Thèses : « Organic Synthessis »

1

Paradis, Michel 1976. « The design and synthessis of platinum-based DNA intercalators / ». Thesis, McGill University, 2000. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=31523.

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Over the past years, considerable attention has focused on the synthesis of small complexes that can bind and react at specific DNA sequences. This understanding of how to target DNA sites with specificity becomes important for nucleotide probing and novel chemotherapeutics.
Inert and stable transition-metal complexes are already being used for this purpose. Square planar platinum (II) complexes containing an aromatic heterocyclic ligand can insert and stack between the double helix base pairs. Two known ligands, DPPZ and phi, do intercalate DNA when chelating ruthenium, rhodium, or osmium.
Here are presented the syntheses of [Pt(NH3)2DPPZ](CF 3SO3)2, [Pt(en)DPPZ](CF3SO3) 2, [Pt(phen)DPPZ](CF3SO3)2, [Pt(Me 2bpy)DPPZ](CF3SO3)2, and [Pt(phendione)DPPZ](CF 3SO3)2, and the attempted syntheses of [Pt(en)phi](PF 6)2 and [Pt(phen)phi](PF6)2. The binding constants of [Pt(NH3)2DPPZ](CF3SO3) 2 and [Pt(en)DPPZ](CF3SO3)2 to calf thymus DNA have been determined. The knowledge coming from the synthetic strategy to obtain monomers has allowed the synthesis of a platinum-based dimer, [(DPPZ)Pt{DPPZ(11-11 ')DPPZ}Pt(DPPZ)](CF3SO3)4, having two intercalative DPPZ ends. We hope that this bis-intercalator will bring into close proximity two DNA strands.

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Phung, Bich Tuyen. « Etude de la sélectivité dans la réaction de Buchner ». Electronic Thesis or Diss., Université Grenoble Alpes, 2024. https://theses.hal.science/tel-04651531.

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Le travail présenté dans ce manuscrit est divisé en deux grandes parties. Dans un premier temps, une étude sera présentée sur des problème de chimiosélectivité observés lors de la réaction de transfert de carbène. Des composés diazo différemment substitués ont été généré comme précurseur de carbène, et la réaction de transfert de carbène a été effectuée en présence de Rh2(OAc)4. Les résultats montrent une compétition entre la réaction de Buchner et l’insertion C‒H en position benzylique, dépendant de la substituant du diazo. Des calculs de DFT ont ensuite été réalisés pour compléter les informations obtenues expérimentalement. Le deuxième axe majeur de ce manuscrit a consisté à recherche une alternative aux composés diazo pour effectuer des additions de carbènes asymétriques sur des composés aromatiques. Des précurseurs de type N-sulfonyle-1,2,3-triazole ont été synthétisé en utilisant la méthode de CuAAC. La réaction intermoléculaire de cycloaddition [3+2] formelle avec des aromatique catalysés par des complexes Rh(II) chiraux a ensuite été étudié
The work presented in this manuscript is divided into two main parts. Firstly, a study about the problem of chemoselectivity during the intramolecular carbene transfer reaction will be presented. The diazo compound bearing different substituent was synthesized as precursor of carbene, and then the carbene transfer reaction was performed in the presence of the Rh2(OAc)4 catalyst. The result displayed the competition between Buchner reaction and C‒H insertion reaction at benzylic position, depended on the substituent. DFT calculations were subsequently conducted to complete the information obtained experimentally. The second major focus of this manuscript involves exploring the reactivity of N-sulfonyl-1,2,3-triazole. N-sulfonyl-1,2,3-triazole precursors were generated using the CuAAC method. The intermolecular formal [3+2] cycloaddition reaction with aromatics catalysed by chiral Rh(II) was then studied

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Trupina, Snjezana. « Synthesis of Metalloporphyrins with Oligothiophenes as Probes for Amyloid Diseases ». Thesis, Linköping University, Linköping University, Organic Chemistry, 2010. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-57989.

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Abnormal aggregation of misfolded proteins is related to numerous neurodegenerative diseases, which include Alzheimer’s, Parkinson’s disease and prion diseases. Luminescent conjugated probes (LCPs) have been used as dyes for these supramolecular assemblies termed amyloid fibrils. To these probes, metalloporphyrin (MP) derivates have been attached to achieve new spectroscopic properties, which will allow for new ways to study protein aggregation diseases.

In this thesis the synthesis of two different LCPs anchored porphyrin derivates are described. The LCPs are synthesized from 3-thiopheneacetic acid and additional thiophene units are added with the use of Suzuki cross coupling reaction. The porphyrin is synthesized from pyrrol, benzaldehyde and methyl-4- formylbenzoate in a condensation reaction. In the first target molecule (TM) the porphyrin and thiophene are coupled with a spacer and the second one is a direct coupling between the two compounds.

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Tilliet, Mélanie. « Synthesis and study of new oxazoline-based ligands ». Doctoral thesis, KTH, Organisk kemi, 2008. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-4858.

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This thesis deals with the study of oxazoline-based ligands in metal-catalyzed asymmetric reactions. The first part describes the synthesis of six new bifunctinal pyridine-bis(oxazoline) ligands and their applications in asymmetric metal-catalysis. These ligands, in addition to a Lewis acid coordination site, are equipped with a Lewis basic part in the 4-position of the oxazoline rings. Dual activation by means of this system was probed in cyanide addition to aldehydes. The second part is concerned with the synthesis of two pyridine-bis(oxazoline) ligands bearing bulky triazole groups in the 4-position of the oxazoline rings and a macrocyclic ligand consisting of a pyridine-bis(oxazoline) moiety and a diaza-18-crown-6 ether. The synthesis of these compounds benefits from the use of “click chemistry”. The ligands thus obtained were tested in different asymmetric catalytic reactions. Complexation studies with different bifunctional molecules that could bind into the cavity of the macrocycle were carried out using NMR spectroscopy. A third chapter is devoted to the synthesis of a supported pyridine-bis(oxazoline) catalyst and its use in catalysis. The pyridine-bis(oxazoline) ligand was efficiently connected to a polystyrene resin via a robust triazole linker. This resin could be employed in different metal-catalyzed asymmetric reactions and good results were obtained in terms of yield and enantioselectivity. Moreover, this polymer-bound ligand could be easily and efficiently recycled. Finally, the last part deals with the use of a hydroxy-containing phosphinooxazoline ligand in the hydrosilylation of imines and in the asymmetric intermolecular Heck reaction. A cationic iridium complex of this ligand was studied by NMR spectroscopy.
QC 20100914

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Winberg, Karl Johan. « Carborane Derivatives for Nuclide Therapy and Imaging : Synthesis and Radio-labelling ». Doctoral thesis, Uppsala : Acta Universitatis Upsaliensis : Univ-bibl. [distributör], 2003. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-3561.

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Fyrner, Timmy. « Synthesis of Structures Related to Antifreeze Glycoproteins ». Thesis, Linköping University, The Department of Physics, Chemistry and Biology, 2005. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-11941.

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In this thesis, synthesis of structures related to antifreeze glycoproteins (AFGPs) are presented. Synthetic routes to a protected carbohydrate derivative, 2,3,4,6-tetra-O-benzyl-β-galactopyranosyl-(1→3)-2-deoxy-2-azido-4,6-di-O-benzyl-β-D-thio-1-galactopyranoside, and a tBu-Ala-Thr-Ala-Fmoc tripeptide, are described. These compounds are meant to be used in the assembly of AFGPs and analogues thereof. A Gal-GlcN disaccharide was synthesized via glycosylation between the donor, bromo-2-O-benzoyl-3,4,6-tri-O-benzyl-α-Dgalactopyranoside, and acceptor, ethyl 4,6-O-benzylidene-2-deoxy-2-N-phthalimido-β-D-1-thio-glucopyranoside, using silver triflate activation. Subsequent epimerization to a Gal-GalN disaccharide was achieved using Moffatt oxidation followed by L-selectride® reduction. The tripeptide was synthesized in a short and convenient manner using solid phase peptide synthesis with immobilized Fmoc-Ala on Wang® resins as starting point.

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7

Larsson, Andreas. « Synthesis, structure and conformation of oligo- and polysaccharides ». Doctoral thesis, Stockholm University, Department of Organic Chemistry, 2004. http://urn.kb.se/resolve?urn=urn:nbn:se:su:diva-172.

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Carbohydrates are a complex group of biomolecules with a high structural diversity. Their almost omnipresent occurrence has generated a broad field of research in both biology and chemistry. This thesis focuses on three different aspects of carbohydrate chemistry, synthesis, structure elucidation and the conformational analysis of carbohydrates.

The first paper describes the synthesis of a penta- and a tetrasaccharide related to the highly branched capsular polysaccharide from Streptococcus pneumoniae type 37. In the second paper, the structure of the O-antigenic repeating unit from the lipopolysaccharide of E. coli 396/C1 was determined along with indications of the structure of the biological repeating unit. In addition, its structural and immunological relationship with E. coli O126 is discussed. In the third paper, partially protected galactopyranosides were examined to clarify the origin of an intriguing ⁴J_HO,H coupling, where a W-mediated coupling pathway was found to operate. In the fourth paper, the conformation of methyl a-cellobioside is studied with a combination of molecular dynamics simulations and NMR spectroscopy. In addition to the expected syn-conformation, detection and quantification of anti-ø and anti-ψ conformers was also possible.

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Esfandiarfard, Keyhan. « Novel Organophosphorus Compounds for Materials and Organic Synthesis ». Doctoral thesis, Uppsala universitet, Molekylär biomimetik, 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-328295.

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This thesis is devoted to the development of new organophosphorus compounds for potential uses in material science and as reagents in Organic Chemistry. Organophosphorus compounds in a single molecule or organic electronics context are appealing as the phosphorous centers perturb the electronic properties of the π-conjugated systems while at the same time provide synthetic handles for subsequent synthetic modifications. As such, new synthetic methodology to such compounds and the exploration of new building blocks is of considerable interest. In a different study, novel organophosphorus compounds are synthesized and shown to promote a reaction in Organic Chemistry that has previously not been possible, i.e. the stereoselective reductive coupling of aldehydes to alkenes. Such developments enlarge the toolkit of reactions that are available to Organic Chemists, and may impact the synthetic routes to pharmaceuticals and other important commodity chemicals. A general introduction of the key structural unit of this thesis, phosphaalkenes, is given in the first chapter. The synthesis, reactivity, properties and applications of these P=C double bond containing compounds are highlighted. The Wittig reaction and its variations as well as the phosphorus analogues that produce phosphaalkenes are outlined in detail. The second chapter is dedicated to the synthesis of a precursor that is used for the preparation of novel π-conjugated, organophosphorus compounds. C,C-Dibromophosphaalkenes are prepared and the halide substituents are used for the selective introduction of acetylene units. Besides the phosphaalkenes, the successful syntheses of two new diphosphenes is presented, indicating a broad applicability of the precursors. The third chapter is dedicated to the isolation of a metal-free phosphanylphosphonate that transforms aldehydes quantitatively to their corresponding E-phosphaalkenes in a transition metal-free phospha-HWE (Horner-Wadsworth-Emmons) reaction. The reaction benefits from mild conditions, high E-stereoselectivity, and a broad substrate scope. In the last chapter, a novel method for the reductive coupling of aldehydes to olefins is introduced. The reaction, which is a vast improvement over the McMurry coupling, allows for the selective synthesis of symmetrical and most importantly unsymmetrical E-alkenes. The phosphanylphosphonate mentioned above is the reagent that facilitates the coupling of the aldehydes via a phosphaalkene intermediate. This one-pot reaction benefits from mild conditions, good conversions, and high E-stereoselectivity. In summary, the thesis presents novel aspects of organophosphorus chemistry. These include the preparations and exploration of interesting precursors for the construction of π-conjugated organophosphorus compounds, and the use of organophosphorus reagents for unprecedented transformations in Organic Chemistry.

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BERTON, GIACOMO. « SYNTHESIS OF TRIPHENYLENES FOR SUPRAMOLECULAR APPLICATIONS ». Doctoral thesis, Università degli Studi di Trieste, 2020. http://hdl.handle.net/11368/2969361.

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In this Doctoral Thesis, through several examples of new chemical modifications characterized by high yields and selectivities and new supramolecular structures, held together by a wide range of intermolecular forces forming several new host systems, we reached our target to revamp triphenylene and derivatives as a new molecular scaffold in supramolecular chemistry. More specifically, the introduction in our triphenylenic scaffold of alkyl thiol chains allowed the formation of sulphide and disulphide covalent cages, while by insertion of pyridine moieties through Mannich reaction it was possible to obtain transition metal coordination cages upon addition of metal corners. The creation of a tris-acid from the original scaffold allowed the investigation of self-aggregation capsules through hydrogen bonds between carboxylic acids, and the functionalization with charged polytails attached to the central triphenylenic core, alternated with apolar substituents, allowed solubilization in water with the formation of very small micelles. Moreover, the interaction between positively charged and negatively charged triphenylenes permitted the creation of peculiar ionic hetero-dimeric capsules. We are sure that this will spur future investigation on the capsules and cages presented in this work, enriching the scientific community involved in this interdisciplinary field of research.

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10

Hagberg, Daniel. « Synthesis of Organic Chromophores for Dye Sensitized Solar Cells ». Licentiate thesis, Stockholm : Kemi, Kungliga Tekniska högskolan, 2007. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-4600.

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11

Gemma, Emiliano. « Synthesis of Oligosaccharides for Interaction Studies with Various Lectins ». Doctoral thesis, Stockholm : Department of Organic Chemistry, Stockholm University, 2005. http://urn.kb.se/resolve?urn=urn:nbn:se:su:diva-459.

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Eriksson, Tor. « Synthesis of 2-(ethoxy(hydroxy)phosphoryl)-3-phenylpropyl ethanethioate ». Thesis, Uppsala universitet, Institutionen för kemi - BMC, 2019. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-386474.

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Velikyan, Irina. « Synthesis, Characterization and Application of 68Ga-labelled Peptides and Oligonucleotides ». Licentiate thesis, Uppsala University, Department of Chemistry, 2004. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-86136.

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The positron emitting 68Ga radionuclide (T1/2 = 68 min) has the potential of practical interest for clinical PET. The metallic cation, 68Ga3+, is suitable for complexation reactions with chelators either naked or conjugated with macromolecules such as peptides and oligonucleotides. Such labeling procedures require pure and concentrated radiometal preparations, which cannot be sufficiently fulfilled by the presently available 68Ge/68Ga generator eluate. This thesis presents a method to increase the concentration and purity of 68Ga obtained from a commercial 68Ge/68Ga generator. DOTATOC (DOTA = 1,4,7,10-tetraazacyclo-dodecane-1,4,7,10-tetraacetic acid, TOC = D-Phe1-Tyr3–Octreotide) was used as a test molecule for comparing the labeling properties of different 68Ga preparations. In addition, DOTA-RDG (RGD = Cys2-6; c[CH2CO-Lys(DOTA)-Cys-Arg-Gly-Asp-Cys-Phe-Cys]-CCX6-NH2) and NODAGATATE (NODAGA = 1,4,7-triazacyclononane-1,4,7-triacetic, TATE = Tyr3 - Octreotate) were used to prove the concept. The use of the concentrated and purified 68Ga eluate along with microwave activation allowed quantitative 68Ga-labelling of peptide conjugates of ≤1 nanomolar quantities within 10 min. The specific radioactivity of the radiolabelled peptides was improved by a factor of >100 compared to previously applied techniques using non-treated generator eluate and conventional heating. A commercial 68Ge/68Ga generator in combination with this method for purification, concentration and microwave activated labeling resulted in a kit technology for 68Ga-tracer production.Four 17-mer oligonucleotides modified and functionalised with an hexylamine group in the 3'- or 5'- position were conjugated with DOTA and labelled with 68Ga using microwave activation. Chemical modification of the oligonucleotide backbone or sugar moiety did not influence the labelling nor the hybridisation ability of the oligonucleotides. However, the radioactivity organ biodistribution in rats differed dependent on the oligonucleotide structure. This indicated that metabolism and non-specific binding were affected by the backbone and sugar moiety structure.

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Ayesa, Alvarez Susana. « Design and Synthesis of Amine Building Blocks and Protease Inhibitors ». Doctoral thesis, Stockholm : Department of Organic Chemistry, Stockholm University, 2008. http://urn.kb.se/resolve?urn=urn:nbn:se:su:diva-8038.

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Wallner, Olov. « Palladium-Catalyzed Synthesis and Transformations of Organometallic Compounds ». Doctoral thesis, Stockholm : Dept. of Organic Chemistry, Stockholm University, 2006. http://urn.kb.se/resolve?urn=urn:nbn:se:su:diva-804.

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Torssell, Staffan. « Amino Aacohols : stereoselective synthesis and applications in diversity-oriented synthesis ». Licentiate thesis, KTH, Chemistry, 2005. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-315.

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This thesis is divided into three separate parts with amino alcohols as the common feature. The first part describes the development of a novel three-component approach to the synthesis of α-hydroxy-β-amino esters. Utilizing a highly diastereoselective Rh(II)-catalyzed 1,3-dipolar cycloaddition of carbonyl ylides to various aldimines, syn-α-hydroxy-β-amino esters formed in high yields and excellent diastereoselectivities. This methodology was also applied in a short enantioselective synthesis of the C-13 side-chain of Taxol.

The second part of the thesis describes a total synthesis of D-erythro- Sphingosine based on a cross-metathesis approach to assemble the polar head group and the aliphatic chain.

The last part deals with the application of amino alcohols as scaffolds in a diversity-oriented protocol for the development of libraries of small polycyclic molecules. The design of the libraries is based on the iterative use of two powerful ring-forming reactions; a ring-closing metathesis and an intramolecular Diels-Alder reaction, to simultaneously introduce structural complexity and diversity.

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Ahmed, Mustafe. « Synthesis of imidazopyridazine analogs aiming to improve antibacterial Gram-negative activity ». Thesis, Uppsala universitet, Institutionen för läkemedelskemi, 2021. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-449572.

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Modin, Judit. « Synthesis and Evaluation of Photoactive Pyridine Complexes for Electron Transfer Studies and Photoelectrochemical Applications ». Doctoral thesis, Uppsala : Acta Universitatis Upsaliensis, 2005. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-6146.

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O'Neill, Bridget. « Syntheses of novel 2-oxo esters : enzyme substrates designed for asymmetric synthesis ». Thesis, University of Bristol, 1995. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.261316.

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Lamprianidis, Panagiotis. « Photoredox catalysis with 10-phenyl-10H- phenothiazine and synthesis of a photocatalytic chiral proline-based organocatalyst ». Thesis, KTH, Organisk kemi, 2020. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-293510.

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Photoredox catalysis applications for the purpose of new synthetic routes in organic and sustainable chemistry are hot topics in organic synthesis today. In the present study, the synthesis of a chiral proline-based organocatalyst functionalized with 10-phenyl-10H phenothiazine (PTH) photocatalytic moietiesis investigated and attempted for the first time. PTH, an organic photocatalyst, isstudied for its photocatalytic activity in different organic reactions, such as dehalogenation of aromatic halides and the pinacol coupling reaction between aromatic aldehydes. These transformations are otherwise difficult to achieve without a suitable catalyst and the reactions were performed with moderate to high yields.
Applikationer av photoredox-katalys med syftet att generera nya syntetiska vägar inom organisk och hållbar kemi är populära ämnen i organisk syntes idag. I denna studien undersöktes för första gången syntesen av en kiral prolinbaserad organokatalysator som är funktionaliserad med fotokatalytiska enheter (10-fenyl-10H-fenotiazin (PTH)). Den fotokatalytiska aktiviteten av PTH studerades för olika organiska reaktioner, såsom t.ex. dehalogenering av aromatiska halider och pinacolkopplingar mellan aromatiska aldehyder. Dessa transformationer är annars svåra att uppnå utan en lämplig fotokatalysator och reaktionerna utfördes med måttliga till höga utbyten.

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Alfredsson, Maria. « Synthesis and Characterization of Acrylfentanyl Metabolites ». Thesis, Linköpings universitet, Kemi, 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-138142.

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Acrylfentanyl is a synthetic opioid that has been widely used in the last year. To help in the fight against synthetic drugs two potential metabolites of acrylfentanyl, one monohydroxy and one dihydroxy were synthesized. These metabolites will hopefully later be implemented in the analytical methods for metabolites of acrylfentanyl in urine by the Swedish National Board of Forensic Medicine. To have metabolites for analysis are very important as they are the main target in drug testing. The method used to synthesize the metabolites is a five-step synthesis with an additional 6th step for the dihydroxy metabolite. The methods used in the synthesis includes protection of amine with tert-butyloxycarbonyl, reductive amination with sodium triaceto boronhydride, alkylation and demethylation with boron tribromide. The methods used produced good results with high yields in nearly all steps.

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Erlandsson, Maria. « Imaging of Enzymes in the Steroid Biosynthetic Pathway : Synthesis of 18F-Labelled Tracers ». Doctoral thesis, Uppsala universitet, Organisk kemi, 2009. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-89177.

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This thesis deals with the synthesis and development of 18F-labelled alkyl etomidate and vorozole analogues, and their use as positron emission tomography (PET) tracers for the imaging of the steroid enzymes 11β-hydroxylase and aromatase. Two synthetic 18F-labelling approaches to the etomidate and vorozole analogues were developed, and the analogues were evaluated in some biological assays. The two-step labelling method was used to synthesise many compounds for biological evaluation. In the first step, a 18F-labelled intermediate based on a ditosylate or a halogenated diethyl ether was synthesised and used directly in the next alkylation step. The decay-corrected (d.c.) radiochemical yield was higher compared to other known two-step labelling methods. Once an appropriate candidate has been chosen for clinical evaluation, a one-step labelling method will be more suitable. We therefore developed a method based on precursors that had leaving groups at the end of their alkyl chains, and used these directly in the 18F-labelling synthesis. The one-step 18F-labelling synthesis required less reaction time and produced higher specific radioactivity and d.c. radiochemical yield than our two-step synthesis. With microwave heating, the reaction time was reduced to seconds and the d.c. radiochemical yield was better than that obtained with conventional heating. The one-step synthesis simplified the technical handling by allowing the tracer syntheses to be automated on the TRACERLab FXFN.

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Santangelo, Ellen M. « Stereoselective syntheses of semichemicals : Applications in ecological chemistry ». Doctoral thesis, KTH, Chemistry, 2004. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-74.

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This thesis describes the syntheses of semiochemicals and their applications in the development of control methods for pest insects. The compounds synthesized are divided into three groups: 1) Lepidoptera pheromones; 2) methyl substituted chiral pheromones and 3) aphid pheromones.

Different purification techniques have been explored in order to provide > 99% pure semiochemicals for field tests. Examples of the techniques are uses of urea inclusion complexes, argentum chromatography, low temperature crystallization and what we call the Baeckström isolation technique.

Iridoids have been produced in a synthetic strategy including an intramolecular enal-enamine [4+2] cycloaddition, a dynamic acetylation and an enantioselective transesterification mediated by a lipase from Pseudomonas cepacia. The use of chiral auxiliaries to perform the intramolecular [4+2] cycloaddition has also been investigated. A useful asymmetric route to iridoids has been developed.

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Karimi, Farhad. « [11C]Carbon Monoxide in Palladium- / Selenium-Promoted Carbonylation Reactions : Synthesis of 11C-Imides, Hydrazides, Amides, Carboxylic Acids, Carboxylic Esters, Carbothioates, Ketones and Carbamoyl Compounds ». Doctoral thesis, Uppsala universitet, Avdelningen för organisk kemi, 2002. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-2931.

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[11C]Carbon monoxide in low concentrations has been used in palladium- or seleniummediated carbonylation reactions such as the synthesis of 11C-imides, hydrazides, amides, carboxylic acids, esters, carbothioates, ketones and carbamoyl compounds. In these reactions aryl iodides have been used in most cases. However, less reactive aryl triflate, chloride and bromides were activated using tetrabutylammonium iodide. The reactivities of nucleophiles may have influence on the radiochemical yield of the 11Clabelled compounds. Carboxyamination of aryl halides using aniline derivatives yielded 10% of the corresponding 11C-amide. However, the radiochemical yields increased significantly when the aniline derivatives were treated with lithium bis(trimethylsilyl)amide. In contrast, this reagent did not improve the radiochemical yields when primary amines such as methylamine and benzylamine were used. In these cases the radiochemical yields were improved by using pempidine. 11C-Esterification usually gave low yields. However, the radiochemical yields of 11C-esters could be improved by using magnesium bromide and pempidine. An excess of ligand may have a significant impact on palladium-promoted carbonylation reaction. The radiochemical yields of 11C-ketones were improved when using excess amounts of tri-o-tolylphosphine. (13C)Carbon monoxide may be utilized for the synthesis of 13C-substituated compounds in order to confirm the position of 11C-labelling.

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Sjölin, Olof. « Synthesis of Substituted Pyrrolidines ». Thesis, KTH, Skolan för kemivetenskap (CHE), 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-207056.

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The task of medicinal chemists in a drug discoveryproject is to synthesize/design analogues to the screening hits, simultaneouslyincreasing target potency and optimizing the pharmacological properties. This requires a wide selection of moleculesto be synthesized, where both synthetic feasibility and price of startingmaterials are of great importance. In this work, a synthetic pathway from cheapand readily available starting materials to highly modifiable 2,4-disubstitutedpyrrolidines is demonstrated. Previously reported procedures to similarpyrrolidines use expensive catalysts, requires harsh conditions and requiresnon-commercially available starting materials. The suggested pathway herein has demonstrated great possibility forvariation in the 4-position, including fluoro, difluoro, nitrile and alcoholfunctional groups. There are several areas in which the synthesis can beimproved and expanded upon. Improvements can be made by optimizing thedescribed reaction conditions and further expansion of possible modificationsin both 2- and 4-position could be explored.

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Sonesten, Victor. « Design and Synthesis of Macrocyclic Peptides as Potential Inhibitors of Lysine-Specific Demethylase 1 ». Thesis, Uppsala universitet, Institutionen för kemi - BMC, 2019. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-397428.

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Toom, Lauri. « Bispidine Derivatives : Synthesis and Interactions with Lewis Acids ». Doctoral thesis, Uppsala : Acta Universitatis Upsaliensis : Universitetsbiblioteket [distributör], 2006. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-6735.

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Thorstensson, Fredrik. « Structure-Based Design and Synthesis of Protease Inhibitors Using Cycloalkenes as Proline Bioisosteres and Combinatorial Syntheses of a Targeted Library ». Doctoral thesis, Linköping : Linköpings universitet, 2005. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-4938.

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Teodorovic, Peter. « Synthesis of oligosaccharides related to the capsular polysaccharide of Neisseria meningitidis serotype A ». Doctoral thesis, Stockholms universitet, Institutionen för organisk kemi, 2005. http://urn.kb.se/resolve?urn=urn:nbn:se:su:diva-545.

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In order to find suitable stable vaccine candidates against Neisseria meningitidis group A, several structures related to the capsular polysaccharide have been synthesised. The first part of the thesis describes the synthesis of C-phosphonate analogues starting from glucose. The key step is a Mitsunobu coupling of a methyl C-phosphonate monomer to the 6-hydroxyl group of a 2-acetamido mannose derivative. Contained within this work is a description of an improved synthesis of 2-azido-2-deoxy-D-mannopyranose. The second part outlines the synthesis of structural elements present in the native capsular polysaccharide of Neisseria meningitidis serotype A including different acetylation and phosphorylation patterns. The final chapter describes an improved synthesis of the Lewis b hexasaccharide needed for purification of and interaction studies with the Helicobacter pylori adhesin BabA.

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Adrian, Meredith Jenny. « Design and Synthesis of Inhibitors Targeting the Aspartic Proteases HIV-1 PR and BACE-1 ». Doctoral thesis, Stockholms universitet, Institutionen för organisk kemi, 2009. http://urn.kb.se/resolve?urn=urn:nbn:se:su:diva-29773.

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This thesis describes the synthesis of molecules designed for inhibition of two aspartic proteases, viral HIV-1 PR and human BACE-1. It also reports on the structure activity relationships of the targeted enzyme inhibitors. It is estimated that currently 33 million people are infected with HIV, the causative agent of AIDS. The virus targets T-lymphocytes and macrophages of the human immune system. The HIV-1 PR plays an important role in the viral replication, and by inhibiting the enzyme the disease progression can be slowed down or even halted. Herein is reported the design and synthesis of a series of HIV-1 PR inhibitors with novel P2 substituents of which several inhibit the enzyme in the nanomolar range. The aim of the second work was to further develop the inhibitors by the introduction of fluorine. Several attempts were performed to fluorinate different P2-substituents. Alzheimer’s disease (AD) is neurodegenerative, progressive and fatal disorder of the brain. It is associated with accumulation of plaques and tangles that cause impairment and functional decline of brain tissue which result in loss of memory and cognition. The plaques are mainly constituted of amyloid-β peptides that are generated in two steps from the amyloid precursor protein (APP). The cleavage sequence is initiated by the aspartic protease BACE-1, which makes the enzyme a key target in the effort of finding a therapy that aim to slow down the progression of AD. Herein are enclosed the development of two series of potent BACE-1 inhibitors. In the first work a synthetic strategy was developed to truncate a previously reported hydroxyethylene core structure in order to generate more drug-like inhibitors. This generated a series of truncated inhibitors where two amide bonds have been replaced with an ether - or alternatively a secondary amine linkage. A number of these inhibitors show potency against BACE-1. In the second part of the work the aim was investigate the effect of alterations in the P1 position. Five scaffolds with new P1 substituents were designed, synthesized and coupled with two different P2-P3 substituents. This resulted in a series of potent inhibitors that inhibit BACE-1 in the nanomolar range.
At the time of the doctoral defense, the following papers were unpublished and had a status as follows: Paper 1: Submitted. Paper 2: Submitted. Paper 3: Manuscript.

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Kalek, Marcin. « Synthesis of C(sp2)-P bonds by palladium-catalyzed reactions : Mechanistic investigations and synthetic studies ». Doctoral thesis, Stockholms universitet, Institutionen för organisk kemi, 2011. http://urn.kb.se/resolve?urn=urn:nbn:se:su:diva-56467.

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This thesis focuses on synthetic and mechanistic aspects of palladium-catalyzed C(sp2)-P bond-forming reactions, with the aim to develop mild and efficient methods for the synthesis of biologically active phosphorus compounds, e.g. DNA analogs. The first part of the thesis is devoted to detailed mechanistic investigations of the palladium-catalyzed C-P cross-coupling reaction, in order to fully understand the underlying chemistry and by rational design of the reaction conditions, improve the overall efficiency of the process and broaden its applicability. In particular influence of palladium coordination by different anions on the rate of ligand substitution and reductive elimination steps of the reaction was studied. It was found that coordination of acetate ion results in unprecedented acceleration of both of the mechanistic steps, what leads to remarkable shortening of the overall reaction times. In-depth kinetic investigations enabled to ascribe the observed effects to ability of the acetate ion to act as a bidentate ligand for palladium. This causes considerable alternation of the reaction mechanism, comparing to the reaction involving halide-containing complexes, and results in significant rate increase. Based on the above mechanistic studies an efficient method for the synthesis of arylphosphonates, using substoichiometric amounts of inorganic acetate additive and reduced amount of catalyst, was developed. In the next part of the thesis, efforts to further enhance the palladium-catalyzed cross-coupling efficiency by using a microwave-assisted synthesis are described. These explorations resulted in a successful development of two protocols, one for a cross-coupling of H-phosphonates and the other for H,H-phosphinates, under the microwave heating conditions. Application of this energy source resulted in extremely short reaction times, measured in minutes. The final chapter of this thesis deals with studies on palladium-catalyzed SN2’ propargylic substitution reaction with phosphorus nucleophiles, which leads to allene products. Efficient procedure for the synthesis of allenylphosphonates and related compounds was developed. The method enables full control of stereochemistry in the allene moiety and at the asymmetric phosphorus center. Some conclusions on the mechanism of the reaction were also drawn.
At the time of the doctoral defense, the following paper was unpublished and had a status as follows: Paper 7: In press.

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Tan, Changqing. « Photochemical Silaylide, Silylene and Silene Syntheses ». Thesis, University of North Texas, 1990. https://digital.library.unt.edu/ark:/67531/metadc501256/.

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The synthesis of o-(N,N-dimethylamino)methylphenyl tris (trimethylsilyl) silane (II), a photochemical precursor of o- (N,N-dimethylamino) methylphenyl (trimethylsilyl) sila ammonium ylide (intramolecular silylene complex) and otolyl(trimethylsilyl)silylene is reported. Photolysis of II at room temperature in a cyclohexane solution of triethyl silane produced the silylene ylide and the presumably uncomplexed isomer, a silylene, which is trapped to afford the 2-(o-(N,N-dimethylamino)methylphenyl) -1,1,1-triethyl 3,3,3-trimethyltrisilane, 33% yield. A second decomposition pathway, a photodeamination, produced o-tris(trimethyl silyl) silyltoluene. UV spectra of the silaammonium ylide formed in the photochemical reaction of II was observed at 77k in hard or soft matrices.

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33

Ericsson, Cecilia. « Synthesis of Tetrahydrofuran and Pyrrolidine Derivatives Utilising Radical Reactions : Organochalcogenides in Reductive, Carbonylative and Group-Transfer Cyclisation ». Doctoral thesis, Uppsala : Acta Universitatis Upsaliensis : Univ.-bibl. [distributör], 2004. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-4018.

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Karimi, Farhad. « [¹¹C]Carbon Monoxide in Palladium- / Selenium-Promoted Carbonylation Reactions : Synthesis of ¹¹C-Imides, Hydrazides, Amides, Carboxylic Acids, Carboxylic Esters, Carbothioates, Ketones and Carbamoyl Compounds ». Doctoral thesis, Uppsala University, Organic Chemistry, 2002. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-2931.

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[¹¹C]Carbon monoxide in low concentrations has been used in palladium- or seleniummediated carbonylation reactions such as the synthesis of ¹¹C-imides, hydrazides, amides, carboxylic acids, esters, carbothioates, ketones and carbamoyl compounds.

In these reactions aryl iodides have been used in most cases. However, less reactive aryl triflate, chloride and bromides were activated using tetrabutylammonium iodide.

The reactivities of nucleophiles may have influence on the radiochemical yield of the ¹¹Clabelled compounds. Carboxyamination of aryl halides using aniline derivatives yielded 10% of the corresponding ¹¹C-amide. However, the radiochemical yields increased significantly when the aniline derivatives were treated with lithium bis(trimethylsilyl)amide. In contrast, this reagent did not improve the radiochemical yields when primary amines such as methylamine and benzylamine were used. In these cases the radiochemical yields were improved by using pempidine.

¹¹C-Esterification usually gave low yields. However, the radiochemical yields of ¹¹C-esters could be improved by using magnesium bromide and pempidine.

An excess of ligand may have a significant impact on palladium-promoted carbonylation reaction. The radiochemical yields of ¹¹C-ketones were improved when using excess amounts of tri-o-tolylphosphine.

(¹³C)Carbon monoxide may be utilized for the synthesis of ¹³C-substituated compounds in order to confirm the position of ¹¹C-labelling.

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35

Larsson, Michael. « Natural products from nonracemie building blocks : synthesis of pine sawfly pheromones ». Doctoral thesis, KTH, Kemi, 2005. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-128.

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This thesis describes a number of synthetic approaches for obtaining chiral, enantiomerically pure natural products, in particular some semiochemicals. This has been accomplished by using various strategies; by starting from compounds from the chiral pool, by using chiral auxiliaries, via enzymatic resolutions or by chemical asymmetric synthesis. Hence, the sexual pheromone of Microdiprion pallipes, a propanoate ester of one or several isomers of 3,7,11-trimethyltridecan-2-ol, was synthesised, both as a mixture of all isomers and as the sixteen pure, individual stereoisomers. These compounds were obtained by joining different enantiopure building blocks stemming from the chiral pool. When compared with some synthetic blends, both the propanoate esters of the stereoisomeric erythro-3,7,11-trimethyltridecan-2-ols originally found in the extract from the female of M. pallipes, surprisingly, showed lower activities in biological studies. Indeed, the propanoates of two threo-isomers gave significantly higher responses in biological tests, than did the propanoates of the two natural erythro-ones. Because the synthetic strategy used earlier was not very efficient for the preparation of the threo-isomers of 3,7,11-trimethyltridecan-2-ol, we were encouraged to look for alternative synthetic approaches. The new synthetic strategy chosen led us to two key synthetic building blocks, an O-protected derivative of (2S,3S)-3-methyl-4-(phenylsulfonyl)butan-2-ol butanol and (3R,7R)-1-iodo-3,7-dimethylnonane. Deprotonation of the former followed by alkylation with the latter should give a compound with the desired carbon skeleton. For efficient preparation of the first building block, we developed a new diastereoselective addition reaction of dialkylzincs to some chiral aldehydes, the products of which were diastereomerically enriched 1,2-dialkyl-alkanols. Using this method, each enantiomer of the desired building block was obtained via efficient diastereoselective addition of dimethylzinc to each enantiomer of a 2-methylaldehyde. The resulting product, a diastereomerically and enantiomerically highly enriched 3-methyl-2-alkanol was further purified by enzyme catalysed acylation followed by some functional group interconversions. The second building block was prepared via convergent multistep synthesis, starting from a single, enantiomerically pure compound, (R)-2-methylsuccinic acid 4-t-butyl ester, derived from the chiral pool. The two enantiomerically pure building blocks, so obtained, were coupled together. Some additional functional group manipulations of the product produced furnished the desired isomer, which had shown the highest activity in field tests of the M. pallipes, namely the propanoate ester of (2S,3R,7R,11R)-3,7,11-trimethyltridecan-2-ol. This thesis describes a number of synthetic approaches for obtaining chiral, enantiomerically pure natural products, in particular some semiochemicals. This has been accomplished by using various strategies; by starting from compounds from the chiral pool, by using chiral auxiliaries, via enzymatic resolutions or by chemical asymmetric synthesis. Hence, the sexual pheromone of Microdiprion pallipes, a propanoate ester of one or several isomers of 3,7,11-trimethyltridecan-2-ol, was synthesised, both as a mixture of all isomers and as the sixteen pure, individual stereoisomers. These compounds were obtained by joining different enantiopure building blocks stemming from the chiral pool. When compared with some synthetic blends, both the propanoate esters of the stereoisomeric erythro-3,7,11-trimethyltridecan-2-ols originally found in the extract from the female of M. pallipes, surprisingly, showed lower activities in biological studies. Indeed, the propanoates of two threo-isomers gave significantly higher responses in biological tests, than did the propanoates of the two natural erythro-ones. Because the synthetic strategy used earlier was not very efficient for the preparation of the threo-isomers of 3,7,11-trimethyltridecan-2-ol, we were encouraged to look for alternative synthetic approaches. The new synthetic strategy chosen led us to two key synthetic building blocks, an O-protected derivative of (2S,3S)-3-methyl-4-(phenylsulfonyl)butan-2-ol butanol and (3R,7R)-1-iodo-3,7-dimethylnonane. Deprotonation of the former followed by alkylation with the latter should give a compound with the desired carbon skeleton. For efficient preparation of the first building block, we developed a new diastereoselective addition reaction of dialkylzincs to some chiral aldehydes, the products of which were diastereomerically enriched 1,2-dialkyl-alkanols. Using this method, each enantiomer of the desired building block was obtained via efficient diastereoselective addition of dimethylzinc to each enantiomer of a 2-methylaldehyde. The resulting product, a diastereomerically and enantiomerically highly enriched 3-methyl-2-alkanol was further purified by enzyme catalysed acylation followed by some functional group interconversions. The second building block was prepared via convergent multistep synthesis, starting from a single, enantiomerically pure compound, (R)-2-methylsuccinic acid 4-t-butyl ester, derived from the chiral pool. The two enantiomerically pure building blocks, so obtained, were coupled together. Some additional functional group manipulations of the product produced furnished the desired isomer, which had shown the highest activity in field tests of the M. pallipes, namely the propanoate ester of (2S,3R,7R,11R)-3,7,11-trimethyltridecan-2-ol. This thesis describes a number of synthetic approaches for obtaining chiral, enantiomerically pure natural products, in particular some semiochemicals. This has been accomplished by using various strategies; by starting from compounds from the chiral pool, by using chiral auxiliaries, via enzymatic resolutions or by chemical asymmetric synthesis. Hence, the sexual pheromone of Microdiprion pallipes, a propanoate ester of one or several isomers of 3,7,11-trimethyltridecan-2-ol, was synthesised, both as a mixture of all isomers and as the sixteen pure, individual stereoisomers. These compounds were obtained by joining different enantiopure building blocks stemming from the chiral pool. When compared with some synthetic blends, both the propanoate esters of the stereoisomeric erythro-3,7,11-trimethyltridecan-2-ols originally found in the extract from the female of M. pallipes, surprisingly, showed lower activities in biological studies. Indeed, the propanoates of two threo-isomers gave significantly higher responses in biological tests, than did the propanoates of the two natural erythro-ones. Because the synthetic strategy used earlier was not very efficient for the preparation of the threo-isomers of 3,7,11-trimethyltridecan-2-ol, we were encouraged to look for alternative synthetic approaches. The new synthetic strategy chosen led us to two key synthetic building blocks, an O-protected derivative of (2S,3S)-3-methyl-4-(phenylsulfonyl)butan-2-ol butanol and (3R,7R)-1-iodo-3,7-dimethylnonane. Deprotonation of the former followed by alkylation with the latter should give a compound with the desired carbon skeleton. For efficient preparation of the first building block, we developed a new diastereoselective addition reaction of dialkylzincs to some chiral aldehydes, the products of which were diastereomerically enriched 1,2-dialkyl-alkanols. Using this method, each enantiomer of the desired building block was obtained via efficient diastereoselective addition of dimethylzinc to each enantiomer of a 2-methylaldehyde. The resulting product, a diastereomerically and enantiomerically highly enriched 3-methyl-2-alkanol was further purified by enzyme catalysed acylation followed by some functional group interconversions. The second building block was prepared via convergent multistep synthesis, starting from a single, enantiomerically pure compound, (R)-2-methylsuccinic acid 4-t-butyl ester, derived from the chiral pool. The two enantiomerically pure building blocks, so obtained, were coupled together. Some additional functional group manipulations of the product produced furnished the desired isomer, which had shown the highest activity in field tests of the M. pallipes, namely the propanoate ester of (2S,3R,7R,11R)-3,7,11-trimethyltridecan-2-ol.
QC 20101026

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Sebelius, Sara. « Palladium-Catalyzed Synthesis and Transformation of Organoboranes ». Doctoral thesis, Stockholm : Department of Organic Chemistry, Stockholm University, 2006. http://urn.kb.se/resolve?urn=urn:nbn:se:su:diva-1198.

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37

Desai, Bimbisar. « Microwave assisted organic synthesis ». Thesis, University of Surrey, 2002. http://epubs.surrey.ac.uk/842821/.

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The area of chemical research and synthesis increasingly recognises the need for improved technologies and methods, which involves chemical processes with less energy consumption, time savings, reduction and/or minimisation of waste, simple processes and an overall clean production. Microwave heating has been exploited in a variety of disciplines for many useful applications and organic synthesis is an area, which has benefited significantly over the past decade. The present study investigates organic reactions accelerated under microwave irradiations. In particular, the study involves use of recyclable Polymer and Inorganic Solid Supported Reagents for application in transfer hydrogenation. Reductions of electron deficient alkenes have been studied using polymer and inorganic solid supported formates. Microwave irradiations have been used to study transfer hydrogenations in presence of Wilkinson's catalyst [RhCl(PPh3)3]. The application of the Polymer Supported Reagents (PSR) has been investigated for studying transfer hydrogenation in N-benzyl deprotections. Microwave assisted synthesis of formamides from primary and secondary amines have been studied using supported formates. Microwave irradiations have also been applied in studying heterocycle synthesis by cycloaddition of nitrones with Pt (II) and Pd(II) bound organonitriles. The study broadly demonstrates a means of simplifying reaction procedures and purification along with reduction in waste of reagents and release of toxic residues. More importantly, use of microwave irradiations has been used to substantially improve the reaction yields and reduce reaction times, lower energy consumption and solvent volumes. The use of this methodology significantly benefits in the development of "Green Chemistry" and automated systems for chemical synthesis in many industrial sectors.

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Sarkar, Achintya Kumar. « Allylsilanes in organic synthesis ». Thesis, University of Cambridge, 1988. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.292242.

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Hetherington, Peter. « Organic synthesis with bromonitromethane ». Thesis, Queen's University Belfast, 1992. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.317552.

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40

Short, Robert Paul 1951. « Organoboranes in organic synthesis ». Thesis, Massachusetts Institute of Technology, 1989. http://hdl.handle.net/1721.1/14204.

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O'Rourke, Christopher. « Photocatalysis for organic synthesis ». Thesis, Queen's University Belfast, 2014. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.675420.

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A wide range of commercially available self-cleaning materials/products are now available, from architectural materials, such as; glass, paint, plastics, and concrete, to water and air purification systems. These products exploit the destructive oxidative nature of SPC to purify air and water. In contrast, this thesis introduces the less well studied use of SPC to mediate the synthesis of a range of useful organic species, and aims to develop a fast screening process for monitoring such reactions to aid future developments in SPC mediated organic synthesis. It is demonstrated that NMR is a very effective way to monitor SPC mediated organic reactions. By coating the inside of an NMR tube with a sol-gel titania film, and performing SPC reactions in-situ, inside a sealed NMR tube on a 1 mL scale, the need for sample-taking and pre-treatment is negated. The small scale also allows for much faster reaction times. For example, it is shown for the SPC oxidation of toluene, that the use of this NMR/sol-gel titania method is ca. 10 times faster than the more conventional large scale (100 mL) reaction utilising a titania dispersion, whilst still providing similar product yields, thus, demonstrating a new rapid screening method for SPC mediated organic synthesis reactions. Using the new fast screening NMR tube method, the SPC C-C coupling of phenoxyacetic acid (PAA) with N-methylmaleimide (NMI) to produce adduct and cyclic products in yields up to 67% and 15% respectively after only 15 min of UVA irradiation was assessed in detail. Despite the well-known photochemical feature of NMI to form dimers efficiently, the background photochemistry and photocatalysis associated with the individual reactants are shown to be minimal due to the faster SPC kinetics for the coupling reaction. Acrylamide (ACM) was also used in the SPC C-C coupling with PAA, gaving rise to only one product, 4-phenoxybutanamide, in high yields (78%). This efficient reaction was then used to assess the robustness and reusability of the titania coated NMR tubes.

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Wångsell, Fredrik. « Design and Synthesis of Serine and Aspartic Protease Inhibitors ». Licentiate thesis, Linköping University, Linköping University, Organic Chemistry, 2006. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-7372.

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This thesis describes the design and synthesis of compounds that are

intended to inhibit serine and aspartic proteases. The first part of the text deals with preparation of inhibitors of the hepatitis C virus (HCV) NS3 serine protease. Hepatitis C is predominantly a chronic disease that afflicts about 170 million people worldwide. The NS3 protease, encoded by HCV, is essential for replication of the virus and has become one of the main targets when developing drugs to fight HCV. The inhibitors discussed here constitute surrogates for the widely used N-acyl-hydroxyproline isostere designated 4-hydroxy-cyclopentene. The stereochemistry of the 4-hydroxy-cyclopentene scaffold was determined by nuclear overhauser effect spectroscopy (NOESY) and the regiochemistry by heteronuclear multiple bond correlation (HMBC). The scaffold was decorated with different substituents to obtain both linear and macrocyclic HCV NS3 protease inhibitors that display low nanomolar activity. The second part of the thesis describes the design and synthesis of potential aspartic protease inhibitors. The hydroxyethylene motif was used as a noncleavable transition state isostere. The synthetic route yielded a pivotal intermediate with excellent stereochemical control, which was corroborated by NOESY experiments. This intermediate can be diversified with different substituents to furnish novel aspartic protease inhibitors.

Report code: LIU-TEK-LIC-2006:45

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Mitra, Soumya. « Total synthesis of gomisin O asymmetric total syntheses of eupomatilones 1, 2 and 5 ; and studies towards total synthesis of mayolide A / ». Columbus, Ohio : Ohio State University, 2007. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=osu1189449580.

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Nimkar, Sandeep Krishnaji. « Studies in asymmetric synthesis : Development of new synthetic methods for syntheses of natural products ». Diss., The University of Arizona, 1993. http://hdl.handle.net/10150/186538.

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The research, to be discussed in three chapters, involves the development of new synthetic methods which are applicable to the total synthesis of many natural products. Chapter 1: As a part of a program to synthesize new auxiliary agents for asymmetric synthesis, we have prepared a structurally rigid acetal from norbornene in three chemical steps. This enantiomerically pure acetal has been used for resolution of racemic α-hydroxy esters and might be applied as a chiral auxiliary for diastereoselective reactions. Chapter 2: The Calicheamicin and Esperamicin antibiotics have shown remarkable biological activity as site-specific cleaving agents of double stranded DNA. The oligosaccharide portion of these molecules plays an important role in the site specificity. We have developed synthetic methodologies that allow synthesis of the deoxyaminosugar components of these antibiotics and can be extended to synthesize unnatural amino sugars for structure-activity studies. Chapter 3: Enantiomerically pure cyclopropyl ketones, which are available via chiral ketals, are very useful for syntheses and diastereoselective manipulations of common and large rings. This method has been extended to introduce up to four contiguous chiral centers in a common ring. This extension could be useful for the syntheses of complex natural products.

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Pirovano, V. « GOLD-CATALYZED SYNTHESIS AND FUNCTIONALIZATION OF HETEROARENES ». Doctoral thesis, Università degli Studi di Milano, 2014. http://hdl.handle.net/2434/232413.

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This work of thesis describes the results obtained from the study of gold-catalyzed synthesis or functionalization reactions or heteroarenes. The work is presented in four different chapters. The first chapter summarizes the most representative reactivity trends in the field of gold catalysis and serves as general introduction. The second chapter is focused on the cycloaddition reaction of 2-vinylindoles with enones towards the preparation of tetrahydrocarbazole derivatives. This process has been studies using classic Lewis acids and gold complexes as catalysts. According to the results, gold catalysts proved more efficient to accomplish the transformation. In the third chapter, a study on gold-catalyzed cycloaddition reactions of 2-vinylindoles with allene derivatives is presented. This work has allowed to identify two different reaction pathways, a formal 4+2 cycloaddition and a multicomponent reaction, both leading to different tetrahydrocarbazole derivatives. The reaction outcome can be controlled with the judicious choice of the reaction conditions. The forth chapter is devoted to the study of gold- and to less extend silver-catalyzed reactions of indoles with dehydroaminoacis. This study has enabled the discovery of a new reactivity of this substrates. The reaction involves the formation of α-indolylacrilate derivatives.

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Saarinen, Gabrielle. « Development of Synthetic Routes for Preparation of 2,6-Disubstituted Spiro[3.3]heptanes ». Thesis, Mälardalen University, School of Sustainable Development of Society and Technology, 2009. http://urn.kb.se/resolve?urn=urn:nbn:se:mdh:diva-6027.

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2,6-Disubstituted spiro[3.3]heptanes were synthesized to investigate and develop synthetic methods for preparation of these compounds. Possibilities for introducing different functionalities like nitriles and sulfonamides were also investigated.

Synthetic routes presented describe successive [2+2] cycloadditions between dichloroketene and olefins to give the sought after spiro compounds with low to moderate yields throughout the multi-step synthesis. [2+2] Cycloadditions offered low turnovers and chromatography was required for purification.

A synthetic route with cyclisations through double substitution reactions between di-electrophiles and di-nucleophiles resulting in a 2,6-disubstituted spiro[3.3]heptane is also described. This multi-step synthesis offered higher turnover and yields and often there was no need for purification through chromatography.

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Modin, Stefan. « Developments in the Field of Aza-Diels-Alder Reactions, Catalytic Michael Additions and Automated Synthesis ». Doctoral thesis, Uppsala : Acta Universitatis Upsaliensis, Univ.bibl. [distributör], 2004. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-4640.

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Saito, Yu. « Synthesis of bioactive compounds : Synthetic study of D-Lac-terminated peptidoglycan fragment structures ». Thesis, KTH, Kemiteknik, 2021. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-300085.

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Peptidoglycan (PGN) är en bakteriecellväggskomponent och känd för att känna igen olika receptorer eller enzymer för att leda aktiveringsimmunsystemet. Den allmänna strukturen för PGN består av sockerkedjor inklusive N-acetylglutamin (GlcNAc), N-acetylmuraminsyra (MurNAc) och tvärbundna peptidkedjor. PGN-fragment med D-Lac-ändpeptider har hittats från vankomycinresistenta enterokocker men ett kemiskt syntetiserat PGN-fragment med en D-Lac-ändpeptid har inte undersökts i detalj. Således fokuserade vi på syntesen av PGN-fragmentstrukturer som inkluderar en D-Ala-D-Lac-rest vid den terminala delen av peptidkedjan. För att syntetisera dessa fragmentstrukturer planerade vi att kombinera fastfassyntes (för Lac-peptiddelen) och lösningsfassyntes (för glykanberedning och kondensation). Detta tillvägagångssätt är fördelaktigt för framställning av peptidoglykanfragment med en komplex grenad peptiddel. Först beredde vi sockerdelen MurNAc-derivatet i lösningsfassyntes från ett glukosderivat. Medan den Lac-innehållande peptiden framställdes med fastfas-peptidsyntes med användning av 2-klortritylkloridharts. Med denna förening gav kondensationen av dessa två föreningar det önskade D-Lac-avslutade peptidoglykanfragmentet.
Peptidoglycan (PGN) is a bacterial cell wall component and known to be recognized by various receptors or enzymes to lead the activation immune system. The general structure of PGN consists of sugar chains including N-acetylglutamine (GlcNAc), N-acetylmuramic acid (MurNAc) and cross-linked peptide chains. PGN fragments having D-Lac terminus peptides have been found from vancomycin-resistant enterococcus, but a chemically synthesized PGN fragment having a D-Lac terminus peptide has not been examined in detail. Thus, we focused on the synthesis of PGN fragment structures that include a D-Ala-D-Lac residue at the terminal part of the peptide chain. In order to synthesize these fragment structures, we planned to combine solid-phase synthesis (for the peptide- Lac part) and solution-phase synthesis (for glycan preparation and the condensation). This approach is advantageous for the preparation of peptidoglycan fragments having complex branched peptide moiety. First, we prepared the sugar moiety MurNAc derivative in solution-phase synthesis from a glucose derivative. While, the Lac-containing peptide was prepared with solid-phase peptide synthesis using 2-chlorotrityl chloride resin. Having this compound, the condensation of these two compounds gave the desired D-Lac-terminated peptidoglycan fragment.

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Alibhai, Najma. « Part A. The syntheses of dillapiol and its 4-thio derivatives, Part B. The synthesis of trichiliasterone B ». Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1999. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape7/PQDD_0015/MQ48124.pdf.

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50

Mojica, Mike. « Investigation of new synthetic reactions : the synthesis of hydrazines via the Aza-Lossen rearrangement, the synthesis of carbamoyl azides from amines, and deprotection reactions using water at elevated temperatures ». Diss., Georgia Institute of Technology, 2014. http://hdl.handle.net/1853/51791.

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Résumé :

This thesis explores three rare synthetic routes: the synthesis of hydrazines via the aza-Lossen rearrangement, the synthesis of carbamoyl azides from amines, and deprotection reactions using water at elevated temperatures. The aza-Lossen reaction was found to be ideal at “infinite dilution” conditions and could be performed with both aryl and alkyl example. Carbamoyl azides could be synthesized in high yields from both aryl and alkyl amines. The carbamoyl azide reaction was found to be much more efficient with Cs (+1) present. Lastly, water at elevated temperatures conditions was efficient at removing various amine and hydroxyl protecting groups.

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Thèses sur le sujet « Organic Synthessis »

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