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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Syntéza a vlastnosti monosubstituovaných derivatů cyklodextrinů / Synthesis and properties of monosubstituted derivatives of cyclodextrins

Řezanka, Michal January 2012 (has links)
This Ph.D. thesis deals with synthesis of monosubstituted cyclodextrin derivatives and investigating their properties. Alkylation of -cyclodextrin with allyl or cinnamyl bromide followed by peracetylation of remaining hydroxyl groups and separation of isomers resulted in the set of peracetylated 2I - O-, 3I -O- and 6I -O-alkylated cyclodextrins in up to 27% yields. Oxidative cleaveage of peracetylated allyl or cinnamyl derivatives resulted in a complete set of peracetylated 2I -O-, 3I -O- and 6I -O- formylmethyl or carboxymethyl derivatives which are useful precursors for preparation of regioselectively monosubstituted derivatives of -cyclodextrin. Moreover, a quick method to recognize single 2I -O-, 3I -O- and 6I -O- monosubstituted peracetylated cyclodextrins from each other using only 1 H NMR spectrum has been proposed. Ru-carbene complex catalyzed cross-metathesis of monoallyl -, -, and -cyclodextrins with perfluoroalkylpropenes resulted in the formation of the corresponding perfluoroalkylated cyclodextrins. The reactions proceeded under standard reaction conditions and the desired compounds were obtained in reasonable yields. Dynamic light scattering measurements proved the ability of the prepared compounds to aggregate in water solution forming nanoparticles in the range of tens and...
2

Potenciál cholesterolem obalených cyklodextrinů a nízkodenzitního lipoproteinu pro zvýšení účinnosti kryokonzervace epididymálních spermií hřebců / Potential of cholesterol-loaded cyclodextrins and low density lipoprotein for increasing the efficiency of cryopreservation of epididymal sperms in stallions

Janošíková, Martina January 2016 (has links)
In the case of sudden death or injury stallion reproductive system or necessary castration preventing the collection of semen can to preserve the genetic potential of exceptional individuals take advantage of epididymal sperm. Virtually the only way, how to preserve fertilizing sperm POTENTIAL for long time IS cryopreservation. However, this process induces irreversible changes that are the cause of the reduced number of sperm capable of fertilization after thawing. Epididymal sperm cells have properties different from the ejaculated, harder to keep. Therefore, they are constantly looking for ways to streamline their cryopreservation. GENERAL most commonly used cryoprotectants include glycerol and Egg yolk. Despite the positive effects is glycerol toxic to cells and Egg yolk also contains ingredients that act on sperm metabolism negatively. Increasing the efficiency of cryopreservation protocols themselves likely to be achieved by replacing toxic components while leveraging industry-produced active yolk fractions. Submitted dissertation topic itself will deal with the use of cholesterol-loaded cyclodextrins Along with low density lipoproteins, the cryopreservation of epididymal sperm. Main method: HPLC, Western blot, electrophoresis, fluorescent labels, computer-assisted sperm analysis (CASA).
3

Användning av cyklodextrinerför att öka läkemedels löslighet : En litteraturstudie om hur lösligheten hos naproxen kan påverkas av cyklodextriner

Frostlynx Pollack, Honey January 2017 (has links)
No description available.
4

Syntéza cyklodextrinových derivátů za využití methoxymethylových chránících skupin / Synthesis of cyclodextrin derivatives using methoxymethyl protecting groups

Kasal, Petr January 2015 (has links)
This work deals with the use of methoxymethyl protecting group in chemistry of cyclodextrins, where this group has not been used very often so far. The work deals with development of optimal methods for introduction and for subsequent removal of the group and shows its usefulness in the preparation of new 6I -O-monosubstituted cyclodextrin derivatives, which are hard to get by standard methods. Key words: cyclodextrin derivatives, methoxymethyl group, protecting group
5

Příprava derivátů cyklodextrinů použitelných pro modifikace pevných povrchů / Preparation of cyclodextrin derivatives usable for modifications of solid surfaces

Bednářová, Eva January 2014 (has links)
This master thesis deals with preparation of cyclodextrin (CD) derivatives that are suitable for bonding on solid surfaces such as dopamine polymer and gold. The nucleophilic attack of 6I -O-p-toluenesulfonyl--CD (6-tosyl-β-CD) by dithiols created derivatives with substituents bound to CD skeleton by one of the sulphur atom while keeping a free terminal sulphanyl group. Despite initial problems caused by oxidation of the thiols to disulfides, CDs were modified by alkyl or oligoethylene glycol spacers prepared in 60 - 88% yields. The same reaction was used for preparation of derivatives of β-CD with amino group at the end of the tether that was linked to CD by nitrogen atom. For these purposes were used corresponding diamines and reactions proceeded smoothly reaching up to 92% isolated yield. Next, also the chemoselectivity of the reaction with an ambident spacer bearing both amino and sulphanyl functional group was studied and by 2D NMR experiments was proved that substituent was bound to CD through sulphur atom. It was demonstrated on the case of preparation of CD derivative with dimethylene linker that was prepared in 84% yield. A complete set of yet other CD-oligoethylene glycol derivatives with spacers linked to CD skeleton through the sulphur atom and terminated by amino group was prepared by...
6

Příprava derivátů γ-cyklodextrinu použitelných pro tvorbu samoskladných struktur / Preparation of γ-cyclodextrin derivatives usable for construction of self-assembled structures

Bláhová, Markéta January 2014 (has links)
This thesis is focused on the preparation of monosubstituted derivatives of -cyclodextrin ( -CD) which can form supramolecular polymers. These polymers can be utilized in capillary electrophoresis. Set of monosubstituted 2I -O-, 3I -O- a 6I -O-(3-(naphthalen-2-yl)prop-2-en-1-yl) derivatives of -CD was prepared (naphthylallyl derivatives). Reaction was performed by cross metathesis of O-allyl derivatives of -CD with a 2-vinylnaphthalene in yields 16 - 25 %. Hoveyda-Grubbs 2nd generation catalyst was used. Alkylation of -CD with 2-(3-bromoprop-1-enyl)naphthalene followed by peracetylation of remaining hydroxyl groups and separation of isomers resulted in the per-O-acetyl-3I -O- a per-O- acetyl-6I -O-(3-(naphthalen-2-yl)prop-2-en-1-yl)- -CD in yields 5 and 1 %. A set of dimers of -CD 1,4-bis( -CD-2I -O-yl)-but-2-ene, 1,4-bis( -CD-3I -O-yl)-but-2-ene and 1,4-bis( - CD-6I -O-yl)-but-2-ene was prepared, too. Reaction was performed by cross metathesis of O-allyl derivatives of -CD in yields 1 - 8 % using again Hoveyda-Grubbs 2nd generation catalyst. The dimers of naphthalene guests (1,2-bis(naphthalen-2-yl)ethene and 1,2-bis(naphthalen-2-yl)ethane) for preparation of complexes with CD dimers were also prepared. Further optimization of synthesis of naphthylallyl derivatives of -CD was carried out. These...
7

Příprava mono-aryl-per-6-(methylsulfanyl) derivátů beta-cyklodextrinu použitelných jako selektory pro detekci uhlovodíků / Preparation of mono-aryl-per-6-(methylsulfanyl) derivatives of beta-cyclodextrin usable as selectors for detection of hydrocarbons

Zima, Václav January 2015 (has links)
This master thesis deals with the preparation of β-cyclodextrin derivatives which can be attached on gold surface via methylsulfanyl groups. The thesis particularly deals with the preparation and characterization of mono-aryl-per-6-(methylsulfanyl) derivatives of β-cyclodextrin prepared from corresponding monopropragyl derivative. This work also deals with the attachment of per-6-deoxy-per-6-methylsulfanyl-β- cyclodextrin to gold surface of quartz crystal microbalances. Keywords: β-cyclodextrin, methylsulfanyl derivatives, propargyl derivatives, cyclodextrin derivatization, click reaction
8

Příprava benzoylovaných derivátů cyklodextrinů / Preparation of benzoylated derivatives of cyclodextrins

Jůza, Radomír January 2017 (has links)
This master thesis deals with the preparation of the cyclodextrin (CD) derivatives that are suitable for complexation of the electron-rich aromatic compounds such as helicenes. The basic skeleton of native CD was perbenzoylated in all positions 2, 3 and 6 in the first place. Then the nucleophilic attack of carboxylates of benzoic acids with electron- withdrawing groups (NO2) or electron-donating group (NH2) to per(6-deoxy-6-iodo)-CD derivatives were used to prepare the perbenzoylated CD derivatives in the postition 6. Binding constant was determined for the prepared benzoylated derivatives of CD and the racemate of the hexahelicene using the NMR titration. Perbenzoylated derivatives of β-CD in all position 2,3 and 6 with one azido group in position 6 were prepared as well. These derivatives could be covalently bonded as chiral selectors in the stationary phase for the HPLC separation of aromatic enantiomers. Keywords: cylodextrins, persubstitution, benzoyl, 4-nitrobenzoyl, 3,5-dinitrobenzoyl, helicenes, NMR titration, binding constants
9

Konjugáty cyklodextrin-léčivo vybavené targetujícími skupinami jako protinádorová agens / Cyclodextrin-drug conjugates equipped with targeting groups as anticancer agents

Lamačová, Lucie Josefa January 2021 (has links)
This diploma thesis deals with the synthesis of conjugates of cyclodextrin with the anticancer drug 5-fluorouracil and folic acid, which works as a targeting group. 5-Fluorouracil is connected to cyclodextrin via an acid-labile linker, which is expected to be cleaved in decreased pH in the proximity of malignant tissue or in the endosome. Malignant tissue also overexpresses receptor for folic acid, and this phenomenon is used for targeted delivery of therapeutic agents. Cyclodextrins are cyclic oligosaccharides, which are known for their ability to complex various compounds into their hydrophobic cavity and increase solubility, stability and bioavailability of these compounds. A synthetic approach for the preparation of conjugate of cyclodextrin with 5-fluorouracil and folic acid was designed and the conjugate was subsequently synthesized. Key words: cyclodextrin, fluorouracil, targeting group, folic acid, drug delivery
10

Sulfobutylether-β-cyklodextrin jako chirální selektor pro separace aminokyselin a dipeptidů v HPLC / Sulfobutylether-β-cyclodextrin as a chiral selector for separation of amino acids and dipeptides in HPLC

Procházková, Hana January 2017 (has links)
The main aim of this work was to prepare and characterize a new chiral stationary phase (CSP). The CSP was prepared by dynamic coating of sulfobutylether- β-cyclodextrin (SBE-β-CD) on a strong anion-exchange stationary phase (SP). The selectivity and stability of the newly prepared CSP were tested on the sets of chiral and achiral analytes. The next separation system used was composed of C18 SP with the addition of SBE-β-CD as a chiral selector into the mobile phase. The set of chiral analytes contained amino acids phenylalanin, tyrosine, tryptophan, their derivatives and dipeptides glycine-DL-tryptophan and glycine-DL- phenylalanin. Four groups of mixtures of blocked and unblocked dipeptide isomers were tested for achiral separations. Dipeptides used for the mixtures had the same molecular formula but the sequence of amino acids was reversed. Measurements were carried out in reversed phase separation mode and hydrophilic interaction liquid chromatography. Mobile phases composed of methanol as an organic modifier and four different aqueous parts: (i) deionized water, (ii) aqueous solution of formic acid (pH 2.10), (iii) 20mM ammonium acetate buffer (pH 4.70) and (iv) 10mM ammonium acetate buffer (pH 8.80) in various volume ratios. Newly prepared SBE-β-CD CSP was more suitable for separations of...

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