric acid occurs normally through its precipitation at low
temperatures, with intervention of cations present in wine, mainly potassium (K) and
calcium (Ca).
Nowadays ion exchange resins can be used to remove K and Ca cations, avoiding
tartaric acid precipitation.
This study aims to gain insight of tartaric acid precipitation phenomena, either in the
form of calcium tartrate or potassium hydrogen tartrate, evaluating the tartaric
stability of white and red wines using an equipment of ion exchange and comparing it
with the traditional tartaric stabilization methods, cold stabilization and metatartaric
acid.
Tartaric acid content by HPLC and cations by flame atomic absorption spectrometry
were determined. Tartaric stability was evaluated by mini contact and saturation
temperature methods.
With the use of the ion exchange resins, stable wines were obtained. Differences in pH
and total acidity were also observed with consequences in color, especially regarding
red wines.
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Poot, Thirza. "Tuned sustainable anodic coatings for reduced ice adhesion." Thesis, Linköpings universitet, Molekylär ytfysik och nanovetenskap, 2019. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-158214.
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Aluminum alloys are widely used materials in the aircraft industry due to their high specific strength and durability. The natural corrosion resistance of aluminum can be improved through an electrochemical anodizing process. Due to recent restrictions in the use of chromic acid with toxic hexavalent chromium as electrolyte, the industry has shifted towards the use of the functional comparable tartaric sulfuric acid (TSA). TSA anodizing provides a porous alumina layer with good corrosion resistance, yet there is a desire to tune the process to fit other purposes. For instance, ice accretion to aircraft surfaces implies a safety risk and reduced energy efficiency. Due to insufficient active anti-icing systems, aircraft manufacturers are in the search for passive anti-acing materials. The ice adhesion properties of a material are thought to be affected by wettability. In turn, the wettability is affected by the morphology of the alumina influenced by the anodizing conditions. Herein, the effects of the anodizing voltage, electrolyte temperature and anodizing time on the morphology and wettability of TSA-anodized aluminum alloy 2024-T3 were studied by scanning electron microscopy (SEM) and contact angle (CA) measurements. The morphology in relation to wettability and ice adhesion strength as well as the use of posttreatments such as hydrothermal sealing and silanization was investigated. SEM images show a clear influence by the anodizing conditions on the porosity, interpore distance and pore diameter of the porous alumina. The morphology has influence on the wettability although the relationship needs further investigation. A superhydrophobic surface obtained by silanization of a surface anodized at high voltage characterized by a rod-like morphology has potential as a passive anti-icing surface. Future work may include additional polishing pretreatments, testing of additional parameters, investigating the CA hysteresis and roll-off angle as well as measuring the adhesion strength of high-impact ice. By tuning the morphology of sustainable anodic coatings, the research area is one step closer to implementing passive anti-icing materials in aircrafts.
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Duchêne, Eric. "Une exploration des possibilités génétiques pour l'adaptation de la vigne au changement climatique." Thesis, Strasbourg, 2015. http://www.theses.fr/2015STRAJ059/document.
Full textAbstract:
Les effets du changement climatique ont d’ores et déjà été observés sur la vigne : avancement des stades de développement, augmentation des teneurs en alcool des vins, baisse excessive de leur acidité. Une des voies d’adaptation possible de la viticulture est la création de nouvelles variétés. J’ai caractérisé la variabilité phénotypique de 120 descendants de croisements entre Riesling (RI) et Gewurztraminer (GW) pour (1) les stades de développement, décrits à l’aide de sommes de températures (2) la capacité à accumuler des sucres dans les raisins (3) les paramètres de l’acidité des raisins. L’utilisation de marqueurs moléculaires sur l’ADN a permis de mettre en évidence des relations entre données génétiques et phénotypiques pour tous les caractères étudiés (QTLs ou Quantitative trait loci). La principale conclusion est que la variabilité génétique pour les paramètres de l’acidité des raisins est la voie à valoriser en priorité pour l’adaptation de la vigne au changement climatiqueThe effects of climate change have already been observed on the grapevine : advance of phenological stages, increase in the alcohol content of the wines, excessive decrease of their acidity. Breeding new varieties is one of the possible means of adaptation. I have characterized the phenotypic variability of 120 genotypes, offspring from crossings between Riesling (RI) and Gewurztraminer (GW)for (1) the developmental stages, described with heat sums (2) the ability to accumulate sugars in the berries (3) the parameters for acidity. The use of DNA molecular markers allowed the detection of quantitative trait loci (QTLs) for all the traits studied. The main conclusion is that the genetic variability for the parameters determining the acidity of the berries is the most promising for the adaptation of grapevine cultivation to climate change
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SCHWARTZ, VERONIQUE. "Protection des cetones insaturees steroides en position 3 par des cetals tartriques." Nice, 1995. http://www.theses.fr/1995NICE4832.
Full textAbstract:
La preparation d'analogues structuraux de l'acetate de nomegestrol, comportant diverses modifications en position 17, a constitue un des objectifs de recherche des laboratoires theramex. Pour cela, nous avons donc ete conduits a etudier la protection de l'enchainement particulier 6-methyl-dienonique en serie 19-nor steroide, en vue d'aboutir a un intermediaire de synthese 17-cetonique. L'utilisation des cetals glycoliques classiques ne convenait pas a cause de la grande sensibilite a l'hydrolyse acide des composes prepares. Nous avons donc envisage un autre groupement protecteur: les cetals tartriques. Nous avons etudie la reaction sur l'acetate de nomegestrol, afin d'optimiser les conditions experimentales. Les cetals tartriques prepares ont ensuite ete soumis a differentes conditions d'hydrolyse acide. L'hypothese de depart est verifiee: les groupements esters et amides de l'acide tartrique permettent, en effet, la stabilisation a l'hydrolyse acide des dioxolanes allyliques. D'autre part, en appliquant la reaction sur un derive dicetonique en position 3 et 17, nous avons montre que l'encombrement des reactifs tartriques induisait une cetalisation plus regioselective que l'ethylene glycol
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Thomson, C. C. "Rootstock and canopy density effects on grape berry composition : organic acid composition, potassium content and pH." Lincoln University, 2006. http://hdl.handle.net/10182/772.
Full textAbstract:
The influence of rootstock and canopy density on grape berry composition was investigated over the summer of 2003-2004 on a commercial vineyard at Waipara, North Canterbury. This experiment was designed to investigate the influence of rootstock and canopy density on the acid composition, potassium (K) content and final pH of harvested fruit (Pinot Noir AM 10/5 Lincoln Selection). The trial block consisted of eight rootstocks laid out to an 8 x 8 latin square, each plot consisting of five vines of the same rootstock. Two canopy treatments were overlaid the block (down whole rows, assigned randomly, four rows to each treatment); one treatment allowed to grow naturally, in the other treatment the canopy was thinned removing double burst shoots and laterals. The bunch numbers were adjusted in the Unthinned canopy treatment (UCT) to match the Thinned canopy treatment (TCT). Information was gathered to assess: the canopy size and density (Pinot Quadrat Leaf Layer and Percent Gaps and canopy porosity), the plant yield (and berry size, berries per cluster, cluster weight, clusters per plant), plant K levels at flowering and veraison (from petioles and leaf blades) and berry composition at harvest (soluble solids (as brix), K, titratable acidity (TA), tartaric acid concentration, malic acid concentration and pH). The trial area was non-irrigated on clay loam soils and viticultural management was to best commercial practice. It was found that although rootstock influenced the levels of K in the plant and in the juice at harvest, the level of K in the juice did not influence pH in this experiment (range of rootstock juice K: 808 ppm to 928 ppm, l.s.d. = 75 ppm). The level of tartaric acid concentration in the juice was found to be the dominant influence on the level of pH in this experiment (rootstock pH range: 3.21 to 3.39, l.s.d. = 0.05). The juice concentration of tartaric acid was influenced by both rootstock (rootstock range 4.0 to 4.7 g/L, l.s.d = 0.4) and canopy density (UCT = 4.1, TCT = 4.7, l.s.d. = 0.4), decreased shading positively increasing the level of tartaric acid. The malic acid concentration in the juice was positively influenced by increasing canopy density (UCT = 4.7 g/L, TCT = 4.1 g/L, l.s.d = 0.4) and this played a minor role in the determination of pH in this experiment; an influence of rootstock on the level of malic acid concentration was found. The malic acid concentration strongly influenced the determination of TA (UCT = 11.0 g/L, TCT = 10.2 g/L, l.s.d = 0.5); tartaric acid concentration had a minor influence on the recorded TA. Attempts to characterise the influence of rootstock on malic acid, tartaric acid and pH were inconclusive. Rootstock was found to influence the canopy variables measured in this experiment and the recorded average plant yield. Crosses of Vitis rupestris were found to exhibit the most canopy vigour and those derived from Vitis berlandieri and Vitis riparia the least. The Canopy treatment did not show an influence over yield but the rootstock was found to influence plant yield, through the numbers of berries set in a cluster and the final harvest cluster weight. The influence of rootstock on pH may be described by the influence it exerts on canopy growth and yield but this was thought unlikely. Further research is required to describe the nature of the rootstock influence on K, malic acid, tartaric acid and pH.
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Rosa, Inês Feitinha Severino da Silva e. "O uso do poliaspartato de potássio na estabilização tartárica de vinhos." Master's thesis, Universidade de Évora, 2019. http://hdl.handle.net/10174/26199.
Full textAbstract:
A instabilidade tartárica em vinhos brancos ainda é uma preocupação em enologia, existindo várias técnicas para prevenir este problema associado à precipitação dos sais do ácido tartárico. Para além da mais usual, através da utilização do frio, podem ser utilizados aditivos que inibem o processo de formação dos cristais responsáveis pela instabilidade. Com o presente estudo, pretende-se testar um novo aditivo estabilizante, recentemente autorizado, designado por poliaspartato de potássio, na inibição da precipitação dos cristais de ácido tartárico nos vinhos, e comparar a sua eficiência com a de outros métodos de estabilização tartárica disponíveis.
Para tal, estabilizaram-se tartaricamente vinhos brancos através do frio e pela adição de manoproteína, ácido metatartárico e poliaspartato de potássio.
A estabilidade tartárica foi determinada pelo teste do mini contacto, antes e após a realização dos tratamentos de estabilização tartárica, de forma a avaliar e a comparar a eficácia dos diferentes métodos de estabilização utilizados. Por outro lado, a estabilidade tartárica ao longo do tempo, foi também avaliada nas amostras de vinho tratadas com poliaspartato de potássio; The use of potassium polyaspartate in the tartaric stabilization of wines
Abstract:
The tartaric instability in white wines is still a problem in oenology, and various techniques exist to prevent this problem associated with the precipitation of tartaric acid’s salts. Besides the most common, by using cold, additives can be used to inhibit the process of formation of the crystals responsible for the instability. With this study, the aim is to test a new stabilizing additive recently authorized, called potassium polyaspartate, on the inhibition of tartaric acid crystals precipitation in wines, and compare its efficiency with that of other available methods for tartaric stabilization.
To this end, white wines were tartarically stabilized by cold and, by adding a mannoprotein, metatartaric acid, and potassium polyaspartate.
The tartaric stability was determined by the mini contact test, before and after doing the tartaric stabilization treatments, in order to evaluate and compare the efficacy of the different used methods for stabilization. On the other hand, the tartaric stability over time was also evaluated in the wine samples treated with potassium polyaspartate.
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Lautrette, Guillaume. "Capsules hélicoïdales auto-organisées par repliement d’oligoamides aromatiques pour la reconnaissance moléculaire." Thesis, Bordeaux 1, 2013. http://www.theses.fr/2013BOR14850/document.
Full textAbstract:
La reconnaissance moléculaire constitue l’une des questions fondamentales les plus discutées dans le domaine de la chimie supramoléculaire. Cette thèse présente la conception, la synthèse et l’étude des propriétés de capsules hélicoïdales auto-organisées par repliement d’oligoamides aromatiques. Ces récepteurs sont constitués d’une chaîne oligomérique se repliant en hélice et comprenant une séquence d’unités codant pour des diamètres différents. Le repliement de l’oligomère donne naissance à une cavité pouvant accueillir des molécules invitées. La grande modularité des séquences, permettant une évolution contrôlée des structures des foldamères, donne lieu à la reconnaissance sélective et anticipée de substrats d’intérêts biologiques. Le phénomène d’encapsulation a été mis en évidence en solution par spectroscopie RMN et CD, et dans le solide par diffraction des rayons XMolecular recognition is one of the major challenges of supramolecular chemistry. Here, we present the design, synthesis and study of helical capsules properties self-organised by aromatic oligoamide folding. These receptors consist of oligomeric chains that fold into a helical conformation and comprise of a sequence of units which code for different diameters. Oligomeric folding defines a cavity which can recognize guests. The great modularity of the sequences has allowed a controlled evolution of foldamer structure resulting in the selective and predict recognition of biological substrates. The phenomenon of encapsulation was demonstrated in solution by NMR and CD spectroscopy and in the solid state by X-ray diffraction
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Cito, Antonia Maria das Graças Lopes. "Rotas sinteticas exploratorias a partir do acido L-(+)-tartarico e D-manitol." [s.n.], 1994. http://repositorio.unicamp.br/jspui/handle/REPOSIP/250182.
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Orientador : Eva Gonçalves MagalhãesTese (doutorado) - Universidade Estadual de Campinas, Instituto de Quimica
Made available in DSpace on 2018-07-19T03:12:47Z (GMT). No. of bitstreams: 1 Cito_AntoniaMariadasGracasLopes_D.pdf: 11816956 bytes, checksum: 7a6aeacceb8036c642ef2f0241838f60 (MD5) Previous issue date: 1994
Doutorado
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Alberton, Elga Heloisa. "Influência de chalconas análogas, xantonas e monossacarídeos na glicemia em modelo experimental animal." Florianópolis, SC, 2007. http://repositorio.ufsc.br/xmlui/handle/123456789/89857.
Full textAbstract:
Dissertação (mestrado) - Universidade Federal de Santa Catarina, Centro de Ciências da Saúde. Programa de Pós-Graduação em Farmácia.Made available in DSpace on 2012-10-23T03:26:54Z (GMT). No. of bitstreams: 1 240185.pdf: 599701 bytes, checksum: 17a90f318dde261b9bdb1e7c4e1b2e3a (MD5)
O objetivo deste trabalho foi estudar o efeito de chalconas análogas (derivadas do 3,4-metilenodióxi-benzaldeído, 2-naftaldeído ou xantoxilina), monossacarídeos (ácido glicônico e tartárico), extrato bruto etanólico da Polygala paniculata, fração acetato de etila (AcEt) da Polygala cyparissias (que contém xantonas), na glicemia de ratos normoglicêmicos, hiperglicêmicos e diabéticos induzidos com aloxano. Para a comparação da curva de tolerância à glicose dos compostos testados, foi realizada a curva de substâncias com efeito hipoglicemiante conhecido (insulina e tolbutamida). As glicemias foram determinadas pelo método da glicose-oxidase. As chalconas análogas foram administradas na dosagem de 5, 10 e 15 mg/kg em ratos hiperglicêmicos. As coletas de sangue foram realizadas nos tempos zero, 15, 30, 60, 120 e 180 minutos (curva de tolerância à glicose). Três séries de chalconas foram testadas, sendo que as chalconas derivadas do 3,4-metilenodióxi-benzaldeído (compostos 03, 04, 05, 07, 09 e 10) e naftaldeído (compostos 12, 13 e 14), apresentaram atividade hipoglicemiante, enquanto que as chalconas derivadas da xantoxilina não demonstraram qualquer efeito na glicemia, sugerindo assim, que substituintes na posição 3#e/ou 4# são essenciais para a atividade hipoglicêmica destes compostos. Os substituintes no anel A e B do núcleo das chalconas determina a potência e a eficiência na atividade hipoglicemiante destes novos compostos, quando comparados à insulina e à tolbutamida. O ácido glicônico foi administrado via oral nas dosagens de 25, 50, 100, 200, 400 e 800 mg/kg de peso corporal em ratos normoglicêmicos; hiperglicêmicos e diabéticos, via oral ou intraperitoneal. O ácido tartárico foi administrado nas dosagens de 100 mg/kg e 400 mg/kg via oral, em ratos normoglicêmicos e ratos hiperglicêmicos. As coletas de sangue de animais normoglicêmicos e diabéticos foram realizadas nos tempos zero, 1, 2 e 3 horas para o estudo da curva de doseresposta em função do tempo e nos tempos de zero, 15, 30, 60, 120 e 180 minutos para o estudo da curva de tolerância à glicose nos ratos hiperglicêmicos. Não houve mudança significativa nas glicemias de ratos normoglicêmicos tratados com ácido glicônico e ácido tartárico quando comparados com o tempo zero. Na curva de tolerância à glicose ocorreu aumento significativo na glicemia de animais tratados com ácido glicônico (400 mg/kg) nos tempos 15, 30, 60 e 120 minutos, e animais tratados com ácido tartárico (400 mg/kg) nos tempos 120 e 180 minutos. O ácido glicônico não alterou a glicemia de ratos diabéticos induzidos com aloxano. Estes resultados sugerem que o ácido glicônico e o tartárico não atuam como secretagogo de insulina e não possuem ação insulinomimética. O EBEtOH da P. paniculata foi administrado nas dosagens de 400, 800 e 1200 mg/kg em ratos diabéticos e hiperglicêmicos. A fração AcEt da P. cyparissias foi administrada na dosagem de 800 mg/kg em ratos diabéticos e hiperglicêmicos. A P. paniculata (EBEtOH) não alterou significativamente a glicemia de ratos diabéticos induzidos com aloxano e também a curva de tolerância à glicose nas dosagens testadas. A P. cyparissias (AcEt) não reduziu a glicemia de ratos diabéticos, mas promoveu diminuição significativa da glicemia nos tempos de 15 e 30 minutos, quando comparados ao controle hiperglicêmico. Assim, a fração rica em xantonas da P. cyparissias demonstrou potencial atividade hipoglicemiante, enquanto que a P. paniculata (EBEtOH) não demonstrou nenhuma ação anti-hiperglicêmica, anti-diabética ou insulinomimética nestes testes realizados. The objective of this investigation was to study the effect of chalcone analogues (derived from 3,4-methylenedioxy-benzaldehyde, 2-naphthaldehyde or xanthoxylin), monosaccharides (gluconic and tartaric acids), the crude ethanolic extract of Polygala paniculata, and the ethyl acetate fraction (EtAc) of Polygala cyparissias (that contains xanthones) on glycemia in normoglycemic rats, hyperglycaemic rats, and in alloxan-induced diabetic rats. The glucose tolerance curve of the compounds being tested was compared with a curve obtained using substances with a known hypoglycaemic effect (insulin and tolbutamida). Glycemia was determined by the glucose-oxidase method. The chalcone analogues were administered at doses of 5, 10 and 15 mg/kg in hyperglycaemic rats. Blood was collected at time zero and at 15, 30, 60, 120 and 180 minutes (glucose tolerance curve). Three series of chalcones were tested, those derived from 3,4-methylenedioxy-benzaldehyde (compounds 03, 04, 05, 07, 09 and 10) and naphthaldehyde (compounds 12, 13 and 14) that presented hypoglycaemic activity, and chalcones derived from xanthoxylin, which did not present any effect on glycemia, suggesting that substituents in the 3# and/or 4# positions are essential for the hypoglycaemic activity of these compounds. Substituents in the A and B ring of the nucleus of the chalcones determine the potency and efficiency in hypoglycaemic activity of these new compounds compared to insulin and tolbutamide. Gluconic acid was administered by oral route at doses of 25, 50, 100, 200, 400 and 800 mg/kg body weight in normoglycemic rats, and via oral or intraperitoneal route in hyperglycaemic and diabetic rats. Tartaric acid was administered at oses of 100 mg/kg and 400 mg/kg via oral route in normoglycemic and hyperglycaemic rats. Blood was collected from normal and diabetic animals at time zero, and then at 1, 2 and 3 hours to construct a dose-response curve as a function of time, and at time zero, then at 15, 30, 60, 120 and 180 minutes to produce a glucose tolerance curve in hyperglycaemic rats. There was no significant change in the glycemia of normoglycemic rats treated with gluconic acid and tartaric acid compared to time zero. In the glucose tolerance curve for animals treated with gluconic acid (400 mg/kg) there was a significant increase in glycemia at 15, 30, 60 and 120 minutes, while in animals treated with tartaric acid (400 mg/kg) this was present at 120 and 180 minutes. Gluconic acid did not change the glycemia in alloxan-induced diabetic rats. These results suggest that gluconic and tartaric acids do not act as insulin secretagogues and do not possess an insulinomimetic action. The EBEtOH of P. paniculata was administered at doses of 400, 800 and 1200 mg/kg in diabetic and hyperglycaemic rats. The EtAc fraction of P. cyparissias was administered at a dose of 800 mg/kg in diabetic and hyperglycaemic rats. P. paniculata (EBEtOH) did not significantly alter glycemia in alloxan-induced diabetic rats nor did it affect the glucose tolerance curve at the doses tested. P. cyparissias (EtAc) did not reduce glycemia in diabetic rats, although it did cause a significant decrease in glycemia at 15 and 30 minutes when compared to the hyperglycaemic control. In summary, the xanthones-rich fraction of P. cyparissias exhibited potential hypoglycaemic activity, while P. paniculata (EBEtOH) did not present any antihyperglycaemic, anti-diabetic or insulinomimetic action in the tests.
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DeBolt, Seth. "Tartaric acid biosynthesis in plants." 2006. http://hdl.handle.net/2440/57333.
Full textAbstract:
Title page, table of contents and abstract only. The complete thesis in print form is available from the University of Adelaide Library.To summarise, research presented in this thesis extends the understanding of grape berry metabolism by characterising dual metabolic fates for AA. Moreover, the success of combining transcriptional and metabolic profiling towards targeting a specific pathway in non-model plants was demonstrated. The key result of this research was the discovery of L-idonate dehydrogenase, which acts to oxidise L-idonate in the tartaric acid synthetic pathway. Furthermore a grape transketolase capable of carrying out a second step in the pathway was isolated and part characterised. Finally, these data present results of relevance to the applied practice of viticulture, because they reveal a differential impact of light on specific organic acids, relative to others.
http://proxy.library.adelaide.edu.au/login?url= http://library.adelaide.edu.au/cgi-bin/Pwebrecon.cgi?BBID=1241843
Thesis (Ph.D.) -- University of Adelaide, School of Agriculture and Wine, 2006
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Lin, Fu-Ming, and 林福明. "Preparation and application of chitosan-oxalic acid and chitosan-tartaric acid gel beads." Thesis, 2011. http://ndltd.ncl.edu.tw/handle/45142740967566788041.
Full textAbstract:
碩士明志科技大學
化學工程研究所
99
Chitosan-oxalate (CO) and chitosan-tartrate (CT) adsorbents, prepared by freeze-dried and oven-dried, were used for treatment of Cu(II) ion from aqueous solution. The effects of the initial pH value of the solution, contact time, temperature and the initial Cu(II) ion concentration on the adsorption of Cu(II) ion were investigated. The characterization of CO and CT adsorbents were investigated by IR, XRD and TGA. The maximum adsorption amount was observed at pH 5 for both CO and CT adsorbents. The adsorption isotherms were better fitted by the Langmuir equation. The maximum theoretical Cu(II) ion adsorption capacities of CO and CT adsorbents prepared by freeze-dried were 227.27 mg/g and 175.44 mg/g respectively. The adsorption kinetics were well described by the pseudo-second order equation, indicating that chemical adsorption is the rate-limiting step for the CO and CT adsorbents. The negative values of gibbs free energy of adsorption indicated the spontaneous adsorption of Cu(II) ion on the CO and CT adsorbents, while the positive enthalpy change indicated an endothermic adsorption process.
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Usui, Fusao. "Interaction of sodium bicarbonate with tartaric acid under compressed condition." 1985. http://catalog.hathitrust.org/api/volumes/oclc/12728166.html.
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Thesis (M.S.)--University of Wisconsin--Madison, 1985.Typescript. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references (leaves 110-112).
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Ranzenigo, Anna. "Synthesis of hydroxylated indolizidines and diamino suberic acid derivatives: use of tartaric acid and other approaches." Doctoral thesis, 2022. http://hdl.handle.net/2158/1286510.
Full textAbstract:
Tartaric acid enantiomers are very versatile and useful chiral pool compounds. Part of this research project was devoted to the study of these molecules as starting materials for the synthesis of biologically active natural products and analogs such as iminosugars and bis-a-amino acids. Bis-a-amino acids are a class of structurally interesting compounds. Among them, diaminosuberic acid is an appealing stable mimic of cystine. Object of this work was to synthetize different derivatives of diamino suberic acid using various strategies, including the tartaric acid approach, in order to get new interesting polyfunctionalized small molecules and to assess a stereoselective synthetic approach to the challenging structure of the aglycone of ascaulitoxin. Iminosugars are another class highly studied compounds. Lentiginosine is a natural iminosugar whose synthesis can be achieved by 1,3-dipolar cycloaddition of an enantiopure dialkoxypyrroline N-oxide, in turn derived from tartaric acid. The highly versatility of cyclic nitrones as precursors of azaheterocycles motivated the labeling a dialkoxypyrroline N-oxide with deuterium and its application to the synthesis of 8a-d-lentiginosine. It was also interesting to modify the parent structure of DHA, to try to control the half-life of the system and then insert an amino group useful to couple in an easy way DHA with biologically active products including amino acids. The last two projects presented, in addition to the synthetic challenge, some kinetic studies that were carried out using different techniques.
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Dhamaniya, Sunil. "Synthesis and characterization of polyesters based on tartaric acid deriv atives." Thesis, 2012. http://localhost:8080/xmlui/handle/12345678/3153.
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Chandrakumar, A. "Synthesis And Applications Of 1,4-Diketones And Y-Oxobutyramides Derived From Tartaric Acid." Thesis, 2008. https://etd.iisc.ac.in/handle/2005/839.
Full textAbstract:
The thesis entitled “Synthesis and applications of 1,4-diketones and γ-oxobutyramides derived from tartaric acid” is divided into two chapters.
Chapter 1: Synthesis of TADDOL analogues by nucleophilic addition reactions and their application to the synthesis of α-methoxy arylacetic acid derivatives
Synthesis of various TADDOL analogues by the addition of nucleophiles to 1,4-diketones derived from L-(+)-tartaric acid is presented in this chapter. It is found that the reduction of 1,4-Diketones 1a-d with K-Selectride pre-complexed with 18-crown-6 which is the optimized condition to attain better diastereoselectivity towards the C2-symmetric isomer 2a-d (Scheme 1). Addition of Grignard reagents to diketones 1a, 1eh is dependent on nature of Grignard reagents, solvent and temperature.
(Structural formula)
Scheme 1: Synthesis of TADDOL analogues
Application of the synthesized TADDOL analogues in synthesis of enantiopure α-methoxy arylacetic acid derivatives is discussed. The C2-symmetric 1,4-diols 2a-d (TADDOL analogues) are utilized in the synthesis of enantiopure α-methoxy arylacetic acid derivatives as shown in scheme 2.
Scheme 2: Synthesis of α-methoxy arylacetic acid derivatives.
(SF)
Both enantiomers of α-alkyl-α-methoxy arylacetic acids 13a-b and ent-13a are synthesized from the respective C2-symmetric diols 5a-b and 7a-b (scheme 3).
(SF)
Scheme 3: Synthesis of both enantiomers of α-alkyl-α-methoxy arylacetic acids.
Chapter 2: Facile Synthesis of α,β-dihydroxy-γ-butyrolactones and jaspine B from γ-oxobutyramides derived from tartaric acid
A short and efficient route for the synthesis of γ-alkyl/aryl-α,β-dihydroxy-γ-butyrolactones 15a-j is accomplished from γ-oxobutyramides 14a-l derived from tartaric acid. Key step includes a controlled addition of Grignard reagent and stereoselective reduction (Scheme 4).
(sF)
Scheme 4: Synthesis of α,β-dihydroxy-γ-butyrolactones and jaspine B.
Utility of the γ-oxobutyramides is further exemplified in the synthesis of jaspine B 18 a cytotoxic anhydrophytosphingosine in 48% overall yield (Scheme 5). (SF)
. Scheme 5: Synthesis of α,β-dihydroxy-γ-butyrolactones and jaspine B.
Appendix: Serendipitous observation of polymorphism in TADDOL analogue induced by the presence of chiral impurity
Polymorphism in one of the TADDOL analogues is serendipitously observed and demonstrated that the 2% impure diastereomer is responsible for the formation of one of the pol ymorphic crystals (Figure 1). (SF)
Figure 1: Diastereomeric impurity induced polymorphism.
(For structural formula pl see the pdf file)
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Chandrakumar, A. "Synthesis And Applications Of 1,4-Diketones And Y-Oxobutyramides Derived From Tartaric Acid." Thesis, 2008. http://hdl.handle.net/2005/839.
Full textAbstract:
The thesis entitled “Synthesis and applications of 1,4-diketones and γ-oxobutyramides derived from tartaric acid” is divided into two chapters.
Chapter 1: Synthesis of TADDOL analogues by nucleophilic addition reactions and their application to the synthesis of α-methoxy arylacetic acid derivatives
Synthesis of various TADDOL analogues by the addition of nucleophiles to 1,4-diketones derived from L-(+)-tartaric acid is presented in this chapter. It is found that the reduction of 1,4-Diketones 1a-d with K-Selectride pre-complexed with 18-crown-6 which is the optimized condition to attain better diastereoselectivity towards the C2-symmetric isomer 2a-d (Scheme 1). Addition of Grignard reagents to diketones 1a, 1eh is dependent on nature of Grignard reagents, solvent and temperature.
(Structural formula)
Scheme 1: Synthesis of TADDOL analogues
Application of the synthesized TADDOL analogues in synthesis of enantiopure α-methoxy arylacetic acid derivatives is discussed. The C2-symmetric 1,4-diols 2a-d (TADDOL analogues) are utilized in the synthesis of enantiopure α-methoxy arylacetic acid derivatives as shown in scheme 2.
Scheme 2: Synthesis of α-methoxy arylacetic acid derivatives.
(SF)
Both enantiomers of α-alkyl-α-methoxy arylacetic acids 13a-b and ent-13a are synthesized from the respective C2-symmetric diols 5a-b and 7a-b (scheme 3).
(SF)
Scheme 3: Synthesis of both enantiomers of α-alkyl-α-methoxy arylacetic acids.
Chapter 2: Facile Synthesis of α,β-dihydroxy-γ-butyrolactones and jaspine B from γ-oxobutyramides derived from tartaric acid
A short and efficient route for the synthesis of γ-alkyl/aryl-α,β-dihydroxy-γ-butyrolactones 15a-j is accomplished from γ-oxobutyramides 14a-l derived from tartaric acid. Key step includes a controlled addition of Grignard reagent and stereoselective reduction (Scheme 4).
(sF)
Scheme 4: Synthesis of α,β-dihydroxy-γ-butyrolactones and jaspine B.
Utility of the γ-oxobutyramides is further exemplified in the synthesis of jaspine B 18 a cytotoxic anhydrophytosphingosine in 48% overall yield (Scheme 5). (SF)
. Scheme 5: Synthesis of α,β-dihydroxy-γ-butyrolactones and jaspine B.
Appendix: Serendipitous observation of polymorphism in TADDOL analogue induced by the presence of chiral impurity
Polymorphism in one of the TADDOL analogues is serendipitously observed and demonstrated that the 2% impure diastereomer is responsible for the formation of one of the pol ymorphic crystals (Figure 1). (SF)
Figure 1: Diastereomeric impurity induced polymorphism.
(For structural formula pl see the pdf file)
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Chuang, Ya-ling, and 莊雅玲. "Electrochemical polymerization of aniline on Au(111) and Au(100) in camphor-sulfonic acid and tartaric acid." Thesis, 2011. http://ndltd.ncl.edu.tw/handle/50695091619108506870.
Full textAbstract:
碩士國立中央大學
化學研究所
99
In situ scanning tunneling microscopy (STM) and cyclic voltammetry (CV) have been used to explore the adsorption and electropolymerization of aniline on ordered Au(111) and Au(100) electrodes in 0.1 M organic acid of D-(+)- or L-(-)-camphor-sulphonic acid or D-(-)- and L-(+)-tartaric acid (TA). Molecular resolution STM imaging revealed aniline molecules were arranged differently in D-(+)- and L-(-)-camphor-sulphonic acid. The coverages and structures of aniline and coadsorbed anions could vary with the potential of gold electrodes. D-(+)- and L-(-)-camphor-sulphonic acid were able to induce 3-D helical molecular conformations of polyaniline at E > 0.95 V. On the other hand, different structures were obtained on Au(111) and Au(100) surfaces in electrolyte solutions containing aniline and D-(+)- or L-(-)-tartaric acid. Electropolymerization aniline also produced polyaniline wires with helix-like shape, which could be induced by the coadsorbed D-(-)- and L-(+)-tartaric acids. Interestingly, aniline molecules were organized differently on Au(100) electrode in D-(-)- and L-(+)-tartaric acids. Polyaniline grew linearly along the √10 direction in D-(-)- tartaric acid, followed by re-configuration into helix-like shape as oxidation of aniline continued. My studies show that chiral dopants of organic acids for polyaniline could induce specific conformational on Au(111) and Au(100) electrode surfaces. STM imaging has unveiled helical-shaped polyaniline chain in the presence of D- and L-organic acid, which could yield some fundamental insights into its potential applications in fabrication of chemical and biological sensors, chiral catalysis, pharmaceutics, and enantioselective separation.
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"Studies towards metal-complex catalyzed epoxidation." 2013. http://library.cuhk.edu.hk/record=b5884494.
Full textAbstract:
Leung, Chi Yin.Thesis (M.Phil.)--Chinese University of Hong Kong, 2013.
Includes bibliographical references (leaves 81-89).
Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web.
Abstracts also in Chinese.
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Santagata, Nancy Marie. "Stereochemical effects on the organizational and electronic structure of the tartaric acid/Ag(111) system." 2009. http://www.lib.ncsu.edu/theses/available/etd-05272009-113006/unrestricted/etd.pdf.
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Bali, Amit K. "Alkynones Derived from Tartaric Acid : Efficient Building Blocks for the Synthesis of Macrolactone Natural Products." Thesis, 2017. http://etd.iisc.ac.in/handle/2005/3790.
Full textAbstract:
The thesis describes the synthesis and application of various alkynones derived from the bis-Weinreb amide of tartaric acid in the total synthesis of macrolactone natural products. The thesis is divided into three sections.
First section of the thesis describes the optimization and generalization of the procedure for the addition of alkynyl Grignard / lithium reagents to the bis-Weinreb amide derived from tartaric acid to yield the mono alkynyl ketones was developed. Application of the formed γ-oxo amides was demonstrated in the synthesis of polyols with varied substitutions particularly the synthesis of 1,2,4-triols was accomplished using Ley’s dithianylation as the key step.
Scheme 1: Synthesis of polyols from the bis-weinreb amide of tartaric acid.
Application of the strategy to the total synthesis of decanolactone natural products achaetolide and (Z)-isomer of (6S,7R,9R)-6,7-dihydroxy-9-propylnon-4-eno-9-lactone was featured.
Section B of the thesis deals with the enantiospecific total synthesis of 14-membered macrolactone Sch 725674.
Key reactions in the synthesis include the synthesis of the 1,2,4-triol unit from tartaric acid, olefin cross metathesis and ring closing metathesis.
Scheme 4: Enantiospecific total synthesis of Sch 725674.
Section C of the thesis describes the enantiospecific synthesis of the C9-C22 fragment of the 28-membered polyene polyol macrolide pentamycin. Although isolated in 1958, total synthesis of this antifungal compound was not reported.
In application of the methodology developed, the alkynone prepared from the bis-Weinreb amide was elaborated to the required fragment.
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Bali, Amit K. "Alkynones Derived from Tartaric Acid : Efficient Building Blocks for the Synthesis of Macrolactone Natural Products." Thesis, 2017. http://etd.iisc.ernet.in/2005/3790.
Full textAbstract:
The thesis describes the synthesis and application of various alkynones derived from the bis-Weinreb amide of tartaric acid in the total synthesis of macrolactone natural products. The thesis is divided into three sections.
First section of the thesis describes the optimization and generalization of the procedure for the addition of alkynyl Grignard / lithium reagents to the bis-Weinreb amide derived from tartaric acid to yield the mono alkynyl ketones was developed. Application of the formed γ-oxo amides was demonstrated in the synthesis of polyols with varied substitutions particularly the synthesis of 1,2,4-triols was accomplished using Ley’s dithianylation as the key step.
Scheme 1: Synthesis of polyols from the bis-weinreb amide of tartaric acid.
Application of the strategy to the total synthesis of decanolactone natural products achaetolide and (Z)-isomer of (6S,7R,9R)-6,7-dihydroxy-9-propylnon-4-eno-9-lactone was featured.
Section B of the thesis deals with the enantiospecific total synthesis of 14-membered macrolactone Sch 725674.
Key reactions in the synthesis include the synthesis of the 1,2,4-triol unit from tartaric acid, olefin cross metathesis and ring closing metathesis.
Scheme 4: Enantiospecific total synthesis of Sch 725674.
Section C of the thesis describes the enantiospecific synthesis of the C9-C22 fragment of the 28-membered polyene polyol macrolide pentamycin. Although isolated in 1958, total synthesis of this antifungal compound was not reported.
In application of the methodology developed, the alkynone prepared from the bis-Weinreb amide was elaborated to the required fragment.
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Melino, Vanessa Jane. "Ascorbate metabolism in grape berries during development." Thesis, 2010. http://hdl.handle.net/2440/68714.
Full textAbstract:
Ascorbate (Asc, Vitamin C) is a ubiquitous and abundant antioxidant in plants. The biological role of Asc is composed of the following three functions: as an antioxidant (radical scavenger), an enzyme cofactor and a donor/acceptor in electron transport across membranes. This present research was focussed on the additional, less comprehensively investigated function of Asc as a precursor of tartaric acid (TA) and oxalic acid (OA) in certain species. Although the in planta function of TA is unclear, it is well known as the dominant organic acid in grape (Vitis vinifera) berries. TA is therefore largely responsible for the low berry pH, whereas in other fruits, the majority of the acidity is conferred by malic, citric and ascorbic acids. Earlier research investigating the Asc-derived TA biosynthetic pathway revealed several intermediates and one characterised enzyme. Research investigating metabolism of the Asc precursor in TA and OA accumulating plant species is now required. The aim of this present research was to therefore investigate the factors which may regulate the accumulation of Asc and those which in turn regulate the fate of Asc in fruit. Sensitive methods were developed for the extraction and analysis of Asc, TA and OA from vegetative and fruit tissues. These methods were used to demonstrate that Asc and its catabolites are widely distributed throughout the grapevine; however, the total Asc pool and the Asc to dehydroascorbic acid (DHA) ratio were shown to be significantly greater in leaves than berries at all physiological stages of maturity. This research further demonstrated that immature grape berries rapidly accumulate Asc in situ from D-mannose and L galactose (precursors of the Smirnoff-Wheeler Asc biosynthetic pathway). Developmental regulation of Asc biosynthetic, recycling (redox) and catabolic genes were demonstrated in grape berries. The gene transcription results of this study strongly suggested that Asc biosynthesis in immature berries is supported by the Smirnoff-Wheeler biosynthetic pathway whilst the alternative 'carbon-salvage' pathway of Asc biosynthesis supports post-veraison accumulation of Asc. A positive correlation between the developmental accumulation of Asc and TA was observed and the capacity for in situ Asc catabolism in immature berries, generating both TA and OA products, was directly demonstrated. The accumulation of Asc and TA was shown to be influenced by sunlight intensity and, putative light-responsive Asc biosynthetic and recycling genes were identified. The results also demonstrated that OA accumulates in berries independent of sunlight intensity. The outcomes of this research strongly suggested that TA biosynthesis is regulated by the availability of its precursor Asc; however, it is unlikely that the biosynthesis of OA is dependent on the availability of Asc. In conclusion, the results of this present study highlighted that both developmental and environmental factors influence transcription of Asc metabolic genes and the accumulation of Asc. Furthermore, these factors also influence the fate of Asc in grape berries. The low levels of accumulated Asc detected in the fruit at all stages of maturity are therefore likely to be the result of catabolism rather than a low biosynthetic capacity. The implications of Asc catabolism and the accumulation of TA and OA products on fruit growth and development are discussed.Thesis (Ph.D.) -- University of Adelaide, School of Agriculture, Food and Wine, 2010
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Metri, Prashant K. "β-Keto Phoshonates from Tartaric Acid in the Total Synthesis of (+)-4-epi-gabosine A, (+)-dihydrokawain-5-ol, (-)-bengamide E and indetification of MPK-09 : A Small Molecule that Restores the Wild type Function of Mutant p53." Thesis, 2014. http://etd.iisc.ac.in/handle/2005/4101.
Full textAbstract:
The thesis entitled “-Keto phosphonates from tartaric acid in the total synthesis of ()-4-epi-gabosine A, ()-dihydrokawain-5-ol, ()-bengamide E and Identification of MPK-09: A small molecule that restores the wild type function of mutant p53.’’ demonstrates the utility of -keto phosphonate derived from tartaric acid as a building block in the synthesis of bioactive natural products small molecules of therapeutic importance. The thesis is divided into three sections.
Section I of the thesis deals with the utility of new -keto phosphonate 1, derived by desymmetrization of bis-Weinreb amide of L-(+)-tartaric acid (Scheme 1).
Scheme 1: (a) MeP(O)(OMe)2, n-BuLi, THF, –78 ˚C, 1.5 h, 91%.
A series of functionalized aldehydes were used in the Horner-Wadsworth-Emmons type reaction of phosphonate 2. Under the optimized condition, a series of aldehydes including aryl, aliphatic aldehydes with chiral centers next to the aldehyde functionality underwent facile olefination to yield the , unsaturated ketones in good yields (Scheme 2).
Scheme 2. (a) Cs2CO3, aldehyde, iPrOH, rt, 1 h.
Application of the synthesized unsaturated ketones in the synthesis of various molecular architectures of therapeutic importance was undertaken. Application of this strategy in the total synthesis of (+)-4-epi-gabosine A and (+)-dihydrokawain-5-ol is delineated.
The -keto amides were reduced with good diastereoselectivity with NaBH4 to afford the -hydroxy amide which was transformed to the diene. Ring closing metathesis of the diene led to the cyclohexenone which on deprotection gave ()-4-epi-gabosine A (Scheme 3). The key reactions during the synthesis are Horner-Wadsworth-Emmons reaction, stereoselective reduction and ring closing metathesis as shown in Scheme 3.
Scheme 3: Stereoselective total synthesis of ()-4-epi-gabosine A.
Dihydrokawain-5-ol 11 is a unique 6-alkyl-5-hydroxy-5,6-dihydropyran-2-one isolated from the methanol extracts of the kava plant (Piper mythisticum), a Polynesian shrub of the pepper family and exhibits promising biological activities. Stereoselective total synthesis of this natural product from tartaric acid is described in this section. Key features of the synthesis include the elaboration of the unsaturated ketone obtained from the phosphonate to the allylic alcohol 8 and further elaboration to the natural product 11 as depicted in Scheme 4.
Scheme 4: Total synthesis of (+)-dihydrokawain-5-ol.
(Part of this work has been communicated).
Section II of the thesis deals with the enantiospecific total synthesis of ()-bengamide E. Bengamide E was isolated from the jaspidase sponges by the Crew research group. Enantiospecific total synthesis of bengamide E was accomplished in 8.5% overall yield in a linear sequence of 10 steps starting from the bis-(dimethylamide) unit of tartaric acid as chiral pool precursor (Scheme 5). Key features of the synthesis includes combination of the addition of 1, 3-dithian-2-yllithium, stereoselective reduction and Horner-Wadsworth-Emmons reaction.
Scheme 5: Enantiospecific total synthesis of bengamide E.
(This work has been published: Metri, P. K.; Schiess, R.; Prasad, K. R. Chem. Asian. J. 2013, 8, 488).
Section III of the thesis deals with MPK-09 and a series of novel lactones, structurally similar to bioactive styryllactones synthesized from tartaric acid and studied their in vitro ability to inhibit the growth and induce apoptosis in human tumor cell lines. It was found that MPK-09 a small molecule in the series is more cytotoxic towards cancer cell lines harboring p53 mutation E285K and R273C. Ectopic expression of p53 plasmids harboring various hotspot mutations, demonstrated that MPK-09 was more effective on the tested p53 mutants compared to the wt p53 harboring cells. The restoration of p53 function was further corroborated by the transactivation of its pro-apoptotic signaling pathways as shown by the induction of p21 and Bax protein expression by western analysis. It was demonstrates that the activity was due to the restoration of the wild type conformation of mutant p53.
(Part of this work is published: Metri, P. K.; Naz, S.; Kondaiah, P.; Prasad, K. R. ACS Chem. Biol. 2013, 8, 1429).
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Ambardekar, Amogh. "Modifications in visco-elasticity of gluten diacteyl tartaric acid ester of monoglyceride (DATEM), ascorbic acid, urea and dithiothreitol and its effects on mixing and baking properties in commercial wheat flours." 2009. http://digital.library.okstate.edu/etd/Ambardekar_okstate_0664D_10538.pdf.
Full text
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Stern, Ben, Carl P. Heron, T. Tellefsen, and M. Serpico. "New investigations into the Uluburun resin cargo." 2008. http://hdl.handle.net/10454/4797.
Full textAbstract:
Resin found within Canaanite amphorae from the Late Bronze Age shipwreck discovered off the coast of southwest Turkey at Uluburun has previously been identified as Pistacia sp. Although evidence from Egypt suggests that this resin was in high demand and typically transported in such amphorae, it has also been proposed that the amphorae contained wine, with the resin used to seal the interior surfaces and to flavour and/or preserve the wine. To attempt to resolve this question, we have analysed five samples of pistacia resin found in amphorae from the shipwreck using a range of analytical techniques which have used in the past for the analysis of wine residues: spot tests, FT-IR, and HPLC-MS-MS. As well as the archaeological samples, we have analysed modern samples of pistacia resin, leaves and fruit to determine the effectiveness of each technique and to exclude the possibility of false positive results. In addition to the analyses for wine we also detail analysis (GC-MS) of the terpenoids for the purpose of further molecular characterisation of the resin. Bulk stable isotope analysis was used in comparison with similar resins to attempt to identify the geographical origin of the resin.
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Buckler, Joshua Neil Victor Timshell. "Stereoselective Syntheses of Certain Natural Products and their Analogues from Chiral-pool and Enzymatically-derived Building Blocks." Phd thesis, 2017. http://hdl.handle.net/1885/146534.
Full textAbstract:
This thesis is comprised of six scientific articles and is
preceded by an overview that contextualises all of this
published/submitted work.
The first section of this thesis is comprised of Publications 1-3
and is concerned with the synthesis of novel, oxygenated
analogues of the natural and non-natural enantiomeric forms of
the Amaryllidaceae alkaloid galanthamine, a reversible and
selective acetylcholine esterase (AChE) inhibitor that is used
clinically in the treatment of Alzheimer’s disease.
Specifically, Publication 1 is an invited book chapter that
details synthetic approaches to galanthamine and certain
analogues pursued by the Banwell Group. It contextualises the
strategy employed in preparing oxygenated analogues of
galanthamine by the author in latter part of the first section of
this thesis.
Publication 2 is an invited review article that showcases the
methodologies that have been developed within the Banwell Group
for manipulating enzymatically-derived and homochiral
cis-1,2-dihydrocatechols so as to generate a significant range of
biologically active natural products.
Publication 3 describes the synthesis of certain oxygenated
derivatives of both (+)- and (–)-galanthamine and the
evaluation of these as AChE inhibitors.
The second section of this thesis is comprised of Publications 4
and 5. These detail the synthesis of certain polyfunctionalized,
cyclohexene-based chirons from L-(+)- and D-(–)-tartaric acid,
respectively, and their elaboration into various natural product
scaffolds.
Specifically, Publication 4 describes the preparation of the
aforementioned chirons from L-(+)-tartaric acid and its
elaboration to the enantiomer of a key intermediate described in
Publication 3 that is used to produce oxygenated analogues of
(–)-galanthamine.
Publication 5 further demonstrates the utility of these new
chirons in total synthesis by employing the enantiomer of this
chiron (prepared from D-(+)-tartaric acid) as a key intermediate
in the first total synthesis of the structurally unusual natural
product aspergillusol B.
The final section of this thesis is comprised of Publication 6.
This details work on the total synthesis of the four
diastereomeric forms of the pro-angiogenic guaiacylglycerol
8-O-4ʹ-coniferyl ethers (GGCE) in an effort to establish the
role stereochemistry plays on their capacities to act as
pro-angiogenic agents.
The syntheses feature an Evans/Seebach syn-aldol reaction
utilising auxiliaries derived from either L-(+)- or
D-(–)-valine. In the case of syntheses of the anti-compounds
this was followed by a Mitsunobu inversion of the benzylic
alcohol. The four diastereomers were assessed for their
pro-angiogenic properties in a human microvascular endothelial
cell tubule assay. Whilst they were all active, the compounds
containing the 8S-ether linkage were the most potent.
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Singh, Piyal. "Stereoselective synthesis of functionalized allenes, total synthesis of monticolides A and B, and towards the total synthesis of tulearin C." Thesis, 2021. https://etd.iisc.ac.in/handle/2005/5551.
Full textAbstract:
The thesis, entitled as “Stereoselective synthesis of functionalized allenes, Total synthesis of Monticolides A and B, and towards the total synthesis of Tulearin C” is divided into two chapters.
Section A chapter-1 deals with the stereoselective synthesis of functionalized allenes from tartaric acid. Desymmetrization of the C-2 symmetric bis-dimethylamide derived from tartaric acid by addition of alkynyl Grignard / lithium reagents to yield the mono alkynyl ketones was achieved in good yield. Stereoselective Luche reduction of the mono alkynyl ketones furnished the corresponding alcohols which were transformed to allenes using Claisen rearrangement. Application of the allenes was demonstrated in the synthesis of the polyhydroxy unit of the natural product anamarine and in the synthesis of one of the THP units of the natural product sorangicin.
(Part of this work has been published: Shruthi, K. S.; Singh, P.; Prasad, K. R. Tetrahedron 2020, 76, 131706).
Section B of chapter-1 describes the total synthesis of monticolides A and B, -pyrone containing natural products. Key step in the synthesis include iridium catalysed redox reaction of the Achmatowicz reaction product obtained from the furyl carbinol. The furyl carbinol was obtained by elaboration of the bis-Weinreb amide.
(Part of this work has been published: Singh, P.; Prasad, K. R. Tetrahedron, 2021, 84, 132004).
Section C of chapter-1 is concerned with synthesis of the THF unit of the natural product trans-solamin from the bis-Weinreb amide derived from tartaric acid. Key step for the synthesis of the trans-THF unit is the cobalt catalysed Mukaiyama oxidative cyclization of the butenyl alcohol derived from bis-Weinreb amide. Boord olefination followed by olefin cross metathesis reaction/ hydrogeantion were employed for the synthesis of the intermediate, the conversion of which to trans-solamin is reported in literature, thus constituting a formal synthesis.
Section D of chapter-1 of the thesis discloses the enantiodivergent synthesis of 2-epi-noviose from the bis-Weinreb amid. Pivotal steps in the synthesis include Wacker type oxidation reaction.
Second chapter of the thesis describes the efforts towards the total synthesis of the macrolactone tulearin C. The synthesis of C3-C13 portion of tulearin C was accomplished from the allyl alcohol using Claisen rearrangement reaction. Alcohol was prepared which in turn was synthesized from the bis-Weinreb amide.
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Sá, Maria Manuela Gonçalves de. "Estratégias enológicas na gestão do processo de vinificação e estabilização." Master's thesis, 2020. http://hdl.handle.net/1822/72436.
Full textAbstract:
Dissertação de mestrado em Tecnologia e Ciência AlimentarO presente trabalho foi elaborado no âmbito da dissertação de Mestrado em Tecnologia e Ciência Alimentar nas Caves Campelo S.A., e teve como principal objetivo acompanhar o processo completo de vinificação em vinhos verdes, nomeadamente das castas Alvarinho, Loureiro e Arinto. Pretendeu-se avaliar diferentes métodos de filtração e diferentes estabilizantes tartáricos de modo a obter os resultados mais benéficos para a empresa, efetuando-se ensaios de filtração e de estabilização tartárica. No primeiro caso, analisaram-se os parâmetros físico-químicos e por consequente a medição da turbidez no vinho não filtrado, procedendo-se em análise comparativa dos valores de turbidez e dos parâmetros FQ com os outros dois métodos em estudo, filtração por placas e por terras. Sendo a presença de cristais um dos fatores de rejeição do vinho por parte do consumidor, os ensaios de estabilização tartárica centraram-se na adição de ácido metatartárico e de carboximetilcelulose (CMC), analisando o efeito de cada um deles e o impacto nos parâmetros físico-químicos e sensoriais. Paralelamente à medição da condutividade elétrica (teste minicontacto) da CMC e do ácido metatartárico realizou-se um teste frio, no qual se monitorizaram os resultados durante trinta dias. A análise sensorial é um dos pontos cruciais quer na produção quer na sua aceitação do vinho. Para o efeito, as amostras foram provadas por um painel de cinco provadores. Os resultados obtidos permitiram concluir que os métodos de filtração testados conferem resultados satisfatórios surgindo, porém, alterações em determinados parâmetros físico-químicos. É possível inferir que a CMC e o ácido metatartárico previnem a precipitação tartárica, no entanto, o ácido metatartárico apresenta resultados mais vantajosos nas três castas. A adição dos estabilizantes tartáricos não evidenciou diferenças significativas nos parâmetros físico-químicos. A nível sensorial é possível verificar que cada casta apresenta um comportamento distinto face aos diferentes métodos de filtração/adição dos estabilizantes tartáricos.
The present work was carried out in the form of a curricular internship at Caves Campelo S.A. and its main objective was to follow the complete vinification process of vinhos verdes, namely Alvarinho, Loureiro and Arinto. The goal was to evaluate diferente filtration methods and different tartaric stabilizers in order to ascertain which one would yield the most beneficial results for the company. Accordingly, triplicate filtration and tartaric stabilization tests were performed. In the first case, the physicochemical parameters were analyzed, turbidity was measured in unfiltered wine and a comparative analysis of turbidity and CF parameters was conducted through plate filtration and Diatomaceous earth. Considering the presence of crystals is one of the factors of wine rejection by the consumer, the tartaric stabilization tests focused on the addition of metatartaric acid and carboxymethylcellulose (CMC), analyzing their effect and impact on the physical and chemical and sensory parameters. In parallel with the electrical conductivity (mini-contact test) measurement of CMC and metatartaric acid, a cold test was performed and the results were monitored for a period of thirty days. Sensory analysis of wines is one of the crucial points in both wine production and acceptance. To this purpose, the samples were tested by a panel of five tasters and the descriptive characteristics were evaluated on a radar diagram and the final evaluations on a bar graph. The results allow to conclude that plate filtration provides better wine clarification, although some alterations in certain physicochemical parameters may occur. It could also be inferred that CMC and metatartaric acid prevent tartaric precipitation. However, metatartaric acid shows more advantageous results in the three varieties tested. The addition of tartaric stabilizers revealed no significant differences in physicochemical parameters. At the sensory level, it can be concluded that each wine variety reacts differently to the filtration/addition methods of tartaric stabilize.
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Kumar, S. Mothish. "Total Synthesis of Bio-active Natural Products Gabosines, Crassalactone C, Anamarine and Iriomoteolide 3a." Thesis, 2014. http://etd.iisc.ac.in/handle/2005/2960.
Full textAbstract:
First chapter of the thesis describes the desymmetrization of the bis-dimethyl amide 1 derived from tartaric acid with vinyl Grignard reagents and subsequent reduction of the resultant -keto amides 2a-c to the -hydroxy amides 3a-c. Application of the -hydroxy amides 3a-c in the total
synthesis of bio-active natural products such as gabosines, crassalactone C and anamarine is described in the subsequent sections. In section A of the first chapter, application of the -hydroxy amides 3a-b to the total synthesis of gabosine A 4, gabosine F 5 and gabosine H 6 was described. Key strategy in the synthesis was the use of ring closing metathesis (RCM) reaction. Incidentally, the total synthesis of
gabosine H 6 was not only accomplished for the first time but the synthesis also ascertained the absolute stereochemistry of the natural product. During the course of the synthesis of gabosine A 4,
an unprecedented formation of a unique 14-membered macrocycle 7 was observed. Incisive studies were conducted to elucidate the reaction sequence for the formation of the macrocyle 7. It was found that the formation of the macrocycle 7 was through a tandem cross-metathesis/intramolecular hetero
Diels-Alder reaction. Section B of chapter 1 delineated the utility of the -hydroxy amide 3a in the total synthesis of
(–)-crassalactone C 8a. Crassalactone C 8a is a cinnamoyl derivative of styryllactone natural product goniofufurone and was found to possess marginal in vitro cytotoxic activity. Pivotal strategies in the
synthesis include the use of bis-cinnamoyl ester 10a in the ring closing metathesis reaction which also evades the selective cinnamoylation of the benzylic hydroxy group. Section C of Chapter 1 deals with the total synthesis of (+)-anamarine 11. While the - hydroxy amide 3a was employed to synthesize an important intermediate 12 enroute to the synthesis of anamarine, to mitigate the number of steps in the synthesis, the -hydroxy amide
13 was employed for the synthesis of (+)-anamarine 11. Key reactions in the total synthesis include the use of 1,3-dithiane as a surrogate for the methyl group, Brown’s allylation and ring closing metathesis. In second chapter of the thesis, formal total synthesis of iriomoteolide 3a 16 is presented.
Iriomoteolide 3a 16 is a unique 15-membered marine macrolide isolated by Tusda’s group from the Amphidinium strain HYA024, with impressive in vitro cytotoxic activity against human lymphoma cell line DG-75 (IC50 0.08 g/mL) and Raji cells (IC50 0.05 g/mL). Salient features of the synthesis
include the synthesis of the chiral aldehyde 19 from the oxazolidinone 17 and the use of -keto phosphonate 20 derived from D-(–)-tartaric acid in the Horner-Wadsworth-Emmons olefination reaction to construct the C1-C10 fragment 23 of iriomoteolide 3a 16. Synthesis of the C10-C18 fragment 29 was accomplished from the butyrolactone 24 using
Keck allylation and olefin cross metathesis reactions as key steps. Ring closing metathesis of the ester 30, followed by selective deprotection of the primary TBS group afforded the key intermediate 31,
the transformation of which to iriomoteolide 3a 16 is known in literature.