|
|
Thermochemical Properties of High Nitrogen Energetic Materials
Bartošková, Monika ; Munzarová, Markéta (referee) ; Potáček, Milan (referee) ; Jalový,, Zdeněk (referee) ; Vávrová, Milada (advisor)
The main goal of the presented thesis is a theoretical study of heat of formation for high-nitrogen energetic materials. A modification of the classical approach to the isodesmic reactions is realized with the intent that molecules on both sides of the corresponding equation have not only the same number of atoms but also approximately the same size and skeletal similarity. This approach is designated as a method "Alternative Isodesmic Reaction (AIR method)". At its base, using the DFT B3LYP / cc-pVTZ and B3PW91 / cc-pVTZ, for the high nitrogen heterocycles, which are selected from the group of triazoles, triazines, tetrazines, the enthalpy of formation values the gaseous phase f H°(298,g), were obtained whose values are close to the published f H°(298,g). Their application in the calculation of the relevant characteristics of these heterocycles detonation gave real values.
|
|
|
Synthesis and properties evaluation attempts in new highermolecular conjugated systems applied for optoelectronics.
Skrášek, Martin ; Repková, Martina (referee) ; Potáček, Milan (advisor)
The aim of this project was a literature search on application of organic semiconductors in optoelectronics and on synthesis of higher molecular conjugated precursors containing C=N bonds. Project is divided into theoretical section, experimental section and discussion. Theoretical part is focused on conductivity in organic compounds, principle of absorption and emission of energy radiation and its application in organic light-emitting diodes. There are also described reactions, which can be used for syntheses of target substances. Subject of the experimental section is synthesis of planned structures and their structure characterization. In the discussion part detailed description of the used methods is presented, problems with their application and final results.
|
|
|
Heterocyclic Compounds with Antimycobacterial Activity
Herzigová, Petra ; Klimešová, Věra (advisor) ; Potáček, Milan (referee) ; Pytela, Oldřich (referee)
The dissertation thesis belongs to the conception of the research of potential antimycobacterial compounds. The aim of this work is synthesis of sulphide pyridine derivatives and the relationship between structure and antimycobacterial activity. Within the framework of this Thesis, the 112 substituted derivates of 4-(subst. fenylalkylsulfanyl)pyridine-2-carboxylic acid were synthesized. Antimycobacterial activity of prepared substances has been tested under in vitro conditions against M. tuberculosis, and non-tuberculous mycobacteria M. avium and M. kansasii. The series of 4-(subst. phenethylsulfanyl)pyridine-2-carbothioamide (MIC 1-32 µmol/L) represents the most active substances (MIC 1-32 µmol/L). These derivates don't reach the activity used antituberculosis drugs against M. tuberculosis, but their activities against M. avium exceed that of isoniazid. The synthesis of new structures as potential antimycobacterial compounds forms the second part of Thesis. All synthesis is based on the use of bis- arylimidoyl chlorides of oxalic acid of as starting material. None of prepared new compounds don't display an interesting antimycobacterial activity.
|
|
| |
|
|
Preparation of enantiomerically pure cyclic compounds via organocatalytic concept
Remeš, Marek ; Veselý, Jan (advisor) ; Potáček, Milan (referee) ; Cibulka, Radek (referee)
Since 2000 the organocatalytic synthesis has developed massively in a third pillar of asymmetric synthesis standing next to catalysis with metal complexes and enzymatic catalysis. Organocatalysts, due to their various activation modes which could be combined in domino reactions, offer a way for a synthesis of complex molecules from a simple starting material. This thesis deals with investigation of usage of chiral secondary amines as catalysts for asymmetric synthesis of cyclic compounds. The main part of research was devoted to development of organocatalytic method leading to synthesis of enantiomerically pure cyclopentanecarbaldehydes and nitrocyclopentanecarbaldehydes. We focused also on the organocatalytic preparation of cyclohexanecarbaldehydes. During this work we developed an asymmetric domino Michael addition/α- substitution reaction of 2-(2-bromoethyl)malonates resp. 1-bromo-3-nitropropane with various enals catalyzed by chiral secondary amine. In the first case cyclopentanecarbaldehydes were formed where two chiral centres were created. In second case nitrocyclopentanecarbaldehydes were formed where three chiral centres were created. Yields of such developed reaction protocol reach up to 74 % and the reaction proceeds with excellent diastereo- and enantioselectivity (up to 19:1 d.r. and...
|
|
|
Modular synthesis of N-heteroaromatic cations by (2+2+2) cycloaddition
Čížková, Martina ; Teplý, Filip (advisor) ; Kotora, Martin (referee) ; Potáček, Milan (referee)
5 Abstract N-Heteroaromatic cations represent a family of compounds with diverse application potentials including natural products, DNA probes, fluorescence dyes, herbicides, ionic liquids, organocatalysts, etc. The preparation of these species proceeds mainly through N-alkylation which is used mostly as a last step of the synthetic sequence. Only limited diversity of cationic substrates can be achieved with this manner, hence, searching for other methods leading to novel Nheteroaromatic cations is of great interest. Some examples of transition metal-catalyzed transformations on organic cations have appeared over the last two decades including Suzuki- Miyaura reaction, Sonogashira and Stille coupling, oxidative homocoupling, ring-closing metathesis, etc. Here, the successful construction of new N-heteroaromatic cations by [2+2+2] cycloaddition is presented. A methodology for the synthesis of novel pyridine-type organic monocations was developed using gaseous acetylene as a reaction partner in the cyclization step. Subsequently, the double [2+2+2] cycloaddition was utilized for the preparation of oligo-p-phenylenes with two to seven para connected phenylene units. Furthermore, the intramolecular version of the cyclization step led to two helical and four linear dications which can be considered as extended...
|
|
|
Synthesis and Functionalization of 5-Substituted Tetrazoles
Roh, Jaroslav ; Hrabálek, Alexandr (advisor) ; Potáček, Milan (referee) ; Csöllei, Jozef (referee)
In the last decades, the chemistry of tetrazoles underwent a great expansion, which was closely connected with their usage as an isosteric replacement of carboxylic acid moiety in the molecules of potential or clinically used drugs. In this work, existing methods of the preparation of 5-substituted tetrazoles were modified by utilising microwave irradiation and by changing the reaction conditions and the reaction medium. First, Sharpless synthesis, consisting in the conversion of nitriles into 5-substituted tetrazoles via the reaction of sodium azide and zinc halide in boiling water, was modified. The application of the microwave irradiation decreased reaction time while maintaining high yields of products. Furthermore, a new method for the preparation of 5-substituted tetrazoles was developed, based on the reaction of nitrile with sodium azide and triethylammonium chloride in the polar aromatic solvents under microwave irradiation. By this method, 5-substituted tetrazoles were prepared in high yields in short reaction times from nitriles, including those that react poorly using common methods. Based on the results of several selected methods of the preparation of 5-substituted tetrazoles, carried out under either conventional or microwave heating at the same reaction temperatures, the non-thermal...
|
|
|
Chemical constituents of stems and leaves of Vaccinium myrtillus
Hybelbauerová, Simona ; Koutek, Bohumír (advisor) ; Klinot, Jiří (referee) ; Potáček, Milan (referee) ; Šmidrkal, Jan (referee)
1. Introduction The study of natural compounds is a tÍaditional part of organic chemistry with rich history. The development of the isolation methods like chromatography and spectral methods enables studying of these compounds in viable organisms more in detail. The new techniques for very fast assesment ofbiological activity allow targeted searching for biological active compounds. The extract from plants is only roughly sepaÍated and the biological activity is meassured often against many viruses, microorganisms and types of cancer. The fractions with interesting results are searched further until the compounds responsible for the biological activity are found. Because of the high content of anthocyanines and flavonoids in fruits of Vaccinium myrtillus, there is a big interest in the study ofthese compounds and study of their effect on human health. The extracts not only from the fruits but also from the leaves are part of folk medicine and classic health care in treatment of the inflammatory diseases. The biological activity ofthe extracts is caused not only by flavonoids but also by isoprenoid compounds such as oleanolic acid, which is often talked about without any scientific proof. Publications involving natural compounds are usually only about one type of compounds - anthocyanines, flavonoids,...
|
|
|
Heterocyclic Compounds with Antimycobacterial Activity
Herzigová, Petra ; Klimešová, Věra (advisor) ; Potáček, Milan (referee) ; Pytela, Oldřich (referee)
The dissertation thesis belongs to the conception of the research of potential antimycobacterial compounds. The aim of this work is synthesis of sulphide pyridine derivatives and the relationship between structure and antimycobacterial activity. Within the framework of this Thesis, the 112 substituted derivates of 4-(subst. fenylalkylsulfanyl)pyridine-2-carboxylic acid were synthesized. Antimycobacterial activity of prepared substances has been tested under in vitro conditions against M. tuberculosis, and non-tuberculous mycobacteria M. avium and M. kansasii. The series of 4-(subst. phenethylsulfanyl)pyridine-2-carbothioamide (MIC 1-32 µmol/L) represents the most active substances (MIC 1-32 µmol/L). These derivates don't reach the activity used antituberculosis drugs against M. tuberculosis, but their activities against M. avium exceed that of isoniazid. The synthesis of new structures as potential antimycobacterial compounds forms the second part of Thesis. All synthesis is based on the use of bis- arylimidoyl chlorides of oxalic acid of as starting material. None of prepared new compounds don't display an interesting antimycobacterial activity.
|
|
|
Thermochemical Properties of High Nitrogen Energetic Materials
Bartošková, Monika ; Munzarová, Markéta (referee) ; Potáček, Milan (referee) ; Jalový,, Zdeněk (referee) ; Vávrová, Milada (advisor)
The main goal of the presented thesis is a theoretical study of heat of formation for high-nitrogen energetic materials. A modification of the classical approach to the isodesmic reactions is realized with the intent that molecules on both sides of the corresponding equation have not only the same number of atoms but also approximately the same size and skeletal similarity. This approach is designated as a method "Alternative Isodesmic Reaction (AIR method)". At its base, using the DFT B3LYP / cc-pVTZ and B3PW91 / cc-pVTZ, for the high nitrogen heterocycles, which are selected from the group of triazoles, triazines, tetrazines, the enthalpy of formation values the gaseous phase f H°(298,g), were obtained whose values are close to the published f H°(298,g). Their application in the calculation of the relevant characteristics of these heterocycles detonation gave real values.
|
guest ::
