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1
Hunter, Stuart James. "Synthesis and Exploitation of Branched Sugars and Sugar Amino Acids." Thesis, University of Oxford, 2007. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.491619.
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This thesis describes the synthesis of 2-C-branched carbohydrate derivatives from ketohexoses and some useful synthetic applications thereof. Chapter 1 encompasses a general introduction to branched-chain sugars, with the emphasis upon 2C- hydroxymethyl and -methyl branched sugars. Strategies for their synthesis are discussed, both from nucleophilic and electrophilic carbohydrate derivatives. Some synthetic applications of carbohydrates and consequently branched carbohydrates are highlighted, with a view to the derivatisation of a proposed chiron from the Kiliani ascension of L-sorbose, 2-C-hydroxymethyl2,3: 5,6-di-O-isopropylidene-L-gulono,1,4-lactone. In chapter 2, the Kiliani ascension of L-sorbose and two subsequent complementary di-O-isopropylidene protections of the branched-chain lactones generated (thermodynamic and kinetic) are discussed. Further studies into the same transformations of three other ketohexoses, D-fructose, D-tagatose and D-psicose are then discussed. Further useful synthetic derivatives of the three major isomeric L-sorbose-derived branched di-protected lactones: selective deprotections and cleavage of C5-C6 bonds. One major area wh!ch utilizes carbohydrate building blocks is iminosugar synthesis. Iminosugars are the major compound class of interest in the realm of glycosidase inhibition, and also have other therapeutic properties, thus making them desirable synthetic targets. The application of 2-C- . branched sugar derivatives in the synthesis of novel iminosugars is proposed. Chapter 4 describes the syntheses of eight novel 2-C- hydroxymethyl and -methyl branched iminosugars from the major thermodynamic product (2-C-hydroxymethyl-2,3 :5,6-di-O-isopropylidene-L-gulono-l ,4-lactone) obtained from the Kiliani ascension of L-sorbose, as described in chapter 2. The syntheses of two additional novel iminosugars from isomeric 2,3:5,6-di-O-isopropylidene branched derivatives is described. Some results of inhibitory activity follow the synthetic results. The last two chapters provide a general introduction to macrocycles, and some synthetic investigations into macrocycles based on open-chain sugar amino acids (SAAs). SAA-derived macrocycles are structural hybrids of macrocyclic peptides and cyclodextrins. Strategies for the synthesis of large rings and previous work on D-galactose-derived-SAA macrocycles within the group is described with a view to the extension of this work towards novel asymmetric macrocycles with functionalisable rings. Chapter 6 reports synthetic investigations into three related families of macrocycles, each based on an open-chain galacto SAA. The pure galacto SAA macrocycles are revisited and two novel families of macrocycles are born, one containing proteinogenic amino acids and the other incorporating branched-chain SAAs. The branched-chain SAA itself is derived from 2-C-hydroxymethyl-2,3 :5,6-di-O-isopropylidene-D-mannono-l ,4-lactone, the major protected Kiliani lactone derived from D-fructose. Two major improvements to the original methodology for macrocycle formation are reported. Some structural analysis of macrocylic compounds through NMR and CD spectroscopy.
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Thomas, Albert. "Synthetic routes to amino sugars from 2,3-unsaturated sugars /." The Ohio State University, 1985. http://rave.ohiolink.edu/etdc/view?acc_num=osu1487262513409407.
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Hsia, Kenneth Y. "Carbocycles from sugars." Thesis, University of Oxford, 1994. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.260126.
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Szarek, Mark Anthony. "Chemistry and biology of novel amino sugars and amino-sugar analogs." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1998. http://www.collectionscanada.ca/obj/s4/f2/dsk2/ftp03/NQ31955.pdf.
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PITTIA, PAOLA. "Physical state of sugar matrices and aroma-sugars interactions at nanoscale." Doctoral thesis, Università degli Studi di Trieste, 2016. http://hdl.handle.net/11368/2908096.
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Hemmings, Philippa Rachel. "Nitrogen heterocycles from sugars." Thesis, University of Oxford, 1992. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.314823.
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Beacham, Annabel R. "Studies on higher sugars." Thesis, University of Oxford, 1994. http://ora.ox.ac.uk/objects/uuid:a392cc72-9ff2-43cf-a9c4-38f16df261ff.
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This thesis describes the synthesis of three novel seven carbon bicyclic mimics of α-L-fucose, and of two new pyrrolidine amino sugars. 2,7-Anhydro- l-deoxy-β-L-gulo-heptulopyranose and l,2,7-trideoxy-2,7-imino-β- L-gulo-heptulopyranose were both synthesised from L-gulono-l,4-lactone. The addition of one equivalent of methyllithium to the diacetonide of L-gulono-1,4- lactone gave a keto-sugar, l-deoxy-3,4;6,7-di-0-isopropylidene-β-L-gulo- heptulofuranose. The anomeric configuration of this compound was determined by equilibrium nOe measurements. Hydrolysis in aqueous trifluoroacetic acid caused simultaneous deprotection, isomerisation and dehydration to yield 2,7-anhydro-l-deoxy-β-L-guloheptulopyranose, a highly stable, rigid bicyclic system. The structure of the bicyclic system was confirmed by X-ray crystallographic studies on a crystalline derivative. The introduction of nitrogen at C-6 of L-gulono-l,4-lactone was achieved via the azide displacement of the known bromide, 6-bromo-6-deoxy-2,3-0- isopropylidene-L-gulono-l,4-lactone. Protection of the C-5 hydroxyl group as its silyl ether was followed by the addition of one equivalent of methyllithium to the carbonyl group to give a keto-sugar, 7-azido-6-(0-tert-butyldimethylsilyl-l,7- dideoxy-3,4-0-isopropylidene-β-L-gulo-heptulofuranose. Removal of the protecting groups followed by reduction of the azide functionality gave the bicyclic hemiaminal, l,2,7-trideoxy-2,7-imino-β-L-gulo-heptulopyranose, a stable but hygroscopic solid. A third bicyclic system, 2,7-anhydro-l,2,6-trideoxy-2,6-imino-β-L-gulo- heptulopyranose, was synthesised from diacetone-D-mannose via the known ketosugar, 6-azido-7-0-tert-butyldimethylsilyl-l,6-dideoxy-3,4-0-isopropylidene-β- L-gulo-heptulofuranose. Removal of the protecting groups from this keto-sugar, followed by reduction of the azide functionality, gave the target system. Analysis of the NMR spectra showed that this existed as an equilibrium mixture of the closed, bicyclic hemiaminal form and the monocyclic imine form, with the bicyclic form predominating in all solvents investigated. The sodium borohydride reduction of l-deoxy-3,4;6,7-di-0-isopropylidene-β-L-gulo-heptulofuranose gave a single product, the heptitol 7-deoxy-l,2;4,5-di-0-isopropylidene- L-glycero-D-gluco-heptitol. This was converted into two novel pyrrolidine amino sugars, l,2,5-trideoxy-2,5-imino-L-glycero-L-allo-heplitol and l,2,5-trideoxy-2,5-imino-L-allitol. The two free hydroxyl groups in the heptitol were converted into leaving groups and one was then displaced selectively with sodium azide. Reduction of the azide functionality gave an amine which cyclised onto the remaining leaving group to form the pyrrolidine framework. Complete deprotection of this product gave l,2,5-trideoxy-2,5-imino-L-glycero-L-allo- heptitol, the structure of which was confirmed by X-ray crystallographic studies on a crystalline derivative. Removal of the primary acetonide from the cyclisation product and subsequent periodate cleavage gave an aldehyde which was then reduced to an alcohol. Deprotection then gave the second pyrrolidine amino sugar l,2,5-trideoxy-2,5-imino-L-allitol. The effect of all five target compounds on eleven human liver glycosidase enzymes was investigated, and these results are also reported.
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Pornpakakul, Surachai. "Synthesis of carba-sugars." Thesis, University of Manchester, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.683737.
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Fujii, Sachie. "Studies on drying of sugar solutions and stabilization of dried foods by sugars." Kyoto University, 2014. http://hdl.handle.net/2433/189644.
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Elliott, Russell Phillip. "Sugars as homochiral starting agents." Thesis, University of Oxford, 1992. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.316887.
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Hindle, Neil. "Amino sugars and their glycosides." Thesis, University of Oxford, 1995. http://ora.ox.ac.uk/objects/uuid:78ab400f-4a4c-47bb-9d18-1b3bef205044.
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This thesis describes approaches to the transformation of simple carbohydrates into a polyhydroxylated pyrrolidine and the formation of its glucosides. Chapter one describes the synthesis of the naturally occurring pyrrolidine 2,5-dideoxy-2,5-imino-D-mannitol. Synthesised from di-O-isopropylidene-D-glucose, the key steps are the introduction of nitrogen at C-5 with retention of configuration. Then cyclisation of the nitrogen onto the C-2 position with inversion to form the pyrrolidine ring. Reduction of the aldehyde furnished the polyhydroxylated heterocycle in 3.4% yield over 16 steps. The synthetic compound matched the naturally occurring compound in all respects. Chapter two contains a review of commonly used glycosylation methods. It also describes the glycosylation of di-O-isopropylidene-α-D-glucose as a model system comparing the Koenig-Knorr method to the trichloroacetimidate method using several reaction conditions. Glycosylation of 2,5-dideoxy-2,5-imino-D-mannitol was carried out using the trichloroacetimidate method to synthese all four glucosides. Boron trifluoride etherate and trimethylsilyl trifluoromethanesulphonate were used as catalysts in dichloromethane, diethyl ether and acetonitrile under strictly anhydrous conditions. All four glucosides were prepared 1-O-(αβ-D-glucopyranosyl)-2,5-dideoxy-2,5-imino-D-mannitol and 3-O-(αβ-D-glucopyranosyl)-2,5-dideoxy-2,5-imino-D-mannitol. Biological screening carried out against a wide range of glycosidases and glycosyl transferases indicated that the glucosides showed little inhibition in comparison to 2,5-dideoxy-2,5-imino-D-mannitol. Chapter three describes the isolation and identification of 1-O-(β-D-glucopyranosyl)- 2,5-dideoxy-2,5-imino-D-mannitol from Nephthytis poisonii N.E.Br. a member of the Araceae family found in tropical Africa. Identification was made by comparison with the previously synthesised glucosides of 2,5-dideoxy-2,5-imino-Dmannitol. Investigations of Hyacinthoides non-scriptus (L.) chouard ex Rothm are also discussed. Chapter four describes the synthesis of a diazidolactone that could be used to form a 1,5 disubstituted tetrazole. This would have a second nitrogen functionality in the molecule allowing the possibility of the inclusion of the tetrazole into a peptide sequence. The synthesis was carried out from L-gulono-1,4-lactone. An azido group was introduced selectively at C-2, this unexpectedly occurred with retention of configuration. A second azide was then introduced at C-5, this occurring with the more commonly observed inversion of configuration to afford the 2,5-diazido-2,5-dideoxy-D-manno-1,4-lactone.
12
Dransfield, Paul John. "New routes to imino sugars." Thesis, University of Exeter, 2002. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.247066.
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Goughenour, Kristie. "Histoplasma capsulatum: Drugs and Sugars." The Ohio State University, 2020. http://rave.ohiolink.edu/etdc/view?acc_num=osu1584377509624302.
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Flynn, Claire June. "The synthesis of amino- and diamino-sugars and the evaluation of sugar-dye conjugates." Thesis, University of Nottingham, 2001. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.480978.
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Vargas-Ramirez, Juan Manuel. "Evaluation of Storage Techniques to Preserve Fermentable Sugars from Sugar Beets for Ethanol Production." Thesis, North Dakota State University, 2012. https://hdl.handle.net/10365/26618.
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New sugar beet varieties may qualify as an advanced biofuel feedstock in the U.S., but new alternatives to conventional pile storage are necessary to preserve fermentable sugars and allow yearlong beet ethanol production. Fermentable sugar preservation was assessed in sugar beets stored under aerobic and anaerobic atmospheres and in raw thick juice stored at acidic (2≤ pH≤ 5) and alkaline (8≤ pH≤11) conditions. Aerobic storage of sugar beets at 4°C for 14 wk resulted in higher fermentable sugar retention (99± 4%) than at 25°C or anaerobic storage at 4° C and 25° C. Raw thick juice retained ≥ 99% of fermentable sugars at pH 3.5 and 9.5 and refractometric dissolved solids content of 64.5° Bx. The changes in fermentable sugars in raw thick juice stored for 24 wk at acidic and alkaline pH were modeled by response surface methodology. Although raw thick juice was stored successfully at acidic and alkaline pH, conditions for high-efficiency fermentation must be developed.
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Nazeri, Gelareh. "Formation of Sugars and Organic Acids from Hydrothermal Conversion of Biomass and Biomass-Derived Sugars." Thesis, Curtin University, 2022. http://hdl.handle.net/20.500.11937/89694.
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This study provides new insights into the formation mechanisms of various organic acids from hydrothermal decomposition of biomass under non-catalytic conditions. Firstly, the primary products from hydrothermal decomposition of mallee biomass and its main components are studied. Then, systematic research is undertaken to investigate the formation of various organic acids from hydrothermal decomposition of key intermediates including cellobiose, glucose, fructose and mannose. The reaction pathways of key organic acids from various sugar compounds are revealed.
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Odunlami, Benjamin Oladipo. "The role of sugars and sugar metabolism genes (sucrose synthase) in Arabidopsis thaliana seed development." Thesis, Northumbria University, 2009. http://nrl.northumbria.ac.uk/1687/.
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Seed development in Arabidopsis thaliana, has been studied at several levels. However, little has been done to study the role of sugar metabolism genes in seed pod development in this species. As the fertilized egg progresses to a mature seed, the sugars composition during different stages of the developing changes. These changes are related to metabolic processes in the developing seeds, but also to the activity of sucrose- converting and transporting genes, active at the interphase between the maternal tissue and the endosperm. Sucrose synthase (SUS) is one of these genes; it catalyses the reversible reaction of sucrose breakdown in the presence of UDP to form fructose and UDP-glucose. In this study we looked at glucose, fructose and sucrose concentration at different time points during seed pod development. These changes in sugar concentrations were analysed in both Colombia wild type and WS (Wassilewskija) ecotypes. By comparison of the sugar composition of these ecotypes, and linking these data with phenotypic observations in both ecotypes during development, we are able to comment on the possible role of sugars in seed pod development. Also, the sugar composition of wild type seed pods were compared with those of Atsus mutant seed pods, and possible effects sucrose synthase mutations on the phenotype of the developing Arabidopsis thaliana seeds were analysed. The effect of sucrose synthase knockouts in developing seed pods were studied by comparing biochemical and phenotypic characteristics data of the Atsus mutants within Colombia wild type plants. Salk line plants were screened to identify plants carrying a homozygous insertion for T-DNA in five of the sucrose synthase genes. The developing seed pods of each of the homozygous mutants were characterized biochemically via High-Performance Anion-Exchange Chromatography (HPAEC). Furthermore, seed weight, number of seed per pod, germination rate and the morphological development of the embryo were closely analysed. The study found out that there were some biochemical effects of Atsus knockout mutants, and some phenotypic effects of Atsus knockout mutants on the developing seed pods. However, in general the effects were not as pronounced as those that were seen in maize seed, pea seed and potato tuber as a result of sucrose synthase knockout. The general pattern of glucose, fructose and sucrose were similar to the Colombia wild type, although in mature seed pods the sucrose levels in Atsus1, Atsus2, Atsus3 and Atsus6 were slightly, but significantly lower than in the Colombia wild type.
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Naini, Venkatesh. "Physical and Chemical Stability of Spray Dried Sugars and Protein-Sugar MolecuIar Mixtures for Inhalation." VCU Scholars Compass, 1996. http://scholarscompass.vcu.edu/etd/4982.
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The feasibility of producing inhalable microparticles of sugars and protein-sugar molecular mixtures using spray drying was investigated as an alternative to conventional micronization techniques. Four sugars; lactose (L), trehalose (T), sucrose (S) and mannitol (M) were spray dried using a commercial bench-top spray dryer and their physicochemical stability, with respect to particle size, moisture uptake and crystallinity changes, investigated after storage at 23%, 52%, 75% and 93% relative humidity (RH) and 25 °C for 30 days. Two crystalline size fractions (“coarse” = 125-212 μm and “fine” = 44-74 μm) of each sugar, were also characterized, as possible replacements for lactose as carriers for admixture with drugs in dry powder inhalers (DPIs). Sieve fractions of lactose, trehalose and mannitol failed to show significant moisture uptake at RHs ≤ 93% and 25 °C indicating their thermodynamic stability under most realistic storage conditions. While sucrose failed to show moisture uptake at ≤ 75% RH, it dissolved in sorbed moisture at 93% RH. Spray dried sugars were collected successfully in particle sizes suitable for inhalation. Spray dried lactose, trehalose and sucrose were amorphous and remained in this state after storage at 23% RH. At higher RHs, however, they recrystallized completely in ≤ 30 days. Spray dried mannitol was completely crystalline after collection from the spray dryer. It did not show moisture uptake or physical state changes at all RHs.
A fine particle collection apparatus incorporating a nebulizer and a wire-in-tube type electrostatic precipitator (EP), built and characterized for particle collection efficiency, was used to review protein activity following spray drying with or without the four sugars as stabilizers. Bacterial (BAP) and bovine intestinal alkaline phosphatase (BIAP) were used as model proteins. Sugar free BAP solutions (apparent protein concentration ~120 μg/ml) lost 23% of initial enzyme specific activity after spray drying at ~63 °C and collection in the EP. Protection offered by the sugars to BAP during drying, was however statistically indistinguishable from the sugar-free protein solution (dried from the same protein concentration solution). When BIAP was dried from sugar free solutions (apparent protein concentration ~1 mg/ml), it lost 31% of its initial specific activity; activity which could be completely recovered when BIAP was co-dried with L, T or S (ANOVA, p < 0.05). However, M which crystallized during spray drying failed to protect the enzyme from this loss of activity. These results implied that the physical state of sugar (amorphous or crystalline) in the final dried product may be an important determinant for offering protection to proteins during spray drying and storage. Even so, multiple factors could potentially influence the selection of a sugar to form inhalable microparticles with a protein. These factors are described and discussed in this thesis, whether or not they appeared to be important with respect to the drying and stability of particular proteins selected for experimental investigation.
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Ellenberger, Suzanne Ray. "Total synthesis of selected deoxyamino sugars /." Full text open access at:, 1986. http://content.ohsu.edu/u?/etd,110.
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Mete, A. "Novel nucleoside analogues containing modified sugars." Thesis, City University London, 1985. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.355583.
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Li, Bin. "Innovative Methods for Biomass Sugars Utilization." University of Toledo / OhioLINK, 2012. http://rave.ohiolink.edu/etdc/view?acc_num=toledo1353092448.
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Ehiwe, Tammy Iyobosa. "Investigating the bioprotective properties of sugars." Thesis, University of Greenwich, 2011. http://gala.gre.ac.uk/8076/.
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The purpose of this study was to investigate the stabilizing properties of osmolytes, specifically sugars on biomolecule such as protein. The strategy used in this study involved the utilisation of surfactant-rich micelles; where by the impact sugars have on the free energy of exposure of hydrocarbon groups present within the surfactant micelles was examined. The observation made for sugar-surfactant study was then applied to explain the stabilisation of the native structure and thus the physiologically active form of the protein by sugars. The sugars that have been studied include sucrose, trehalose, maltose, raffinose and mannitol. The surfactants studied were sodium decyl sulphate (SDeS), sodium dodecyl sulphate (SDS) and sodium tetradecyl sulphate (STS). Tensiometry was used to examine the impact of sugars on the critical micelle concentrations (CMC), Gibbs free energy change of micellization ( Gmic), surface pressure, surface excess concentration and area occupied per surfactant molecule. The free energy penalty of hydrocarbon chain exposure was obtained from the Gibbs free energy change of demicellization( Gdemic) which is equal but opposite in sign to the Gmic. Measurements were carried out to elucidate the influence of sugar on the aforementioned surfactant properties as a function of increasing sugar concentration. Isothermal titration calorimetry (ITC) was then used to study -sugar surfactant interactions to give enthalpy ( Hmic) and entropy ( Smic) of micellization in addition to CMC and Gmic, thus obtaining a full thermodynamic characterisation, complementing the results obtained by tensiometry. Tensiometric results revealed that at increasing concentration of sugar, the CMC of the surfactants was decreased and a more negative Gmic was obtained. ITC results revealed a similar trend for the effect of sugar on CMC and Gmic while the Hmic and Smic was increased in the presence of the sugars. The results from surfactant studies suggest an increase in the free energy penalty of hydrocarbon group exposure to the aqueous environment, due to an unfavourable interaction between the hydrophobic groups and the aqueous sugar solution. Consequently, the aggregation process is thermodynamically favoured and more spontaneous in sugar solutions. For instance in SDeS the Gmic in water and in sugar solution showed that micellization was more favourable in sugar solution ( Gmic = -19.14 kJ mol−1 at 1.0M Trehalose) than in water ( Gmic = -18.44 kJ mol−1). In addition, significant increases in surface pressure of the surfactants in the presence of sugars suggest an enhancement of the surface activity of the surfactants. Increases in area occupied per surfactant molecules in the presence of sugars suggest increase in the size of the head group area thus, possible interactions between surfactant head group – sugar or sugar-water mediated interactions. Also increases Hmic in comparison to lower values of Smic obtained by calorimetry suggest possible hydrogen bonding. In conclusion, surfactant studies suggest that sugars would stabilize biological structures by a combination of both an exclusion from the hydrophobic group due to unfavourable interactions between the hydrophobic groups and possible polar interactions between polar groups. Differential scanning calorimetry (DSC) was used to study and characterise the effect of the sugars on the thermal stability of RNase A. The results revealed an increase the thermal stability of RNase A as shown by higher Tm values in the presence of sugars. Results obtained from surfactant studies were then related to DSC results, a linear relationship between the Tm and CMC values suggests a similar mechanism. Hence, though proteins are large complex molecules, their interaction with sugars or other small solutes could be related to simple model systems such as micelles.
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WANG, YI. "Sugar Control of Artemisinin Production." Digital WPI, 2006. https://digitalcommons.wpi.edu/etd-theses/460.
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The role of sugars as regulatory signals has mainly focused on their effects on plant growth, development, gene expression, and metabolism. Little, however, is known about their role in controlling secondary metabolism. Previous work in our lab showed that sugars affect the production of the sesquiterpene antimalarial drug, artemisinin, in hairy roots of Artemisia annua. In this study, sugars alone or in combination with their analogues were used to investigate if sugars control artemisinin production in Artemisia annua seedlings. Compared to sucrose, a 200% increase in artemisinin by glucose was observed. When the glucose analog, 3-O-methylglucose, which is not phosphorylated effectively by hexokinase, was added with glucose, artemisinin production was dramatically decreased but hexokinase activity was significantly increased compared to glucose. In contrast, neither mannose, which can be phosphorylated by hexokinase, nor mannitol, which can not be transported into cells had any significant effect on artemisinin yield. When different ratios of fructose to glucose were added to seedlings, artemisinin yield was directly proportional to glucose concentration. Although addition of sucrose with glucose gave inconclusive results, sucrose analogues decreased artemisinin production compared to sucrose. These results suggested that both monosaccharide and disaccharide sugars may be acting as signal molecules thereby affecting the downstream production of artemisinin. Taken together, these experiments showed that sugars clearly affect terpenoid production, but that the mechanism of their effects appears to be complex.
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Fitzpatrick, L. M. "Transport of sugars across the chloroplast envelope." Thesis, University of Cambridge, 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.599063.
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The aim of the work described in this thesis was to investigate the role and importance of the glucose transporter in the chloroplast envelope. I believed that further characterisation would contribute to our knowledge of transitory starch degradation at night, and to the control of carbon partitioning. I have supplied tracer quantities of [U-14C]glucose and [U-14C]glycerol in the dark to leaves selected from a diverse range of species, and demonstrated that the net flux in the cytosol, during starch degradation in the dark, is glycolytic, so that a gluconegoenic flux from triose-phosphates to sucrose does not occur. This provides evidence that a flucose transporter, rather than the phosphate translocator, is active in the chloroplast envelope for the synthesis of sucrose, and suggests that glucose transport across the chloroplast envelope is found throughout the plant kingdom. I have demonstrated, using the technique of silicon oil centrifugation, that chloroplasts of wild-type Arabidopsis thaliana and tobacco take up glucose but do not take up maltose from the external medium, that glucose transport in Arabidopsis is unaffected by ATP. I have also shown, by pre-labelling starch with 14CO2, that wild-type Arabidoposis chloroplasts export glucose, but not maltose, during starch degradation in the dark. These results imply that maltose is not an important final product of starch degradation in these species. I used transgenic tobacco plants, with altered levels of the triose-phosphate translocater and little impact on carbon fixation, to investigate the role of hexose transport in carbon partitioning. Careful measurements of phosphate and glucose uptake in chloroplasts of antisense and wild-type plants revealed that there was no alteration in glucose uptake, and that the endogenous wild type capacity may be sufficiently high to account for a compensatory flux in glucose transport. I hypothesised that a mutant of Arabidopsis (sex1), with chloroplasts deficient in glucose transport and accumulating starch, did so through increased starch synthesis at night. To support this, I found no differences in the maximal catalytic activities of amylases, starch phosphorylase, phosphoglucomutase, glucokinase and phosphofructokinase (ATP) in chloroplasts isolated from dark-acclimated leaves of sex1 and the wild type.
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Tran, Chuong Hao. "Synthesis of pseudo-sugars and related compounds." Thesis, University of Warwick, 1995. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.308507.
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Wu, Luis Eduardo. "Synthesis of unnatural sugars from unsaturated ketones." Thesis, University of Liverpool, 2001. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.368669.
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Young, Anne A. "Nitrile oxide/isoxazoline approach to higher sugars." Thesis, University of Edinburgh, 1990. http://hdl.handle.net/1842/11655.
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The application of nitrile oxide/isoxazoline chemistry towards the synthesis of higher sugars (monosaccharides containing seven or more contiguous carbon atoms) has been investigated. This convergent approach, involving the cycloaddition of sugar derived alkene and nitrile oxide fragments and subsequent manipulation of the resulting isoxazoline, has much of the product stereochemistry preselected. Three ω-unsaturated monosaccharides were chosen for study: the D-glucose-derived six carbon unit (94), its C-3 epimer (102) and a seven carbon alkene, (97), prepared from D-galactose. Benzonitrile oxide was employed in preliminary studies as a model 1,3-dipole to probe the π-facial selectivity of cycloaddition to these alkenes. Cycloadditions with the carbohydrate derived nitrile oxides (117), (121) and (125) were subsequently examined. For alkenes (94) and (97) a high degree of stereoselectivity (typically ca 85:15) favouring the formation of the erythro 2-isoxazoline was obtained. This observation can be rationalised in terms of the 'inside alkoxy effect' proposed by Houk in which the allylic oxygen occupies the inside position in the transition state. D-Ribo-alkene (102) proved to be an exception; cycloaddition with ethoxycarbonylformonitrile oxide (117) occurred with negligible stereoselectivity (51:49). This result demonstrates the role played by the homoallylic oxygen in determining the stereoselectivity. Pd/C mediated reductive hydrolytic cleavage of the 2-isoxazolines unmasked the β-hydroxy ketone functionality of the deoxy-ulose derivatives. Subsequent reduction furnished a pair of separable diastereomeric 1,3-diols, whose stereochemistry was determined by examination of the ^1H n.m.r. spectra of the corresponding isopropylidene ketals. A series of deoxy -octose, -nonose, -decose, -dodecose and -tridecose monosaccharides have been thus prepared. Finally, other aspects of isoxazoline chemistry have been investigated. The reduction of isoxazoline (123) by lithium aluminium hydride afforded the syn-γ-amino alcohol (176) as the only isolated product. Trans α-enones (174) and (175) were synthesised stereospecifically by dehydration of the corresponding β-hydroxy ketones.
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Parry, Loren L. "The synthesis of branched sugars and iminosugars." Thesis, University of Oxford, 2011. http://ora.ox.ac.uk/objects/uuid:2a511d58-f626-4f7e-aebc-f595b147827a.
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Iminosugars, carbohydrate analogues in which nitrogen replaces the endocyclic oxygen, have attracted much interest due to their biological activity. Iminosugars inhibit carbohydrate-processing enzymes, thereby affecting many biological processes. Several iminosugars are licensed drugs, with many more compounds undergoing clinical trials. The main subject of this thesis is the synthesis and evaluation of novel iminosugars, particularly the effects of structural modifications on the biological activity of these compounds. Chapter 1 describes the role of carbohydrate-processing enzymes in the body, and explores the therapeutic applications of iminosugars that arise from their activity against these enzymes. Examples of substituted iminosugars are reviewed, and the effects of substituents on enzyme inhibition are described. Chapter 2 concerns methyl-branched swainsonine derivatives. Swainsonine has shown potential as a cancer treatment through its inhibition of α-mannosidase. The synthesis of (6R)- and (6S)-C-methyl D-swainsonine is described; both compounds were potent and selective α-mannosidase inhibitors (IC50 3.8 μM, 14 μM). Although less active than the parent compound, their selectivity for Golgi mannosidase over lysosomal mannosidase may be more important than the absolute value against the model enzyme. Chapter 3 describes the synthesis of a 2-C-methyl L-fucose derivative. A diastereoselective Kiliani reaction allowed the formation of a single lactone bearing a new quaternary centre. The utility of this intermediate in accessing di-branched iminosugars was explored; however, attempts to introduce nitrogen to the lactone lacked the necessary stereoselectivity. Chapter 4 relates to the synthesis of pyrrolidine iminosugars, specifically methyl amides. Two enantiomeric dihydroxyproline amides were synthesised; the D-proline derivative was a potent β-N-acetylhexosaminidase inhibitor (IC50 values of up to 3.6 μM), but the L-enantiomer was completely inactive. Inhibition of N-acetylhexosaminidases is relevant to the treatment of cancer and lysosomal storage diseases, and this work contributed to a wider project investigating the effects of altered stereochemistry on the biological activity of pyrrolidine amides.
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Uneyama, Emi. "Synthesis of bicyclic difluorinated analogues of sugars." Thesis, University of Leicester, 2007. http://hdl.handle.net/2381/29998.
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This thesis describes the synthesis of gem-difluorinated cyclooctenone analogues using building block approaches based on the RCM with Grubbs' catalysts.;Des- and gem-dialkyl-substituted difluorodienes were synthesised from commercially available trifluoroethanol by dehydrofluorination/metalation, trapping, allylation and [2,3]-Wittig rearrangement successfully.;The gem-difluorinated dienes produced the corresponding difluorinated cyclooctenones smoothly and in good yields. However, a dithioketal-containing diene did not afford any cyclic product. Thorpe-lngold effect was also observed from the concentration study of des- and gem-dimethyl dienes in the RCM reaction. The gem-dimethyl diene cyclised faster than des-dimethyl diene, and the des-dimethyl diene could cyclise only at low concentration (0.001 M).;The cyclooctenone analogues have interesting topological conformations, which were studied by NMR experiments and computational calculations.;The dihydroxylation and stero-controlled epoxidation were developed on unique 8- membered ring molecules. Dihydroxylation reactions gave mixtures of diastereomeric triol products, which underwent transannular collapse to afford bicyclic products. The stereo-controlled epoxidation with methyl(trifluoromethyl) dioxirane gave the corresponding trans-epoxyalcohol in good yields. The epoxides were very stable under acid conditions however, in basic aqueous solution with microwave irradiation, they afforded bicyclic molecules by a transannular reaction via hemiaminal formation next to fluorine atoms. The newly synthesised conformationally locked difluorinated bicyclic molecules are hydrolytically resistant sugar mimics.
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Barker, Kathrine. "Novel di-branched monosaccharides and imino sugars." Thesis, University of Oxford, 2009. http://ora.ox.ac.uk/objects/uuid:5e9ef70b-9213-4c0c-b500-61200a049c1b.
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Branched chain sugars display a varied and valuable range of biological activities. This thesis concerns the synthesis of 3,5-di-C-methyl-D-glucose, a potential inhibitor of glycogen phosphorylase (GP), and therefore a proposed therapeutic agent for type 2 diabetes. Chapter 1 looks at the occurrence of branched sugars in the natural world and current therapies for type 2 diabetes. Inhibition of GP is explored, and the molecular modelling studies which led to the design of the project target. Chapter 1 also looks into the development of new foodstuffs, the chemistry and biochemistry of imino sugars and branched hydroxy proline analogues. In Chapter 2, a range of different approaches to 3,5-di-C-methyl-D-glucose are investigated. Most of the initial investigations were carried out on the L-enantiomer, a readily available test system deriving from 2-C-methyl-D-ribono lactone. 2-C-Methyl-D-ribono lactone is synthesised rapidly from D-glucose in a one-pot reaction; as the key starting material for this work, the scalability of this process was investigated. One of the attempted syntheses of di-C-methyl glucose lead to the development of a route towards 3,5-di-C-methyl fructose, a novel dibranched ketose sugar. It was envisaged that through an enzymatic transformation, it might be possible to produce 3,5-di-C-methyl glucose stereoselectively. Synthesis of both enantiomers of 3,5-di-C-methyl glucose and mannose are reported, alongside results of GPb inhibition studies. Analysis of the preferred ring size of a range of di-C-methyl branched sugars and sugar lactones generated in this work is also presented. Chapter 3 explores the chemistry of 2,4-di-C-methyl-L-arabinono lactone, a key intermediate in the synthesis of 3,5-di-C-methyl-L-glucose. From this lactone a novel deoxy sugar, 2-deoxy-2,4-di-C-methyl-L-arabinono lactone, was generated. Routes towards a selection of imino sugars were explored, resulting in the synthesis of a methyl branched isofagomine analogue. A substituted aziridine was synthesised, from which a route to a di-C-methyl branched piperidine was proposed, and a pyrrolidine. Also presented is a synthesis of a dihydroxy di-C-methyl branched proline analogue. Detailed NMR analysis of several of the sugars generated in this work was carried out by Dr M. Wormald, of the University of Oxford Biochemistry department. The results of these investigations are presented in the Appendix. Throughout this work, the presence of quaternary centres has posed a problem with the assignment of relative configuration. As a result, this work has been greatly supported by X-ray crystallography, and the structures shown herein were wholly generated by me. Several other crystals were run during the course of this work, not all pertaining to these projects, and are provided in the CD appendix.
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Gogar, Ravikumar Leelamchand. "Economic Production of Furans from Lignocellulosic Sugars." University of Toledo / OhioLINK, 2020. http://rave.ohiolink.edu/etdc/view?acc_num=toledo1595977336480846.
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Kishore, P. V. "Studies on fermentation of sugars to glycerol." Thesis(Ph.D.), CSIR-National Chemical Laboratory, Poona, 1985. http://dspace.ncl.res.in:8080/xmlui/handle/20.500.12252/3219.
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SCELFO, SIMONE. "Metal oxides catalysts for the synthesis of value-added chemicals from 2nd generation sugars and sugar derivatives." Doctoral thesis, Politecnico di Torino, 2017. http://hdl.handle.net/11583/2675152.
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The present Ph.D. thesis provides some examples of innovative 2nd generation catalytic processes for the conversion of renewable raw materials into green value-added chemicals. In particular, D-glucose and some its derivatives, all ideally representing waste materials of dedicated biomasses, agricultural residues, or solid organic urban waste exploitation in the biorefinery plant, were converted into useful chemical building-blocks.
After a brief introduction to the topic and the description of the experimental method, each chapter of the work is based on one or more scientific articles either published or submitted. Among the possible catalytic reactions, the hydrogenation, oxidation and hydrodeoxygenation were investigated: for this purpose, several novel catalysts were synthetized, tested and characterized. The catalysts were made from precursor solutions with the incipient wet impregnation method or with the solution combustion synthesis, depending by the catalyst type. The conversion of glucose and some glucose-derivatives was typically performed under gentle operative conditions and in aqueous mean.
Pt-based catalysts were tested for glucose conversion to adipic acid in a two-step process carried out in water solution without any pH control by investigating the effect of a series of supporting materials (active carbon, alumina, silica and ceria). The process consisted in the D-saccharic acid (SacA) production by D-glucose catalytic wet air oxidation followed by a hydrodeoxygenation treatment of SacA to adipic acid (AA) with the same catalyst. The main limit of using Pt for D-glucose oxidation is represented by the catalyst inhibition operated by the first product of the reaction, the gluconic acid (GluA), which prevents the consecutive reaction of SacA formation, but a deeper investigation of the reaction scheme allowed us to assess that over Pt/alumina the consecutive oxidation of gluconic acid to SacA is slightly favored under uncontrolled pH too.We have demonstrated that a 5.2 wt.% Pt on γ-alumina sample, the catalysts presenting the larger amount of strong Brønsted acid sites, was the best material for obtaining SacA (with a molar yield of about 13.5%); afterward, by performing the halogen-promoted hydrodeoxygenation of the resulting solution, the SacA was quantitatively converted into AA (and thus the overall adipic acid molar yield from glucose was about 13.0%).
Effectively, The efficient conversion of common biomass derivatives, as D-glucose, into value-added chemicals has received a great deal of attention in the last few years. Several heterogeneous catalytic systems, characterized by noble metals, have already been investigated for the Catalytic Wet Air Oxidation (CWAO) of derived biomass. Nevertheless, the redox effect of such catalysts on biobased compounds has not been described in detail. In the present thesis, some perovskite type oxides (Fe, Co, Mn) that present high redox properties and stability under hydrothermal conditions have been tested to establish their ability to convert D-glucose into C6 aldaric acid, lactic acid (LacA) and levulinic acid (LevA). The influence of the reaction temperature, and the affinity of the catalysts to hydrogen and oxygen on the distribution of the liquid products have been investigated. In the best conditions, 50.3 mol.% and 69.5 mol.% of lactic and levulinic acid have been obtained by employing LaCoO3 and LaMnO3, respectively. Apart from the oxidative effect, which has led to several oxidation products, a high reductive effect of the catalysts has enabled the conversion of some key intermediates, such as pyruvic acid (PyrA) and hydroxymethylfurfural (HMF), into the desired products. LaMnO3, which has resulted to be the most oxidizable/reducible catalyst over a low temperature range, has shown the best performance of the studied perovskite type oxides; it has been found to promote the conversion of hydroxymethylfurfural to levulinic acid and to give the highest overall molar yield.
Moreover, performing catalysts have been synthetized through incipient wet impregnation and tested for cis,cis-muconic acid (ccMA) hydrogenation to adipic acid.
Before the hydrogenation, the investigation on the solubility of ccMA dissolution in different polar solvents has been carried out by characterizing and modelling the dissolution as a function of temperature. Water, ethanol, 2-propanol and acetic acid have been investigated as solvents in the range temperatures from a 298.15 to 348.15 K. Owing to the absence of ccMA solubility data, the reliability of the adopted experimental set-up was validated comparing published and experimental solubility data of a similar compound, that is, AA. From the results, it has emerged that the employed system is appropriate for the determination of molar fractions of an organic compound dissolved in polar solvents. The molar fraction and temperature were correlated using the Apelblat equation model, which is applied for the mathematic fitting of experimental data.
A total relative average deviation of 3.54% was obtained for the experimental results and the solubility data obtained with the model, thus attesting the adequacy for this study. The use of Apelblat equation also allowed to determine the apparent molar enthalpy and molar entropy of dissolution. The dissolution of ccMA in water, ethanol, 2-propanol and acetic acid, over temperatures ranging from 298.15 to 348.15 K, has been shown to be endothermic.
The activity of Pt-based catalysts has been compared with a Ni-based catalyst at a gentle condition. A supported 14.2 wt.% Ni on γ-alumina converted 100% of muconic acid, yielding 99.4 mol.% of AA.
Finally, the oxidative cracking of 5-keto-L-aldonic acids to tartaric acid (TarA) was successfully performed at room temperature and atmospheric pressure in a carbonate buffer (pH = 10.34), by employing various V-based catalysts. The performance of the novel heterogeneous V-based catalysts was compared with the one of a conventional homogeneous system.
The effect of the catalysts was obvious and 2%VOx/ZrO2 was found to be the best catalyst for the 5-keto-aldonic acids conversion to tartaric acid. The tartaric acid selectivity was equal to 74.5% and 44.3% starting from the 5-keto-D-gluconic acid (5kGl) and 5-keto-L-galactonic acid (5kGa), respectively. The best performances in terms of tartaric acid selectivity were obtained at the beginning of reaction, and about one fourth of the carbon moles were converted into tartaric acid after 24 h of reaction. The substrate was entirely converted after 24 h indicating that several by-products were also produced during the reaction. So, an overall reaction pathway was supposed and the effect of the vanadium structure to the catalytic activity was hypothesized. Moreover, the reaction mechanism of the 5-keto-aldonic acids conversion to tartaric acid promoted by the anchoring VOx-support bond was described.
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Alonzi, Dominic S. "Cellular Mechanism of Glycosylation Inhibition by Imino Sugars." Thesis, University of Oxford, 2007. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.487138.
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Glycosylation is the most common posttranslational modification of proteins. It is a complex process involving many functional proteins and resulting'in a great diversity of structures. The retention of glucose residues on N-linked oligosaccharides following ER a-glucosidase inhibition by imino sugars such as N-butyl deoxynojirimycin, increases the protein misfolding and the amount of glycoprotein destined for degradation via the endoplasmic reticulum associated degradation (ERAD) pathway. Intracellular peptide N-glycosidases (PNGases) act generating free oligosaccharides (FOS) and the protein is targeted for digestion. Free oligosaccharides were extracted from cells treated with NB-DNJ and subjected to ion-exchange chromatography before fluorescence labelling with 2-AA (anthranilic acid) and lectin-affinity chromatography. Separation of labelled FOS by NP-HPLC provided a rapid and sensitive method for the detection of all FOS species resulting from the degradation of glycoprotein exported from the ER. A. robust, cellular-based assay for ER a-glucosidase activity in the presence of inhibitor was developed that provided meaningful kinetics for a-glucosidase-mediated hydrolysis ofN-linked oligosaccharides as proteins are folded in the ER. Furthermore, the origin of FOS generation was studied, to determine the relative amount of FOS produced as a result of ERAD (protein derived) relative to the amount produced by a possible hydrolytic activity of oligosaccharyltransferase (lipid linked derived). A dual localisation of PNGase activity and non-proteasomal and proteasomal ERAD were demonstrated. Analysis of FOS in endomannosidase negative/non-utilised cells revealed the extent of ER/Golgi recycling of glycoproteins and the role of this enzyme in qua~ity control pathways in cells. Oral administration of NB-DNJ results in the production of glucosylated free oligosaccharide in vivo. Further to cellular based assays these glucosylated free oligosaccharides were detected in murine and human samples. The observed differences in the free oligosaccharides produced in different tissues can be explained according to hypothesises generated from culture cell studies. The effects observed with NB-DNJ, a therapeutic with considerable potential for treating lysosomal storage disorders and reducing viral infectious processes, was dose and time dependent so enabling the pharmokinetics of NB-DNJ to be observed. These studies also elucidated a transrenal method of clearance of glucosylated FOS and demonstrate that glucosylated FOS are excellent non-invasive in vivo biomarkers for a-glucosidase inhibition and protein misfolding in the ER.
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Kérourédan, Erwan. "Concise syntheses of diflouroanalogues of cyclitols and sugars." Thesis, University of Leicester, 2006. http://hdl.handle.net/2381/29980.
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The synthesis of (1 fl*,2f*,3S*,4S',)-5,5-dif luorocyclohexane-1,2,3,4-tetrol was accomplished with an overall yield of 20 % from trifluoroethanol over 8 steps featuring a key dehydrofluorination/metallation followed by trapping of aldehyde (scheme). The route based on a fluorinated building block approach delivered rapidly a small library of difluoroanalogues of carbasugars using readily available and inexpensive starting materials where the use of protecting group chemistry was reduced to its minimum as well as purification. This chemistry is unique as a method for the rapid syntheses of difluorinated molecules of this level of complexity and relevance to saccharides. Upjohn r dehydrofluorination/ R3R4c Donohoe f RCM R'v f R", F retaliation, R1 X OH OH OH Claisen The synthesis in water of a range of trifluoroethanol ethers represents an atom efficient and sustainable solution to the multigram scale syntheses of some trifluoroethyl ethers 3-(2 2',2'-Trifluoroethoxy)prop-1-ene was obtained on a mole scale with 99 % yield. Dehydrofluorination/metallation at low temperature (-100 °C) followed by trapping of aldehyde occurred efficiently with a wide variety of substrates allowing a rapid synthesis of dienols on a comfortable scale (up to 75 mmol). After Claisen rearrangement of the dienols, sodium borohydride was found to be the most diastereoselective as well as practical reducing agents tested for the reduction of the hydroketones. Ring closing metathesis using second generation Grubbs' catalyst afforded rapidly key difluorinated cyclohexenes in high yield and low catalyst loading from free diols such as (1 S*,2S*)-6,6-Difluorocyclohex-3-ene-1,2-diol which was obtained with an overall yield of 44 % from trifluoroethanol over 5 steps. The scope and limitations of Upjohn and Donohoe dihydroxylation procedures were identified for our substrates presenting an extensive variety of substitutions. Dihydroxylation under Upjohn conditions exhibited from average to excellent diastereoselectivity depending of the position and level of substitutions. Donohoe-type dihydroxylations delivered the expected outcome for each substrate in very high diastereoselectivity. Indeed (1S*,2S*,3r*,4S*,6S,,)-5>5-difluoro-2,6-dimethylcyclo hexane-1,2,3,4-tetrol was obtained as a single diastereoisomer with an overall yield of 11 % from trifluoroethanol over 8 steps. Also, the use of these intermediates as candidate for analogues of NDP sugars was investigated for a limited number of our substrates such as (1 S*,4f*>5R*,6S'*)-6- (benzyloxy-difluoro.S-dihydroxycyclohexyl dibenzyl phosphate which was synthesised with an overall yield of 27 % from trifluoroethanol over 8 steps.
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McGowan, Sheila Anne. "Modulation of the immune response by imino sugars." Thesis, University of Strathclyde, 2007. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.501808.
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Imino sugars are carbohydrate-like alkaloids largely characterised over the last ten years that function as glycosidase inhibitors as they mimic the sugar moiety of the natural substrate. They have been reported to have immunomodulatory activity and the purpose of this study was to identify and characterise such activity. The ability of over sixty imino sugars to modify macrophage/dendritic cell cytokine production was analysed. The immunomodulatory activity of two imino sugars MNLP 462a and MNLP 24 with pro-inflammatory activity was studied in depth. They were found to upregulate in vitro macrophage IL-12 production and dendritic cell IL-12 and IL-2 production as well as co-stimulatory molecule expression particularly CD40, but in addition CD80 and CD86 on dendritic cells.
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Kedward, Claire. "Crystallization of sugars in the chocolate crumb process." Thesis, University of Nottingham, 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.324012.
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KeÌroureÌdan, Erwan. "Concise syntheses of difluoroanalogues of cyclitols and sugars." Thesis, University of Leicester, 2006. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.436598.
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Holt, Karen Elizabeth. "Asymmetric synthesis of aza-sugars using aldolase enzymes." Thesis, University of Cambridge, 1993. https://www.repository.cam.ac.uk/handle/1810/272658.
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Denman, Carmen Cecile. "From osmolytes to diabetes : the impact of sugars and sugar alcohols on the cystic fibrosis pathogen, Burkholderia multivorans." Thesis, University of Exeter, 2013. http://hdl.handle.net/10871/9787.
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The incidence of CF related diabetes is on the rise as patient life expectancy continues to improve. Sugars elevated in diabetics include glucose, fructose, and mannose. These sugars, in addition to mannitol (recently approved as an inhaled osmolyte) are the basis for this study, aimed at assessing the impact these clinically relevant sugars have on virulence in Burkholderia multivorans. B. multivorans is a member of the Burkholderia cepacia complex (Bcc), and is the most frequent cause of Bcc infection in CF patients. Using an exopolysaccharide-deficient knockout in macrophage and Galleria mellonella infection models, biofilm formation, and adhesion assays, this study has identified exopolysaccharide-dependent and -independent phenotypes. Sequencing of B. multivorans C1576, a CF outbreak isolate, identified three putative adhesins in clinical isolate C1576 but not present in the sequenced environmental strain ATCC17616. Mannitol promoted adhesion and enhanced expression of these adhesins. This study characterised these adhesins and assessed the distribution within other clinical and environmental isolates of B. multivorans and the Bcc. Additionally, transcriptomic profiling of B. multivorans assessed the sugar response and EPS regulation during growth on clinically relevant sugars. Where possible, links were made between phenotypic studies and transcriptome data. B. multivorans EPS derived from fructose and mannitol was subjected to composition analysis using mass spectrometry, and assessed for biological activity. Still relevant to CF related diabetes, the ability of some members of the Bcc to bind insulin was assessed. Results indicated that a minority of strains bound insulin. Furthermore, by using flow cytometry cell sorting and fluorescence microscopy, results also showed only a small number of cells within a given population that bound insulin. In all, this study has added to the knowledge base of B. multivorans but more work is needed to fully understand virulence strategies exploited by this CF pathogen.
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Chance, Deborah L. "Sulfated sugars in cystic fibrosis mucins and the effects of sugar sulfation on the growth of Pseudomonas aeruginosa /." free to MU campus, to others for purchase, 1997. http://wwwlib.umi.com/cr/mo/fullcit?p9841269.
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Homan, Christopher David. "Phosphorus derivatives of carbohydrates." Thesis, University of Newcastle Upon Tyne, 1990. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.239564.
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Park, Sung-Hae. "The biosynthesis of the deoxyhexose moieties in oleandomycin /." Thesis, Connect to this title online; UW restricted, 1999. http://hdl.handle.net/1773/8152.
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Yuhas, Maryam. "Improving Rural Health Disparities: Understanding and Addressing Intake of Added Sugars and Sugar-Sweetened Beverages among Adults and Adolescents." Diss., Virginia Tech, 2019. http://hdl.handle.net/10919/100730.
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Around 46.2 million Americans living in rural areas are disproportionately burdened by health disparities. Likewise, obesity and obesity-associated diseases (e.g., diabetes, cardiovascular disease) are much higher for rural residents when compared to their urban counterparts. There is a high need to understand and address the nutritional determinants of these health inequities among adults and adolescents. One area of concern in rural dietary habits pertains to added sugars and more specifically, sugar-sweetened beverages (SSB). Excessive added sugars and SSB intake have been strongly linked to many of the nutrition and chronic disease disparities impacting rural residents. Moreover, studies conducted in rural populations have found high consumptions of these in both adults and adolescents. There is an opportunity to better understand added sugars and SSB patterns in rural populations to inform the development of culturally relevant, multi-level interventions that address high consumption. Study #1 is a cross-sectional study that explores top food and beverage sources of added sugars in the diet of adults (n = 301) living in rural areas of Southwest Virginia. Study #2 uses a nationally representative sample of adolescents (n = 1,560) from the Family Life, Activity, Sun, Health and Eating (FLASHE) study sponsored by the National Cancer Institute, to explore factors across the levels of the socioecological model associated with adolescent SSB intake. Study #3 utilizes focus groups and a pilot trial to understand language preferences, acceptability and use of SMS aimed at caregivers to reduce SSB intake in both caregivers and adolescents living in rural areas of Southwest Virginia (n = 33). Collectively, these three studies offer recommendations and culturally relevant strategies for future large-scale trials aimed at reducing SSB intake among adolescents and caregivers in rural communities and ultimately reducing rural health disparities.Doctor of Philosophy
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Bierenstiel, Matthias. "Transition Metal Catalyzed Selective Oxidation of Sugars and Polyols." Diss., lmu, 2005. http://nbn-resolving.de/urn:nbn:de:bvb:19-37863.
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Schneider, L. (Laura). "Mechanocatalytic pretreatment of lignocellulosic barley straw to reducing sugars." Doctoral thesis, Oulun yliopisto, 2017. http://urn.fi/urn:isbn:9789526216478.
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Abstract Biomass conversion methods represent bioeconomic solutions for the sustainable production of value added commodities (chemicals and materials) as well as for energy purposes, either in solid (pellets), liquid (transport fuels) or gaseous (combustion gases e.g. biomethane) form. Lignocellulosic biomass as a renewable source available in immense quantity, is considered to be one of the most promising natural sources, with high potential in the replacement of conventional transportation fuels and reduction of greenhouse gas emissions. This thesis provides new insights into mechanocatalysis, which as yet is a novel technique in catalytic biomass conversion. The mechanocatalytic approach combines chemical catalysis and mechanical assisted processing driven by ball milling. Lignocellulosic barley straw was impregnated or merely mixed with the catalyst (formic acid, acetic acid, sulfuric acid, oxalic acid dihydrate and potassium pyrosulfate) and ball milled under various conditions yielding the selective depolymerization of lignocellulose into water-soluble xylo-oligosaccharides. Subsequent hydrolysis at moderate temperatures resulted in the formation of valuable reducing sugars, mainly xylose, galactose, arabinose and glucose, which constitute the basic materials for transportation fuel and chemical production. Reducing sugar release of 53.4 wt% with low by-product formation was observed within short milling durations using sulfuric acid as a catalyst in mechanocatalysis. Likewise, oxalic acid dihydrate and potassium pyrosulfate as a novel catalyst, successfully converted barley straw to reducing sugars (42.4 wt% and 39.7 wt%, respectively), however longer milling durations were required. In comparison, lower saccharification (<10 wt%) was obtained by employing formic acid and acetic acid in mechanocatalysis. Harsh milling conditions initiated a temperature increase within the reaction vessel resulting in enhanced sugar release. Likewise, greater sugar release was observed with increased catalyst amount and acidity. The results revealed that the balance of these factors is crucial for efficient catalytic conversion of barley strawTiivistelmä Biomassan konvertointimenetelmät mahdollistavat biotalouden hengen mukaisesti uusia ratkaisuja kemikaalien ja materiaalien kestävään tuotantoon sekä biomassan energiakäyttöön eri muodoissa (kuten pelletit, biopolttoaineet ja biokaasu). Lignoselluloosapohjaista, uusiutuvaa biomassaa, kuten tässä työssä tutkittua ohran olkea, on runsaasti saatavilla. Lignoselluloosa onkin yksi lupaavimmista raaka-aineista korvaamaan fossiilisia polttoaineita ja vähentämään kasvihuonekaasupäästöjä. Väitöskirjatutkimus antaa uutta tietoa ohran oljen mekaanis–katalyyttisestä käsittelystä, mikä on suhteellisen uusi menetelmä biomassan katalyyttisessä muokkauksessa. Menetelmässä yhdistetään kemiallinen katalyysi ja mekaaninen muokkaus (jauhatus) kuulamyllyllä. Lignoselluloosa (ohran olki) impregnoitiin tai sekoitettiin tutkitun katalyytin (muurahaishappo, etikkahappo, rikkihappo, oksaalihappodihydraatti, kaliumpyrosulfaatti) kanssa ja käsiteltiin erilaisissa mekaanis–katalyyttisissä olosuhteissa. Lignoselluloosan selektiivinen depolymerointi muodosti vesiliukoisia oligosakkarideja ja edelleen hydrolyysin kautta pelkistyneitä sokereita (pääasiassa ksyloosia, galaktoosia, arabinoosia ja glukoosia), joita voidaan käyttää biopolttoaineiden ja -kemikaalien valmistuksessa. Tutkimuksen tulosten perusteella rikkihappokatalyytillä saatiin 53,4 massa-% ohran oljen sisältämistä pelkistyneistä sokereista vapautettua lyhyillä käsittelyajoilla. Lisäksi sivutuotteiden muodostuminen oli vähäistä. Vastaavasti oksaalihappodihydraatti (sokerisaanto 42,4 massa-%) ja kaliumpyrosulfaatti (sokerisaanto 39,7 massa-%) toimivat uusina katalyytteinä hyvin, mutta vaativat rikkihappokatalyyttiä pidemmät jauhatusajat. Sen sijaan muurahaishapolla ja etikkahapolla sokerisaanto oli erittäin alhainen (alle 10 massa-%) mekaanis–katalyyttisessä käsittelyssä. Tutkimuksessa todettiin, että voimakas jauhatus vaikutti selkeästi reaktiolämpötilan nousuun käsittelyn aikana, mikä edisti korkeampaa sokerisaantoa. Vastaavasti sokerisaantoa voitiin parantaa katalyyttimäärällä ja happamuudella. Tulokset osoittavat, että näiden muuttujien tasapaino on ratkaisevaa ohran oljen tehokkaan katalyyttisen muuntamisen kannalta
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Mellor, Howard R. "The biological properties of novel N-alkylated imino sugars." Thesis, University of Oxford, 2003. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.398134.
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Geary, Peter Michael. "The co-crystallisation of sugars by the supersaturation process." Thesis, University of Hull, 2008. http://hydra.hull.ac.uk/resources/hull:2576.
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Co-crystallising sugars by the supersaturation process was investigated using sucrose and lactose as the matrix sugars. The components to be cocrystallised with either sucrose or lactose were a variety of mono- and disaccharides along with sweeteners such as saccharin. Analysis of the materials yielded from the supersaturation process was done primarily by differential scanning Calorimetry (DSC) and powder x-ray diffraction (PXRD). DSC analysis allowed information to be obtained on the thermal behaviour of the various co-crystalline materials, whilst PXRD permitted information on the structural aspects of the materials to be gained. These two forms of analysis were complimentary to each other, each revealed unique characteristics of the co-crystalline materials. To unambiguously differentiate the difference between a material that is co-crystalline and one that is not, physical blends of the sugars to be cocrystallised were analysed by DSC and PXRD. This approach allowed for identification of all the components in the mixture, more importantly, this identification was achievable at all levels of the second component in the mixture. Co-crystallising either sucrose or lactose, with various sugars, yielded solely co-crystalline material up to a certain level of the added sugar. Once this level has been reached, two distinct phases appear in both DSC and PXRD analysis. A co-crystallised and a phase relating to the added sugar can be observed. The formation of a potentially co-crystalline material appears to result from a direct inclusion of the added sugar into the matrix sugar. DSC analysis of the co-crystallised material revealed thermal behaviour that is suggestive of a doping of the matrix sugar by the added component. PXRD analysis did provide some data to further this argument, axis elongation for co-crystallised material is suggestive of a sopping of the main phase. However, determination of the unit cell volumes did not yield conclusive evidence to help prove this hypothesis though. This behaviour in both forms of analysis was generally proportional to the quantity of the second component that has become included into the matrix sugar. The formation of solely co-crystalline materials appears to rely on the structural similarity between the matrix sugar and the component to be included. A higher degree of similarity is reflected by a high level of inclusion of the added component. Co-crystallisation appears to rely on a degree of intermolecular sugar-sugar recognition. The inclusion of a second component is not solely down to structural similarities between materials however. It appears that there are kinetic factors potentially involved to. Varying the method of co-crystallisation allowed for higher, or lower, amounts of various second components to be included within a matrix sugar. The appearance of co-crystalline materials may be due to the inclusion of the second component in an amorphous state. Analysis by Autosorb of various co-crystalline materials has dispelled this idea. All co-crystalline materials behaved in a manner that was indicative of a crystalline material. During the course of the work with sucrose, it was noted that a unique melting point was observed. From previous work, this unique phase was thought to be a hydrated form of sucrose. Further analysis on this material has allowed for further postulation on its formation and on new methods of its synthesis.
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Liu, Wei-Chun. "Studies of enzymes that process and use charged sugars." Thesis, University of Oxford, 2011. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.547468.
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Neuss, Judi. "Fragmentation-cyclisation approaches to the synthesis of aza-sugars." Thesis, University of Nottingham, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.338541.
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