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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
11

Vers la synthèse totale du FR225654 inhibiteur de la gluconéogenèse / Total synthesis of FR225654

Mohammad, Shabbair 03 December 2013 (has links)
Le diabète de type 2 est aujourd’hui une maladie de plus en plus répandu. En ce sens il est nécessaire de mettre au point de nouveau composé permettant d’inhiber la gluconéogenèse. C’est pourquoi nous nous sommes intéressé à la synthèse du FR225654 1, décaline présentant une activité hypoglycémiante in vivo après administration par voie orale et inhibiteur de la néoglucogenèse in vitro (IC50 = 1,1.10-7 M). Ce composé, isolé en 2005 du champignon Phoma sp N°00144 et jamais encore synthétisé à ce jour, possède un mécanisme d’action inconnu. La nécessité d’une synthèse par voie chimique convergente et flexible, permettant l’accès à des analogues, est donc évidente. La stratégie consistait à préparer une trans-décaline par le biais d’une réaction de Diels-Alder intramoléculaire à partir d’un triène précurseur. La combinaison de ces travaux a constitué une avancée importante dans le cadre de la synthèse du FR225654, un hypoglycémiant potentiel. La mise au point d’une synthèse convergente du précurseur de la réaction de Diels-Alder permettra notamment d’effectuer par la suite des modifications aisées en vue de la préparation d’une vaste gamme d’analogues simplifiés. A ce jour, le produit de cyclo-addition a été isolé et caractérisé, validant ainsi l’étape clé de la stratégie de synthèse. Ainsi, l’accès rapide au FR225654 est rendu possible et la synthèse d’analogues est maintenant envisageable. Les produits synthétisés feront l’objet d’une évaluation biologique, l’objectif ultime étant d’accéder à de nouveaux médicaments pour le traitement du diabète de type 2. / Type 2 diabetes mellitus (T2DM) is a growing worldwide health concern that is expected to afflict over 366 million people by 2030. FR225654 is a novel gluconeogenesis (GNG) inhibitor recently isolated from the culture broth of Phoma sp.. This compound selectively inhibits GNG of primary rat hepatocytes and shows highly hypoglycemic effects in several in vivo mouse models (80% decrease of glycemia). However, to date, the mechanism of action and molecular target remain unknown. From a structural point of view, FR225654 exhibits a highly oxygenated trans-decalin ring substituted by a β-keto-enol moiety and a side-chain bearing a conjugated carboxylic acid and a trisubstituted olefin. Project specific objectives were to design an efficient total synthesis which could also permit a straightforward access to diverse analogues. This feature would constitute a crucial step for the further understanding of Structure Activity Relationship of FR225654. The work consists in synthesizing separately a side chain and a trans-decalin core by means of an intramolecular Diels-Alder reaction from a precursor. To date, synthesis of the precursor has been achieved in 13 steps as well as the side chain. The Intramolecular Diels-Alder reaction has also been validated in order to accomplish the first total synthesis of FR225654.
12

Synthesis of Novel Polyhydroxyl Surfactants. Influence of the Relative Stereochemistry on Surfactant Properties.

Neimert-Andersson, Kristina January 2003 (has links)
<p>This thesis deals with the synthesis and characterization ofnovel polyhydroxyl surfactants. The first part describes thesynthesis of a number of stereoisomers of a polyhydroxylsurfactant, and the second part concerns surface chemicalcharacterization.</p><p>A stereodivergent route for preparation of the hydrophilichead group was developed, featuring consecutive stereoselectivedihydroxylations of a diene. This afforded in total fourdifferent polyhydroxyl head groups. These surfactant headgroups were natural and unnatural sugar analogues, and wereused for the coupling with two different hydrophobic tailgroups.</p><p>Three of these surfactants were used to investigate thechiral discrimination in Langmuir monolayers at an air-waterinterface. The isotherms showed a remarkable difference incompressibility between surfactants of diastereomericrelationship and also a pronounced chiral discriminationbetween racemic and enantiomerically pure surfactants favoringheterochiral discrimination.</p>
13

Synthesis of Polyhydroxylated Surfactants : Comparison of Surfactant Stereoisomers and Investigation of Haemolytic Activity

Neimert-Andersson, Kristina January 2005 (has links)
I den här avhandlingen har vi studerat hur man kan göra nya tensider. En tensid är en speciell molekyl som har förmågan att lösa sig i både vatten och olja. Man kan göra följande experiment hemma: Fyll en glasburk till hälften med vatten och tillsätt en droppe matolja. Oljan bildar en droppe ovanpå vattnet, därför att vatten och olja inte är blandbara. Vatten är polärt och olja är opolärt. Om man rör om med en sked kommer oljedroppen förvisso att dela upp sig i mindre droppar, men så snart man slutar att röra kommer dessa att lägga sig på vattenytan igen. Sätt nu en droppe diskmedel till blandningen och rör om. Nu sprider sig oljedropparna mycket bättre i vattnet, och de lägger sig heller inte på vattenytan lika fort när man slutar att röra. Det här beror på att diskmedel innehåller en tensid, som har en polär och en opolär del. Den polära delen passar ihop med det polära vattnet, medan den opolära delen passar ihop med den opolära oljan. På så vis kan tensiden hjälpa till att lösa upp opolära ämnen i polära vätskor. Den aktiva delen av ett läkemedel består ofta av opolära ämnen, vilka inte löser sig i polära vätskor såsom vatten. Eftersom kroppen består till stor del av vatten måste man ändå försöka få läkemedlet vattenlösligt, för att möjliggöra transport via blodet till problemområdet. Det kan man uppnå genom att tillsätta tensider. Om läkemedel-tensidblandningen ska ges till djur eller människor får inte tensiden orsaka någon skada i kroppen. Vi har försökt framställa tensider som ska kunna användas för att just lösa läkemedel i vatten. För att kunna framställa nya tensider måste man ha kunskap i organisk syntes. Det betyder att man måste veta hur man från små intermediat (”byggstenar”) successivt kan bygga upp nya molekyler som har de önskvärda egenskaperna. Genom olika typer av organisk syntes har vi byggt upp tre nya tensidtyper, vars egenskaper vi studerat med olika mätningar. Ingen av dessa tensider lämpade sig som tillsats till läkemedel, men vårt arbete har givit mycket ny kunskap om hur framtida tensidmolkyler kan tillverkas och vilka egenskaper de får. / This thesis deals with the synthesis and characterization of new polyhydroxy surfactants. The first part describes the synthesis of three new surfactant classes, and the second part concerns the surface chemical characterization of the synthesized surfactants. A stereodivergent route for preparation of hydrophilic head groups was developed, that featured consecutive stereoselective dihydroxylations of a diene. This method provided in total four different polyhydroxylated head groups. These surfactant head groups were natural and unnatural sugar analogues, and were used for the coupling with two different hydrophobic tail groups. Another approach took advantage of a metathesis reaction and provided a polyhydroxylated compound that was coupled to 12-hydroxy stearic acid The third class of surfactants contained an amide linkage between the hydrophilic and the hydrophobic parts. The hydrophilic part consisted of two glucose units, and 12-hydroxy stearic acid was used as the hydrophobic part. The hydroxy moiety in the tail group was further functionalized as aliphatic esters, which provided in total four different surfactants. A selection of the surfactants was used to investigate the chiral discrimination in Langmuir monolayers at an air-water interface. The isotherms showed a remarkable difference in compressibility between diastereomeric surfactants and also a pronounced chiral discrimination between racemic and enantiomerically pure surfactants, favoring heterochiral discrimination. The monolayers were also investigated with Brewster angle microscopy (BAM) and grazing incidence X-ray diffraction (GIXD). It was not possible to observe any chirality dependent features from the BAM images, but the GIXD measurement supported the conclusion that heterochiral discrimination governed the intermolecular forces within the racemic monolayer. The third class of surfactants, containing an amide linkage between the glucose units and 12-hydroxy stearic acid was evaluated with respect to the CMC and the haemolytic activity. These surfactants were all haemolytic close to their respective CMC. / QC 20101015
14

Stereoselective Synthesis Of Optically Active Cyclitol Precursors Via Chemoenzymatic Method And Synthesis Of A Nucleoside Precursor

Oguzkaya, Funda 01 June 2006 (has links) (PDF)
ABSTRACT STEREOSELECTIVE SYNTHESIS OF OPTICALLY ACTIVE CYCLITOL PRECURSORS VIA CHEMOENZYMATIC METHOD AND SYNTHESIS OF A NUCLEOSIDE PRECURSOR Oguzkaya, Funda M.S., Department of Chemistry Supervisor: Prof. Dr. Cihangir Tanyeli June 2006, 99 pages &amp / #945 / &#039 / -acetoxylation of &amp / #945 / ,&szlig / -unsaturated cyclic ketones was adjusted via Mn(OAc)3 in regioselective manner. Then, PLE hydrolysis was carried out so as to afford enantiomerically enriched &amp / #945 / &#039 / -acetoxylated and &amp / #945 / &#039 / -hydroxylated cyclic compounds. From our knowledge about the literature and previous works dealing with &amp / #945 / &#039 / -hydroxylated products which are easily racemized, protection was directly adjusted via acetylation so as to prevent this possibility. Resulting enantiomerically enriched products were subjected to Upjohn Dihydroxylation to obtain cyclitol precursors and following Luche Reduction of ketone was adjusted so as to obtain corresponding cyclitols. In addition with such synthetic design, firstly dimethyl cyclopent-3-ene-1,1-dicarboxylate was obtained so as to reach in former manner 3-cyclopentene-1,1-dicarboxylic acid, and in latter manner cyclopent-3-enecarboxylic acid. Resulting compound was converted to 6-iodo-2-oxa-bicyclo[2.2.1]heptan-3-one and followingly to the target nucleoside precursor which is 2-oxa-bicyclo[2.2.1]hept-5-en-3-one.
15

Synthesis of Polyhydroxylated Surfactants : Comparison of Surfactant Stereoisomers and Investigation of Haemolytic Activity

Neimert-Andersson, Kristina January 2005 (has links)
<p>I den här avhandlingen har vi studerat hur man kan göra nya tensider. En tensid är en speciell molekyl som har förmågan att lösa sig i både vatten och olja.</p><p>Man kan göra följande experiment hemma: Fyll en glasburk till hälften med vatten och tillsätt en droppe matolja. Oljan bildar en droppe ovanpå vattnet, därför att vatten och olja inte är blandbara. Vatten är polärt och olja är opolärt. Om man rör om med en sked kommer oljedroppen förvisso att dela upp sig i mindre droppar, men så snart man slutar att röra kommer dessa att lägga sig på vattenytan igen. Sätt nu en droppe diskmedel till blandningen och rör om. Nu sprider sig oljedropparna mycket bättre i vattnet, och de lägger sig heller inte på vattenytan lika fort när man slutar att röra. Det här beror på att diskmedel innehåller en tensid, som har en polär och en opolär del. Den polära delen passar ihop med det polära vattnet, medan den opolära delen passar ihop med den opolära oljan. På så vis kan tensiden hjälpa till att lösa upp opolära ämnen i polära vätskor.</p><p>Den aktiva delen av ett läkemedel består ofta av opolära ämnen, vilka inte löser sig i polära vätskor såsom vatten. Eftersom kroppen består till stor del av vatten måste man ändå försöka få läkemedlet vattenlösligt, för att möjliggöra transport via blodet till problemområdet. Det kan man uppnå genom att tillsätta tensider. Om läkemedel-tensidblandningen ska ges till djur eller människor får inte tensiden orsaka någon skada i kroppen.</p><p>Vi har försökt framställa tensider som ska kunna användas för att just lösa läkemedel i vatten. För att kunna framställa nya tensider måste man ha kunskap i organisk syntes. Det betyder att man måste veta hur man från små intermediat (”byggstenar”) successivt kan bygga upp nya molekyler som har de önskvärda egenskaperna. Genom olika typer av organisk syntes har vi byggt upp tre nya tensidtyper, vars egenskaper vi studerat med olika mätningar. Ingen av dessa tensider lämpade sig som tillsats till läkemedel, men vårt arbete har givit mycket ny kunskap om hur framtida tensidmolkyler kan tillverkas och vilka egenskaper de får.</p> / <p>This thesis deals with the synthesis and characterization of new polyhydroxy surfactants. The first part describes the synthesis of three new surfactant classes, and the second part concerns the surface chemical characterization of the synthesized surfactants.</p><p>A stereodivergent route for preparation of hydrophilic head groups was developed, that featured consecutive stereoselective dihydroxylations of a diene. This method provided in total four different polyhydroxylated head groups. These surfactant head groups were natural and unnatural sugar analogues, and were used for the coupling with two different hydrophobic tail groups.</p><p>Another approach took advantage of a metathesis reaction and provided a polyhydroxylated compound that was coupled to 12-hydroxy stearic acid</p><p>The third class of surfactants contained an amide linkage between the hydrophilic and the hydrophobic parts. The hydrophilic part consisted of two glucose units, and 12-hydroxy stearic acid was used as the hydrophobic part. The hydroxy moiety in the tail group was further functionalized as aliphatic esters, which provided in total four different surfactants.</p><p>A selection of the surfactants was used to investigate the chiral discrimination in Langmuir monolayers at an air-water interface. The isotherms showed a remarkable difference in compressibility between diastereomeric surfactants and also a pronounced chiral discrimination between racemic and enantiomerically pure surfactants, favoring heterochiral discrimination. The monolayers were also investigated with Brewster angle microscopy (BAM) and grazing incidence X-ray diffraction (GIXD). It was not possible to observe any chirality dependent features from the BAM images, but the GIXD measurement supported the conclusion that heterochiral discrimination governed the intermolecular forces within the racemic monolayer.</p><p>The third class of surfactants, containing an amide linkage between the glucose units and 12-hydroxy stearic acid was evaluated with respect to the CMC and the haemolytic activity. These surfactants were all haemolytic close to their respective CMC.</p>
16

Synthesis of Novel Polyhydroxyl Surfactants. Influence of the Relative Stereochemistry on Surfactant Properties.

Neimert-Andersson, Kristina January 2003 (has links)
This thesis deals with the synthesis and characterization ofnovel polyhydroxyl surfactants. The first part describes thesynthesis of a number of stereoisomers of a polyhydroxylsurfactant, and the second part concerns surface chemicalcharacterization. A stereodivergent route for preparation of the hydrophilichead group was developed, featuring consecutive stereoselectivedihydroxylations of a diene. This afforded in total fourdifferent polyhydroxyl head groups. These surfactant headgroups were natural and unnatural sugar analogues, and wereused for the coupling with two different hydrophobic tailgroups. Three of these surfactants were used to investigate thechiral discrimination in Langmuir monolayers at an air-waterinterface. The isotherms showed a remarkable difference incompressibility between surfactants of diastereomericrelationship and also a pronounced chiral discriminationbetween racemic and enantiomerically pure surfactants favoringheterochiral discrimination. / <p>NR 20140805</p>
17

Asymmetric Dihydroxylation and Aziridination of Allenes and Related Chemistry

Liu, Renmao 11 May 2007 (has links) (PDF)
A novel method for asymmetric synthesis of α-hydroxy ketone with excellent regio- and stereoselectivity has been established by the systematic investigation of asymmetric dihydroxylation of allenes. The efficiency of kinetic resolution of racemic allenes was also investigated by using the AD reaction on both 1,3-disubstituted and trisubstituted allenes. Steric effects, electronic effects and allene substitution are also discussed. Aziridines were formed by copper-catalyzed intramolecular nitrene addition to alkenes. The carbamate group was used as the tether between the alkene and the nitrene. Subsequent nucleophilic attack of the aziridine was accomplished using RSH, R2NH, N3-,or ROH as the nucleophile. This addition was found to be regio- and stereoselective. This methodology has provided a new strategy for the stereoselective construction of three adjacent functional groups, in particular the 1,2 diamino-3-hydroxy unit. The rhodium-catalyzed intramolecular aziridination of allenic N-sulfonyloxy carbamates has been established. Efficient ring opening of these bicyclic compounds may provide synthetic utility in organic chemistry. The intramolecular aziridination of allenic sulfamate esters was tested on a single example to afford in situ a ring opened product.
18

Vers la synthèse totale de la Thapsigargine inhibiteur de l’enzyme SERCA / Toward the total synthesis of thapsigargin, an inhibitor of SERCA enzyme

Tap, Aurélien 16 December 2013 (has links)
La thapsigargine (Tg) est une lactone sesquiterpène polyoxygénée appartenant à la famille des guaianolides, isolée de Thapsia (Apiacae), une plante poussant communément dans le basin méditerranéen. Son intérêt dans le traitement du cancer de la prostate est basé sur son potentiel inhibiteur de l’enzyme endo/sarcoplasmique calcium ATPase (SERCA). Ce phénomène conduit à une augmentation de la concentration du calcium dans le lumen du réticulum endoplasmique et engendre une apoptose cellulaire. Dans un premier temps, un modèle 8-desoxy-bicyclo[5.3.0]decadiénone, de structure proche du squelette de la Tg, a été synthétisé par le biais d’une réaction clé de Pauson-Khand allène-yne catalysée par un complexe de rhodium. L’approche directe développée est robuste avec de hautes sélectivités et rendements. Cette voie a ensuite été appliquée à la synthèse du produit naturel. A partir d’un époxyde optiquement enrichi, la partie Sud de la Tg (le motif lactonique) est tout d’abord mise en place. Les centres C6 et C8 sont ensuite construits respectivement par alcynylation/réduction asymétrique et par propargylation énantiosélective. Cette première approche a permis d’isoler un produit énantiopure possédant les centres chiraux C6, C7 et C8 ainsi que du motif lactonique en dix-sept étapes. Une seconde voie a été initiée permettant la mise en place plus rapide de la partie Sud de la molécule incluant les centres asymétriques C6, C7, C8 et C11 par le biais d’une réaction de dihydroxylation. Cette seconde voie a permis d’isoler un produit racémique possédant les centres chiraux C6, C7, C8 et C11 ainsi que du motif lactonique en dix étapes. Parallèlement, une étude méthodologique a été menée sur la réaction de Pauson-Khand allénol-yne intramoléculaire. Treize composés bicycliques ont été synthétisés en série acétal et NTs. / Thapsigargin (Tg) is a highly oxygenated sesquiterpene lactone belonging to the guaianolide family, isolated from the Mediterranean plant species Thapsia (Apiaceae). Its interest towards treatment of prostate cancer is based on the potency of this compound as an inhibitor of the endo/sarcoplasmic calcium ATPase (SERCA) inducing an increase in cytosolic calcium concentration and leading to apoptotic cell death. A straightforward approach to a highly functionalized 8-desoxy-bicyclo[5.3.0]decadienone model close to the Tg framework has been achieved through a key Rh(I) allenic Pauson-Khand reaction (APKR). The synthetic route developed therein is robust and the yields and selectivities are high. This approach was used in the synthesis of the natural compound. Starting from the same chiral epoxide, the bottom portion of the Tg (lactone core) is first built, then C6 and C8 carbons are functionalized respectively by asymmetric reduction and enantioselective propargylation. This first way allowed to synthesize a seventeen steps-enantiopure product with C6, C7, C8 chiral centers and the lactone core. A second way is performed to set up faster the bottom part of the molecule included C6, C7, C8 and C11 asymmetric centers through a dihydroxylation step. This second approach allowed to synthesize a ten steps-racemic product with C6, C7, C8, C11 chiral centers and the lactone core. Meanwhile, a methodological study was conducted on the intramolecular allenol-yne Pauson-Khand reaction. Thirteen bicyclic compounds were synthesized in acetal and NTs series.
19

PREPARATION AND EVALUATION OF DECONSTRUCTION ANALOGS OF 7-DEOXYKALAFUNGIN AS AKT INHIBITORS

Korwar, Sudha 27 July 2012 (has links)
Pyranonaphthoquinone lactones have been recently found to be selective inhibitors of the serine-threonine kinase AKT/PKB. AKT/PKB plays a major role in tumorigenesis, hence these compounds have a great potential to act as anti-cancer agents. They act by a novel bioreductive alkylation mechanism of inhibition of AKT/PKB. In this work, 7-deoxykalafungin, a pyranonaphthoquinone lactone and its deconstruction analogs were synthesized. The structural features of the compounds necessary to inhibit AKT1 potently and selectively were determined. It was observed that compounds with a pyran ring were more potent in inhibiting AKT1. Conversely, flexible compounds were found to be weak inhibitors of AKT1. Also, presence of a lactone ring was found to be favorable in inhibiting AKT1. Of the compounds tested, 7-deoxykalafungin was the most potent inhibitor of AKT1 (IC50 = 0.28 µM against AKT1) and compound 4-61 was the most potent inhibitor of PKA (IC50 = 0.43 µM against PKA).
20

Untersuchungen zur enantioselektiven Totalsynthese von Parnafungin C / Studies towards the Enantioselective Total Synthesis of Parnafungin C

Heidemann, Sven 04 August 2016 (has links)
No description available.

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