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Application of amines for the preparation of chiral cyclic compounds
Formánek, Bedřich ; Veselý, Jan (advisor) ; Kočovský, Pavel (referee) ; Soural, Miroslav (referee)
Organocatalysis, along with catalysis by metal complexes or enzymes, has become one of the very useful tools of asymmetric synthesis. Different activation modes or their combinations into sequences (domino reactions) enable effective access to enantiomerically enriched complex substances. The objective of this work was the preparation of chiral molecules from simple precursors activated by amine-based organocatalysts. In particular, we were focused on a study of asymmetric allyl substitution of Morita-Baylis-Hillman carbonates and two-component domino reactions on sulfur-containing heterocycles. The thesis deals with the organocatalytic allyl amination of Morita-Baylis-Hillman carbonates with aromatic amines catalyzed by β-isocupreidine. The corresponding allylic amines were obtained in high yields (90-96%) with moderate enantiomeric excess. It was possible to get substances of high optical purity (ee 82-99%) by recrystallization of selected products. Furthermore, the developed method was applied in the preparation of enantiomerically enriched β-lactams, which represent valuable precursors, for example, in the synthesis of the drug Ezetimibe. The second part of the work is focused on stereoselective cyclization reactions comprising selected sulfur heterocycles. Although the cyclization reaction of...
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Transparent polycrystalline ceramics at visible and infrared wavelenghts
Veselý, Jan ; Maca, Karel (referee) ; Trunec, Martin (advisor)
his thesis deals with preparation of transparent ceramic sheets made out of sub-µm alumina powder. Green bodies are prepared by ultraviolet (UV) curing of UV curable resin containing ceramic powder followed by debinding of organic parts at elevated temperature. High relative density of green bodies is essential for reduction of shrinkage during subsequent sintering process. Therefore high solids loading dispersions containing > 57 vol% ceramic particles are used. To reach transparent behaviour, porosity within the sheets must be reduced completely. Therefore hot isostatic pressing (HIP) is used as a final operation. Finally, light transmission and hardness measurements are presented. Possibilities of making high resolution microstructures using maskless lithography and some suggestions for use of the UV curing technique for production of complex-shaped 3D structures are briefly mentioned.
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Gelcasting of Advanced Ceramics
Veselý, Jan ; Maca, Karel (referee) ; Trunec, Martin (advisor)
In Bachelor thesis, a literary overview of gelcasting method was worked out and pursuant to this overview, composition of alumina suspension was optimised for fabrication of bulky and complex-shape ceramic part. Four variants of ceramic powder filling in suspensions were prepared. Based on the experiments, a suspension with powder loading of 47,5 vol. % was chosen. The ratio between linear and crosslinking monomers was investigated for this suspension. A suspension with monomer ratio of 4 : 1 (linear : crosslinking) was chosen for preparation of bulky and complex-shape ceramic part. Gelcasting was verified by fabrication of ceramic medal and a knee-joint.
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N-heterocyclic carbene catalysis in enantioselective cycloadditions
Krejčířová, Kateřina ; Veselý, Jan (advisor) ; Baszczyňski, Ondřej (referee)
This diploma thesis deals with selected enantioselective cycloaddition reactions catalyzed by N-heterocyclic carbenes. First, we focused on studying the [4+3] cycloaddition reaction. Non-commercial ketimines were prepared as starting materials for the model reaction. Subsequently, the reaction between ketimines and salicylaldehyde was studied, where, despite all efforts, preparing the desired product was impossible. Furthermore, the [3+3] cyclization reaction was studied. Aminopyrazole and substituted α-bromenals were prepared for these purposes. However, while optimizing this reaction, the same concept was published. Finally, our attention was focused on the [3+2] cycloaddition reaction between α-bromenals and hydrazides derived from oxalic acid esters. Here, the reaction conditions were optimized, and the substrate scope was subsequently studied.
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Synthesis of phosphono-bis(phosphinate) cyclam derivative
Chrappa, Michal ; Hermann, Petr (advisor) ; Veselý, Jan (referee)
Radiopharmaceuticals containing copper isotopes can be used as diagnostic tools (methods PET, SPECT) or agents for tumour treatment. Copper radionuclides must be applied into the organism in the form of a coordination compound with suitable ligand. Derivatives of 1,4,8,11-tetraazacyclotetradecane (cyclam) are some of the most suitable ligands for Cu (II). A coordination compound must be thermodynamically stable and kinetically inert, the ligand must coordinate the metal ion as quickly as possible. In this Diploma thesis, one of the first unsymmetrically substituted derivatives of cyclam has been synthesized using two methods of orthogonal protection. The synthesized ligand contains one phosphonate and one methylene bis(phosphinate) pendant arm. Copper complex of the ligand was prepared, and its acid assisted dissociation kinetics were studied.
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The Poetics of the British Sitcom
VESELÝ, Jan
This master's thesis is focused on British sitcoms, which represent one of the basic elements of British humour as a much sought-after phenomenon across the world, including the Czech Republic. The thesis aims to introduce the reader to this particular television genre and outline the elements of comedic content both in general, as well as in relation to certain selected works. The thesis also aims to demonstrate how the described phenomenon transcends the usual framework of television. Regarding the methodology for examining the subject matter, a synthesis of relevant sources as well as various insights obtained during the master's studies are used to examine certain selected works of popular culture which represent the very essence of British sitcoms. The thesis outlines the boundaries of a television sitcom as an independent genre, also focusing on comedic works preceding the sitcom, overlaps with other genres and various specifics connected to the British cultural environment. Established macro theories of humour are applied to the British sitcom in order to explain the source of the comedic effect, as well as the influence of comedy in relation to relieving tension within society. The thesis focuses in particular on careful observations of the humour in certain cult works of comedy, such as Yes, Minister/Yes, Prime Minister, 'Allo 'Allo!, Red Dwarf and The IT Crowd. The closest attention is paid to the role of the individual characters and environments in selected sitcoms, since those elements might be considered vital for a successful sitcom. The influences of British productions in this area as a whole are also mentioned, noting the social relevance of this often-overlooked phenomenon.
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Development of catalytic systems suitable for the enantioselective synthesis of heterocycles
Dočekal, Vojtěch ; Veselý, Jan (advisor) ; Cibulka, Radek (referee) ; Pospíšil, Jiří (referee)
The development of novel methodologies and synthetic strategies for the preparation of complex 3D heterocyclic compounds with the well-defined spatial arrangement of functional groups represents one of the most studied research problems in current synthetic chemistry. Nowadays, organocatalysis (beside transition-metal catalysis and biocatalysis) became the most popular tool, because of usage small chiral organic compound for asymmetric induction and acceleration of reaction. In this thesis, the development of novel organocatalytic methodologies for the preparation of various heterocyclic compounds is described. The utility of novel methodologies is demonstrated by easy access to chiral building block molecules or products with valuable physical or biological properties. In the first part, a novel [4+2] cycloaddition reaction of sulfur-containing heterocyclic electron-deficient alkenes with allenic compounds catalyzed by chiral tertiary amine is described. Organocatalytic cycloaddition reaction of 3-benzylidene benzo[b]thiophenones with allenoates was investigated and optimized. Dihydro-2H-pyranes were obtained in high isolated yields (up to 92%) and optical purities (up to 99% ee). The robustness and synthetic utility of the developed methodology was demonstrated by a simple work-up of...
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Preparation of chiral amides and their use as organocatalysts
Brandejsová, Aneta ; Veselý, Jan (advisor) ; Hrdina, Radim (referee)
This bachelor thesis is focused on preparation of C-9 amino derivatives of Cinchona alkaloids and derived bifunctional squaramide catalysts, which are used as organocatalysts in a wide variety of chemical transformations leading to enantiomerically pure compounds. The first part deals with choosing the most efficient method for the preparation of C-9 amino derivates of Cinchona alkaloids and the synthesis of four selected examples. In the second part, the prepared derivates are used for the synthesis of bifunctional squaramide catalysts, which are further tested in newly designed cyclization reactions.
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