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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.
1

THE SYNTHESIS, STRUCTURE, AND REACTIVITY OF SOME ORGANOMETALLIC-FUSED HETEROCYCLES

Tice, Nathan Charles 01 January 2006 (has links)
The synthesis, structure, and reactivity of some organometallic-fusedheterocycles were studied. This work was divided into three parts: first,thiapentalenyl tricarbonyl manganese complexes [Mn(CO)3{??5-SC7H3-1,3-(R)2}]were synthesized employing thiation on diacyl precursors; second, attempts toform the 5,5-fused ring pyrrole analogs to the thiapentalenyl complexes led to theformation of various amine and imine ligands and manganese complexes, but notthe desired ring-closed pyrroles; third, reductive amination on a ferrocenylmonoaldehyde substrate led to the formation of di(N-(ferrocenylmethyl))-Nmethylamineand its cyanoborane and cyanoborohydride analogs.Isolation of the desired thiapentalenyl manganese complexes wasaccomplished by first forming 1,2-diacylcyclopentadienes (fulvenes), convertingto the corresponding thallium salts [Tl{1,2-C5H3(COR)2}] employing thalliumethoxide, transmetallating with [Mn(CO)5Br], and ring closing using either P4S10or Lawesson's Reagent. Ring closure from the diacylmanganese complexes[Mn(CO)3{??5-1,2-C5H3(COR)2}] gave air stable thiapentalenyl complexes inmoderate to good yield and was tolerable to a variety of functional groups (aryl,arylacetyl, t-butyl). In the cases where 1,2-diarylacetyl complexes wereemployed, the isolated products were "quinoidal". While ring closure on thecorresponding diacylrhenium tricarbonyl complexes was not feasible, it wasobserved that these quinoidal thiapentalenyl structures could be formed on aruthenium Cp* moiety using the arylacetyl fulvenes.Various keto-amines or enol-imines could be formed from the 1,2-dibenzoyl fulvene employing primary amines (R = H, Me, OH, OMe). In thepresence of a reducing agent, neither reduction nor ring closure was observedfor any of the cases investigated. Formation of the corresponding manganesetricarbonyl complex for the methyoxyimine case was accomplished by reaction ofthe enol-methoxyimine with thallium ethoxide and then transmetallating with[Mn(CO)5Br]. Reaction of this keto-imine complex with various reducing agentsdid not lead to the desired 5,5-fused ring pyrrole complex but to reduction to thecorresponding alcohol.Diferrocenylmethyl methylamine complexes were obtained by reaction offerrocene monoaldehyde with ferrocenylmethyl methylamine in the presence of amild reducing agent (NaCNBH3). Isolation under anhydrous conditions gave theunexpected cyanoborohydride salt, di(N-(ferrocenylmethyl))-N-methylammoniumcyanoborohydride. Aqueous work-up gave the corresponding free amine.Conversion of the cyanoborohydride salt to the corresponding cyanoborane,di(N-(ferrocenylmethyl))-N-methylammonium–cyanoborane, was accomplishedby refluxing the cyanoborohydride salt in THF.
2

Amine Transaminases in Biocatalytic Amine Synthesis

Land, Henrik January 2016 (has links)
The use of enzymes, nature´s own catalysts, both isolated or as whole cells to perform chemical transformations is called biocatalysis. As a complement to classical chemical catalysis, biocatalysis can be an environmentally friendly and more economical option in the production and synthesis of chemicals. Research on the application of amine transaminases in synthesis of chiral amines have exploded over the last two decades and interest from the industry is increasing. Amine transaminases are promising catalysts due to their ability to perform reductive amination of ketones with excellent enantioselectivity. For a process to be efficient, high substrate specificity of the applied enzyme is an important factor. A variant of Chromobacterium violaceum amine transaminase that was obtained through rational design has an increased specific activity toward (S)-1-phenylethylamine and a set of 4´-substituted acetophenones. This result makes this variant a promising catalyst for the asymmetric synthesis of similar amines. Amine transaminase catalyzed asymmetric synthesis of amines generally suffers from unfavorable equilibrium. Two methods that include spontaneous tautomerization and biocatalytic amidation for equilibrium displacement have therefore been developed. Efficient assays and screening methods are demanded for the discovery and development of novel amine transaminases. For this purpose, a sensitive fluorescence-based assay that holds promise as a high-throughput screening method was developed. One of the major obstacles for application of enzymes in industrial processes is the instability of the enzyme toward harsh conditions. The stability of Chromobacterium violaceum amine transaminase was investigated and improved using co-solvents and other additives. Co-lyophilization with surfactants was also applied to improve the performance of the same enzyme in organic solvents. / <p>QC 20161017</p>
3

Design, synthesis, and biological evaluation of selective sphingosine kinase inhibitors

Raje, Mithun 08 June 2012 (has links)
Sphingosine kinase (SphK) has emerged as an attractive target for cancer therapeutics due to its role in cell proliferation. SphK phosphorylates sphingosine to form sphingosine-1-phosphate (S1P) which has been implicated as a major player in cancer growth and survival. SphK exists as two different isoforms, namely SphK1 and SphK2, which play different roles inside the cell. The dearth of isoenzyme-selective inhibitors has been a stumbling block for probing the exact roles of these two isoforms in disease progression. This report documents our efforts in developing SphK2-selective inhibitors. We provide the first demonstration of a SphK inhibitor containing a quaternary ammonium salt. We developed highly potent and moderately selective inhibitors that were cell permeable and interfered with S1P signaling inside the cell. In an effort to improve the selectivity of our inhibitors and enhance their in vivo stability, we designed and synthesized second generation inhibitors containing a heteroaromatic linker and a guanidine headgroup. These inhibitors were more potent and selective towards SphK2 and affected S1P signaling in cell cultures and various animal models. / Ph. D.
4

Copolymères à base de polycaprolactones greffées par des chitooligosaccharides : vers des nanogels bioactifs et biostimulables / Chitooligosaccharide grafted polycaprolactone copolymers : toward bioactive and biocompatible nanogels : toward bioactive and biocompatible nanogels

Guerry, Alexandre 30 November 2012 (has links)
Actuellement, la mise au point de systèmes de vectorisation d'agents chimio-thérapeutiques performants fait l'objet d'une intense recherche. Les nanoparticules en particulier sont étudiées, car elles permettent de solubiliser des molécules hydrophobes en milieux aqueux tout en diminuant leur toxicité et leur dégradation. Toutefois, le devenir à long terme des nanoparticules est un paramètre important qu'il faut considérer dans la conception de ces nanovecteurs. Pour cette raison, le développement de nanoparticules auto-assemblées constituées de copolymères à bloc entièrement biocompatibles, biodégradables et aux propriétés de libération contrôlée est recommandé. Dans cette perspective, nous avons étudié les propriétés d'auto-organisation de copolymères greffés amphiphiles de type chitooligosaccharide-grafted-polycaprolactone. Le premier chapitre révèle l'utilisation de l'aniline et de son dérivé alcyne comme un outil efficace pour l'amination réductrice de chitooligosaccharides. Dans le second chapitre, différentes familles de polycaprolactone avec des fonctions azide latérales sont décrites. Le troisième chapitre traite du couplage par chimie « click » de chaque bloc ainsi que de la caractérisation physico-chimique des nanoparticules en solution aqueuse. La réticulation de ses particules a permis d'obtenir les nanogels finaux. Pour conclure, des tests d'encapsulation et de libération contrôlée de la Doxorubicine (avec ou sans ajout de glutathion) ont été effectués / Currently, the development of efficient drug delivery systems has a great attention. Nanoparticles are particularly studied for their capacity to solubilise hydrophobic drugs in aqueous media and to decrease their toxicity and degradability. However, long term compatibility has to be considered in the conception of this nanocarrier. For this reasons, the development of self-assembled particles constituted of biocompatible, biodegradable block copolymers is highly recommended. In this perspective, we have studied the self-assembled properties of chitooligosaccharide-grafted-polycaprolactone copolymers. The first chapter reveals aniline catalysis and its alkyne derivative as an efficient way for reductive amination of chitooligosaccharides. The second chapter describes the synthesis of different polycaprolactones with pendant azide groups. The third chapter is dedicated to the grafting of each bloc performed by “click” chemistry as well as the formation and characterisation of nanoparticle conducted in aqueous media. These nanoparticles were cross-linked to form reduction-sensitive final nanogels. At last, entrapment and controlled Doxorubicine release (with or without glutathione) were explored.
5

Synthèses de structurants organiques originaux pour la préparation de nouvelles structures zéolithiques / Synthesis of new zeolites directed by original organic structure directing agents

Bellet, Brice 25 November 2016 (has links)
L’obtention de nouvelles structures zéolithiques a été permise grâce à la diversification des conditions de synthèse, comme l’utilisation d’ions fluorures, la substitution partielle du silicium par du germanium ou l’ajout d’un agent structurant organique. Les travaux développés au cours de cette thèse se concentrent sur la synthèse de nouveaux solides microporeux zéolithiques possédants de larges à extra-larges pores (>10 unités TO4) à l’aide de nouvelles molécules organiques structurantes. Le travail de thèse se divise donc en deux étapes avec, dans un premier temps, la synthèse de molécules organiques originales (dérivées de la pyrrolidine) qui sont ensuite engagées en synthèse hydrothermale. Huit nouveaux structurants non commerciaux ont été élaborés qui ont permis d'obtenir divers matériaux déjà connus, parmi lesquels les zéolithes octadécasil (AST), ITQ-7 (ISV), ITQ-17 (BEC) et ITQ-21. L'utilisation des cations N,N-diméthylperhydro-dicyclopenta[b,d]pyrrolium et N,N-diméthyldicyclopentylammon-ium, ont permis la découverte de deux nouveaux silicogermanates dont l’un de topologie connue nommé clovérite (-CLO) et l’autre nommé Mu-43 présentant une topologie de charpente inédite. Chacun de ces deux matériaux possède un système tridimensionnel de canaux avec des ouvertures à 12 atomes T (Mu-43) ou à 20 atomes T (clovérite). / Several synthetic strategies have emerged such as the use of fluoride, the introduction of germanium and the development of new organic structure directing agents (SDAs) to obtain zeolites, which have led to significant structural diversity. Previous works at the laboratory enable us to develop a new range of non-commercial SDAs that have been designed to produce novel extra-large pores zeolites (>10 TO4 units). Elaborated organic structure directing agents (pyrrolidine derivatives) were first synthesized by a concise route and then engaged in hydrothermal synthesis. Eight non-commercial and original SDAs were produced which led to the synthesis of several known zeolites such as octadecasil (AST), ITQ-7 (ISV), ITQ-17 (BEC) and ITQ-21. The use of the cations N,N-dimethylperhydro-dicyclopenta[b,d]pyrrolium and N,N-dimethyldicyclopentyl-ammonium, allowed us to discover two new silicogermanates named cloverite of known topology -CLO and the novel one Mu 43. Each of these two materials possesses a three-dimensional channel system with 12-membered ring pores (Mu-43) or 20-membered ring pores (cloverite).
6

Développement de nouveaux systèmes réducteurs utilisant des hypophosphites ou des hydrures de calcium : application à la réduction de cétones ainsi qu’aux réactions d’amination et d’alkylation réductrice / Development of new reducing system using hypophosphites or calcium hydride : application to the reduction of ketones and to the reaction of reductive amination and alkylation

Guyon, Carole 03 October 2014 (has links)
Les hydrures de bore et d'aluminium sont très utilisés en chimie organique permettant des réductions hautement chimiosélectives de substrats polyfonctionnels complexes. Les systèmes réducteurs développés jusqu'à nos jours restent incapables d'égaler certaines de ces chimiosélectivités à des coûts compétitifs. L'utilisation des hydrures de bore et d'aluminium pose des problèmes de sécurité, d'environnement et de santé. Leurs réactions génèrent une quantité importante de déchets potentiellement toxiques. Le développement d'alternatives aux hydrures de bore et d'aluminium est donc un enjeu environnemental et économique. Les travaux de cette thèse répondent à cette demande en étudiant l'emploi de dérivés d'hypophosphite et d'hydrure de calcium et de magnésium pour la réduction de fonctions organiques. Ces donneurs d'hydrogènes sont stables à l'air, faciles à manipuler, peu réactifs, peu onéreux et sont composés d'éléments abondants et non toxiques. La réduction de cétones en alcools par l'hypophosphite de sodium a été développée en milieu biphasique en présence de palladium sur charbon ou de complexes de ruthénium homogènes. La réaction avec le palladium sur charbon conduit à un mélange d'alcool et d'alcane. L'optimisation des conditions réactionnelles a permis l'obtention sélective de l'alcool. Une réduction énantiosélective a été développée utilisant RuCl(pcymène)- Ts-DPEN comme catalyseur. Les hydrures de magnésium et de calcium commerciaux ont été activés par broyage mécanique et testés en réduction de l'acétophénone. L'hydrure de calcium a été appliqué à la réaction d'amination et d'alkylation réductrice en présence d'un catalyseur de platine ou de palladium supporté / Boron and aluminum hydrides are widely used in organic chemistry allowing the highly chemoselective reduction of complex multifunctional substrates. Other reducing systems developed until now are unable to equal some of these chemoselectivities with competitive costs. The use of boron and aluminum hydrides raises safety, environmental and health concerns. These reactions produce an important quantity of waste which is potentially toxic. The development of alternatives to boron and aluminum hydrides is thus an environmental and economical issue. This PhD work meets these demands by studying the use of hypophosphite derivatives, calcium and magnesium hydride in the reduction of organic functions. These hydrogen donors are stable to air, easy to handle, poorly reactive, inexpensive and are composed of abundant and non-toxic elements. The reduction of ketones to alcohols by sodium hypophosphite was developed in biphasic media in the presence of palladium on carbon or homogeneous ruthenium complexes. The reaction with palladium on carbon led to a mixture of alcohol and alkane. After optimization of the reaction conditions, alcohols were formed selectively. An enantioselective reduction was developed as well using RuCl(p-cymene)-Ts-DPEN as catalyst. Commercial magnesium and calcium hydride have been activated by ball milling and have been tested in the reduction of acetophenone. Calcium hydride has been applied to the reductive amination and alkylation in the presence of catalytic amount of supported platinum or palladium
7

Reduction of Organic Functional Groups Using Hypophosphites / Réduction des groupes fonctionnels organiques à l'aide d'hypophosphite

Mouselmani, Rim 07 November 2018 (has links)
Récemment, les exigences en chimie ont évolué rapidement, car le développement durable a retenu plus d'attention. Les principes de la chimie verte ont encouragé les chimistes à développer des produits chimiques et des procédés qui réduisent ou éliminent les substances dangereuses. Les travaux de recherche décrits dans cette thèse portent sur le développement de nouveaux systèmes réducteurs en utilisant des hypophosphites comme substituts aux agents réducteurs toxiques traditionnels.Pour atteindre cet objectif, les nitriles aromatiques ont été réduits en aldéhydes correspondants par la formation du gaz de l’hydrogène et de nanoparticules de nickel en combinant un précurseur de nickel avec de l'hypophosphite de calcium en présence d'une base dans un milieu biphasique. De plus, les nitriles aromatiques ont été réduits en amines primaires en utilisant de l'hypophosphite de calcium et le catalyseur hétérogène palladium sur le carbone. La nature du catalyseur métallique, les additifs, les solvants, la température et les concentrations ont été étudiés en détail.D'autre part, l'amination réductrice directe des cétones aliphatiques et aromatiques a été réalisée pour la première fois en utilisant du palladium hétérogène sur du carbone et de l'hypophosphite d'ammonium qui agit comme une source d'ammoniac et un agent réducteur en même temps. Au cours de l'optimisation, des différents paramètres ont été étudiés / Recently, requirements in chemistry are changing fast, since sustainable development has retained more attention. Green chemistry principles have promoted chemists to develop chemical products and processes that reduce or eliminate hazardous substances. The research work described in this thesis is focused on the development of new reducing systems using hypophosphites as substitutes for traditional toxic reducing agents.In order to achieve this goal, aromatic nitriles were reduced into the corresponding aldehydes by the formation of hydrogen gas and nickel nanoparticles upon combining a nickel precursor with calcium hypophosphite in the presence of base in a biphasic medium. Moreover, aromatic nitriles were reduced into primary amines using calcium hypophosphite and the heterogeneous catalyst palladium on carbon. The nature of the metal catalyst, additives, solvents, temperature, and concentrations were studied in details.On the other hand, the well-known direct reductive amination of aliphatic and aromatic ketones was done for the first time using heterogeneous palladium on carbon, and ammonium hypophosphite which acts as a source of ammonia and as a reducing agent at the same time. During optimization different parameters were studied
8

Synthesis and characterization of novel cellulosics

Dash, Rajalaxmi 30 August 2012 (has links)
The search for alternatives to the fossil-based products has dramatically surged during past few decades primarily due to the problems associated with the scarcity of these sources and global environmental concerns. Among those many alternatives, exploitation of cellulose, as a raw material to develop novel products has been a constant attempt since it has never lost its both economic and industrial impact. Cellulose is known for its significant contribution as a raw material and as a fascinating sustainable macromolecule, which exhibits wide availability and versatile chemical reactivity to discover novel derivatives for broad range of applications. Conversion of cellulose C2/C3 secondary hydroxyl groups to dialdehyde groups in the presence of periodate is an extremely useful method for regioselective oxidation of cellulose and to activate the polymer for further derivatization. This thesis is primarily focused on synthesis and characterization of wide range of cellulose derivatives exploiting facile periodate oxidation methodology. The first study investigated the use of periodate oxidation as a potential method to synthesize a novel water soluble derivative of cellulose from bleached hardwood Kraft pulp. The work focused on the effect of periodate oxidation and sulfonation reaction on water solubility, morphology and structure of cellulose fibers. The results showed a significant increase in water solubility (2.85 -28.5 g/L) and complete change in surface morphology of the fibers due to the introduction of sulfonic acid groups. In the second study, the same reaction scheme was employed on bead cellulose to prepare anionic 2,3-disulfonated beads. Due to the presence of negatively charged sulfonic acid groups, the beads were found to be agglomerated in presence of cationic starch, exhibiting their future application in chromatographic separation. In the third study, model primary amine compounds such as methyl and butyl amines were grafted to nanowhisker surfaces following periodate oxidation and reductive amination. Then, based on the grafting procedure, in the following study, gamma aminobutyric acid (spacer) and syringyl alcohol (linker) was attached to periodate oxidized nanowhiskers to synthesize a novel drug delivery system. The final study investigated the application of periodate oxidized nanowhiskers as chemical cross-linkers to stabilize gelatin gels. It was concluded that the chemical cross-linking has a significant effect on relative increase in percentage of rigid protons, reduced water uptake ability and reduced pore size of the gels. Not only did the chemical cross-linking improve the storage modulus of the gels (150%) and but it also increased the thermal resistance until 50 oC.
9

Novel Approaches For The Synthesis Of Amino Acids And Piperidines, Including Asymmetric Strategies

Vippila, Mohana Rao 07 1900 (has links) (PDF)
Chapter I deals with novel approaches for α-amino acids. This chapter has been divided into three sections. Section A describes the synthesis of α-amino acids via the Beckmann rearrangement of carboxyl-protected β-keto acid oximes. The synthesis of α-amino acids using the Beckmann rearrangement involves the preparation of the Z-oxime and efficient protection of the carboxyl group. Various 2-substituted benzoylacetic acids were synthesized, in which the carboxyl function was masked as a 2,4,10-trioxaadamantane unit (an orthoacetate), and were converted to their oximes (Scheme 1).1 The oximes were converted to the their mesylates, which underwent the Beckmann rearrangement with basic Al2O3 in refluxing CHCl3. The corresponding 2-substituted-N-benzoyl-α-amino orthoacetates were obtained in excellent overall yields. In Section B, the synthesis of α-amino acids via the Hofmann rearrangement of carboxyl-protected malonamic acids is described. The Hofmann rearrangement involves the migration of the alkyl moiety of the amide onto the N-centre. Various 2-substituted malonamic acids (malonic acid mono amides) were synthesized with the carboxyl group masked as a 2,4,10¬trioxaadamantane unit (an orthoacetate). These underwent the Hofmann rearrangement with phenyliodoso acetate and KOH/MeOH (Scheme 2). The resulting (N-methoxycarbonyl)¬trioxaadmantylmethylamines (carbamates) were formed in yields > 90%, and are α-amino acids with both carboxyl and amino protection.2 In Section C, an approach to chiral amino acids via the reductive amination of ketones, involving the hydride reduction of 1-(S)-phenethyl amine derived Schiff bases of C-protected α¬keto acids is described. An efficient synthesis of α-amino acids has thus been developed in high diastereoselectivity. Various 1-acyl-2,4,10-trioxaadamantanes were prepared from the corresponding 1-methoxycarbonyl derivatives, via conversion to the N-acylpiperidine derivative followed by reaction with a Grignard reagent in refluxing THF (Scheme 3). These α-keto orthoformates were converted to corresponding imines with 1-(S)-phenethyl amine (TiCl4/Et3N/toluene/reflux), the Schiff bases being reduced with NaBH4 (MeOH/0 °C) to the corresponding 1-(S)-phenethyl N-alkylamines (diastereomeric excess by NMR ~ 90:10).3 Hydrogenolysis of the phenethyl group (Pd-C/H2/MeOH) finally led to the (aminoalkyl)trioxaadamantanes, which are chiral C-protected α-amino acids, in excellent overall yields. Here a mild, inexpensive and efficient hydride reducing agent for the reductive amination of α-keto acids has been developed. Chapter II deals with the enantioselective synthesis of piperidines and its applications in the synthesis of piperidine alkaloids.4 This chapter has been divided into two sections. In Section A, the enantioselective synthesis of 2-substituted piperidines and its applications in the synthesis of (R)-(-)-coniine and (R)-(+)-anatabine are described. Various N-tert-butylsulfinyl imines were synthesized, which upon allyl Grignard addition followed by N-allylation gave the diallyl compound with good diastereoselectivity (Scheme 4). The diallyl compound underwent ring closing metathesis with Grubbs’ first generation catalyst and subsequent reduction of the double bond with H2-Pd/C, furnished N-sulfinyl-2-susbstituted piperidines. Using this methodology (R)¬(-)-coniine hydrochloride and (R)-(+)-anatabine were synthesized. In Section B, the enantioselective synthesis of (S)-tert-butyl 2-(2¬hydroxyethyl)piperidine-1-carboxylate and its elaboration to the synthesis of (S)-(+)-δ-coniceine and (S)-(+)-pelletierine are described. The (S)-tert-butyl 2-(2-hydroxyethyl)piperidine-1¬carboxylate is a synthon used for the synthesis of various 2-substituted piperidine natural products. Using the above methodology (S)-tert-butyl 2-(2-hydroxyethyl)piperidine-1¬carboxylate was synthesized starting from (S)-(+)-2-methyl-2-propanesulfinamide and 3¬(benzyloxy)propanal (Scheme 5). This alcohol was further elaborated to furnish two piperidine alkaloids (S)-(+)-pelletierine and (S)-(+)-δ-coniceine. Scheme 5. Enantioselective synthesis of (S)-tert-butyl 2-(2-hydroxyethyl)piperidine-1¬carboxylate, (S)-(+)-pelletierine and (S)-(+)-δ-coniceine. Chapter III deals with the formation of barbituric acid in an aprotic medium and related mechanistic studies. The generally accepted mechanism for the formation of barbituric acid involves the nucleophilic attack of urea anion on diethyl malonate.5 This is debatable for at least two reasons: (1) the normally employed base, sodium ethoxide, is too weak to deprotonate urea and (2) diethyl malonate is more acidic than urea, so the initial deprotonation by base has to be from diethyl malonate. When diethyl malonate (DEM) enolate was treated with urea in DMF, barbituric acid was formed in 61% yield. The reaction was also extended to several 2-substituted DEM derivatives, the corresponding substituted barbituric acids being formed in reasonable yields. The reaction between diethyl 2-(ethoxycarbonyl)malonate and urea, with potassium carbonate in refluxing ethanol, led to the formation of barbituric acid. This is apparently facilitated by hydrogen bonding involving the enolate oxygen atom, which renders one of the carbonyl groups relatively electrophilic (Scheme 6). Meldrum’s acid failed to react with urea, despite its greater acidity, indicating that the reaction requires the formation of the E from of the s-trans enolate ion, in which the hydrogen bonding interaction and nucleophilic attack can occur in concert. Scheme 6. Proposed transition state for formation of Barbituric acid. Chapter IV deals with an improved Erlenmeyer synthesis with 5-thiazolone and catalytic manganese (II) acetate for aliphatic and aromatic aldehydes. A serious limitation to the classical Erlenmeyer reaction is that it generally fails in the case of aliphatic aldehydes. This chapter describes a convenient approach to this problem that extends the scope of the Erlenmeyer synthesis. The present study was aimed at developing milder conditions for the synthesis of 4¬arylidene and alkylidenethioazlactones. Thus, N-(thiobenzoyl)glycine was treated with DCC in DCM at room temperature for 10 min., according to a reported procedure, to form the thioazlactone.6 The same reaction mixture was treated with catalytic Mn(II) acetate and an equivalent of an aromatic aldehyde, to furnish the corresponding 4-arylidenethioazlactones in good yields. The scope of the reaction was extended to alphatic aldehydes also under similar reaction conditions, to obtain the 4-alkylidene thioazlactones in good to moderate yields (Scheme 7). Scheme 7. The Erlenmeyer synthesis with 5-thiazolone and manganese acetate. (for figures & structural formula pl refer pdf file)
10

La liaison réversible NCO appliquée aux domaines de l'inhibition d'enzymes et des oligomères bio-mimétiques / The distinctive “NCO” interaction and its deliberate implication in drug design and in the development of a new archetype of foldamer

Gros, Guillaume 06 March 2015 (has links)
Cette thèse décrit le développement d’une gamme d’inhibiteurs de la protéase du VIH-1 et d’un oligomère bio-mimétique comportant en leur sein une ou plusieurs interactions réversibles entre une amine tertiaire et un carbonyle, appelée interaction NCO. Cette interaction est favorisée en milieu fortement protique polaire comme les milieux aqueux.Ces travaux ont permis de mettre au point une synthèse modulaire qui a donné lieu à l’obtention de 7 nouveaux candidats à l’inhibition de la protéase du VIH-1. Les modifications de synthèse ont notamment permis de travailler à de plus grandes échelles et d’apporter une grande versatilité à cette synthèse. Les candidats obtenus ont alors été testés in vitro et in cellulo avec une nouvelle méthode en collaboration avec Lorena Martinez et Pierre Falson, de l’Institut de Biologie et Chimie des Protéines (IBCP). Dans un deuxième temps, nous avons élaboré une nouvelle stratégie de synthèse d’un oligomère bio-mimétique. Plusieurs monomères et voies de synthèse ont été explorés et un tétramère a pu être isolé. Malheureusement, certains obstacles, notamment issus de la purification, ont limités les quantités obtenues ce qui n’a pas permis de pousser l’étude comportementale de ces oligomères. Les travaux présentés ici sont ceux de l’optimisation de la synthèse et des perspectives concernant ce sujet. Enfin ce manuscrit détaille le développement d’un nouveau procédé de synthèse permettant l’obtention de dérivés du 1,4,7-triazacyclononane présentant un motif de N-substitutions 2Ra/Rb, travail ayant abouti au dépôt d’un brevet. / This thesis relates the research performed on the design and synthesis of a new type of HIV-1 protease inhibitors and a new archetype of a bio-mimetic foldamer based on an unusual interaction, the NCO interaction. This interaction occurs between a tertiary amine and a carbonyl group in highly polar and protic media, such as aqueous media. The first half of my work focused on the development of a modular synthesis towards candidates for the inhibition of HIV-1 protease. This research enabled us to work on large scale and to be able to modify at will most of the candidates’ functions. Seven new inhibitors were isolated and tested in vitro and in cellulo with an original method, in collaboration with Lorena Martinez and Pierre Falson, from the Institute of Biology and Chemistry of Proteins (IBCP). The second half of my work was dedicated to the design of a new backbone for a bio-mimetic oligomer. A few strategies were explored and a monomer was chosen to be oligomerized. The coupling enabled the isolation of a tetramer. Unfortunately, serious purification issues limited the quantity of the previous tetramer and no foldamer study could be performed. The work presented here are the synthesis’ optimization and the perspectives to overcome the purification issues. In addition, a new process for the synthesis 1,4,7-triazacyclononanes displaying a 2Ra/Rb N-substitution pattern was developed from diethylenetriamine in only four steps. This work was patented during this PhD.

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