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Showing 1 to 20 of 51 for “"dipolar cycloaddition"”.
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Synthesis Towards Fulminic Acid and Its Derivatives in 1, 3-Dipolar Cycloaddition Reactions.
<p>A new approach to fulminic acid cycloadditions has been developed. At reduced temperatures, fulminic acid is generated <em>in situ</em> and undergoes 1, 3-diploar cycloaddition reactions with dipolarophiles to form isoxazolines and/or its dimers. This procedure represents a novel, safe general …
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Bioorthogonal Reactions: Synthesis and Evaluation of Different Ligands in Copper Catalyzed Azide-Alkyne1,3-Dipolar Cycloaddition (CuAAC)
<p>The Copper CatalyzedAzide-Alkyne1,3-Dipolar Cycloaddition (CuAAC) reaction has unique features that qualify it to be one of the best click reactions. Its applications have been shown in different aspects and for multiple purposes. The oxidative degradation of biological systems (labile proteins …
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Damaged Collagen Detection and A Novel Approach to 1,3-Dipolar Cycloaddition Reactivity: Research at the Interface of Chemistry and Biology
… Part II Chapter 1. Acceleration of 1,3-Dipolar Cycloadditions by Integration of Strain and Electronic-Tuning. The 1,3-dipolar cycloaddition between azides and alkynes is enabling new means to probe and control biological processes. A major challenge is to achieve high reaction rates with …
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Interfacial Nitrone 1,3-Dipolar Cycloadditions for Modification of Monolayer Protected Gold Nanoparticles
… as a template and its ability to undergo the 1,3-dipolar cycloaddition reaction with a series of nitrones under ambient and high-pressure conditions. Expanding the scope of this reaction to the investigation in synthesizing a nitrone modified-MPN and examine its ability to undergo the 1,3-dipolar …
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Enantioenriched Homoaldol Products, Beta-Substituted Ketones, Isoxazolines, and Beta-Lactams Through Elaboration of Allylamine Asymmetric Homoenolate Equivalents: Synthesis and Elucidation of Reaction Pathways
A stereocontrolled intramolecular nitrone/olefin dipolar cycloaddition reaction of enantioenriched enals provides cyclopentyl isoxazoline products in 64--81% yields and with diastereomeric ratios of 78:22 to 84:16. An isoxazoline was converted into an enantiomerically pure beta-lactam via a …
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Cross-Linked Polybenzyl Ether and Polyglycerol Dendrimers for Monomolecular Imprinting
… alkyne groups using copper-catalyzed 1,3-dipolar cycloaddition. The glycoside dendrimers displayed chiral activity that increased after the dendrimers were cross-linked. However, after core removal the dendrimers were optically inactive.
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Synthesis of Delta(3)-Imidazolines as Latent Forms of Peptidyl Trifluoromethyl Ketones
… amino acid fluorides as the initiator of the dipolar cycloaddition. The imidazolines then functioned as a protecting group for the trifluoromethyl ketones during typical peptide Fmoc deprotection and elongation reactions. In the final step, the imidazoline was hydrolyzed with dilute acid, …
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Efforts Toward the Total Synthesis of Asparagamine A
… utilizes an intramolecular azomethine ylide 1,3-dipolar cycloaddition reaction as the key step. Generation of the azomethine ylide species is achieved via sequential vinylogous amide O-sulfonylation and desilylation. Several strategies designed to construct the fully oxygenated …
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Asymmetric Total Synthesis of (+)-Nominine: Development of a Dual Cycloaddition Strategy for the Synthesis of the Hetisine Alkaloids
A dual cycloaddition strategy for the synthesis of the hetisine alkaloids has been developed and applied to the asymmetric total synthesis of nominine. The approach relies on an early stage intramolecular aza-1,3-dipolar cycloaddition of a 4-oxidoisoquinolinium betaine with an ene-nitrile …
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ΜΕΛΕΤΗ ΑΝΤΙΔΡΑΣΕΩΝ ΠΡΟΣΘΗΚΗΣ ΠΥΡΑΖΟΛΙΚΩΝ ΣΥΣΤΗΜΑΤΩΝ ΜΕ 1, 3-ΔΙΠΟΛΑ ΚΑΙ ΚΕΤΕΝΕΣ
… AND NITRILIMINES UNDERGO STEREOSELECTIVELY 1,3-DIPOLAR CYCLOADDITION, IN PRESENCE OF DIPHENYLNETENE THE CORRESPONDING 1-DIPHENYL-ACETYL (3,3-DIPHENYL- 2-AROGLOXY-2-PROPENYYL)-4,4 DIMETHYL-S-METHYLENE-1H PYRAZOLES. AROMATIC TRIMETHYL-PYRAZOLES IN PRESENCE OF NITRILOXIDES UNDERGO AN ELECTROPHILIC …
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Efforts Toward the Total Synthesis of the Original and Revised Structures of Palau'amine
… utilizing an intramolecular azide [3+2]-dipolar cycloaddition. Also of note is the development of new methods for the preparation of the polycyclic pyrazinones. Application of this cyclization strategy has allowed for synthesis of the advanced intermediates possessing the fully …
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Lewis acid catalysis in organic synthesis
… catalytic system has been developed for 1,3-dipolar cycloaddition of azides to terminal alkynes using CuCl-RTIL. This catalytical system gives only 1,4-disubstituted 1,2,3-triazoles. Reactions of Alkyl and aryl azides with a variety of terminal alkynes were successfully catalyzed using …
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Neue heterocyclische Sulfoximine
… and were used as substrates in Huisgen-1,3-dipolar cycloaddition reactions with organic azides. The corresponding sulfoximidoyl-1,2,3-triazoles were obtained in yields up to 73%. The regioselectivities were examined by use of 1H-NOESY-spectroscopy. It became apparent that only …
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The progress towards the total synthesis of (ent)-MPC1001
… with the development of a novel asymmetric [1-3]-dipolar cycloaddition utilizing a vinyl silane and a chiral lactone template. The mechanism of the cycloaddition was investigated and the cyclized product can be elaborated in 6 steps to the A-B-C ring system of the MPC family of natural products. …
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Kinetics of Polymer Interfacial Reactions
… 5-chloro-pentyne to form triazoles via a 1,3-dipolar cycloaddition reaction. Time-resolved ATR-IR measurements indicate that the interfacial click reaction is initially first order in azide concentration, and then transitions to apparent second order dependence, when the surface azide and …
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APPLY LADDER OF CHEMICAL CIRCULARITY: RECYCLING OF RARE EARTH ELEMENTS RECOVERED FROM ELETRONIC WASTE AS A CATALYST IN ORGANIC REACTION.
… and selectivity. Additionally, a Diels-Alder cycloaddition was performed using chiral auxiliaries, promising results in terms of both reaction yield and enantioselectivity. The thesis also explores sustainable catalytic approaches by testing reactions using fluorescent lamps recovered from …
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Synthesis and evaluation of polystyrene based soluble polymeric supports for organic synthesis
… The target compounds were synthesized via 1,3-dipolar cycloaddition reactions between polymer bound alkenes and nitrile oxides generated in situ from their corresponding aldoximes. The cleaved ?2-isoxazoline compounds were tested for biological activity against Mycobacterium fortuitum. To …
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Total Synthesis of Apratoxin A Analogues
… The azide has been successfully used in a 1,3-dipolar cycloaddition with a biotinylated alkyne, which will be assayed to help determine the molecular targets of apratoxin A. Furthermore, the polyethylene glycol azide provides us with a handle to install additional biological tags.
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Synthesis and Properties of Chemically Modified Carbon Nanotubes
… using pyridine diazonium salt addition, 1,3-dipolar cycloaddition and reductive alkylation. The selectivitiy of the addition was probed by UV-vis-NIR and Raman spectroscopy where the metallic were found to be more selective than semiconducting SWNTs. The location and distribution of the …
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From the Making to the Tuning to the Use of Chlorins for Biomedical Applications
… free base of a pyrrolidine ring form from a 1,3-dipolar cycloaddition. This strategy allows rapid conjugation to biological and biotargeting motifs. As a demonstration, the soluble chlorin platforms were conjugated to lysozyme and to an amino terminated tether on a short oligonucleotide. These …
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