National Repository of Grey Literature 32 records found  beginprevious22 - 31next  jump to record: Search took 0.00 seconds. 
Preparation of mono-aryl-per-6-(methylsulfanyl) derivatives of beta-cyclodextrin usable as selectors for detection of hydrocarbons
Zima, Václav ; Jindřich, Jindřich (advisor) ; Machara, Aleš (referee)
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
Development of new methods for the synthesis of compounds containing the pyridine ring
Frejka, David ; Kotora, Martin (advisor) ; Machara, Aleš (referee)
Tato diplomová práce se zabývá novými reakcemi v oblasti katalytických aktivací C-C vazeb v substrátech obsahující pnuté kruhy a jejich následné funkcionalizace při reakcích s trojnou vazbou alkynů vedoucí k rychlé a jednoduché přípravě regioselektivně substituovaných polyaromatických derivátů. V rámci této práce byly vyvinuty vůbec první postupy umožňující selektivní aktivace C-C vazeb v nesymetricky substituovaných systémech (1-azabifenylenech) vůči pnutému kruhu a jejich reakce se substituovanými alkyny na principu cyklotrimerizace. Místo inserce alkynu může být ovlivněno použitím některých katalytických systémů obsahující iridiové a rhodiové komplexy (schéma 1). Tento postup umožňuje jednoduchou, přímočarou a efektivní přípravu derivátů benzochinolinových skeletů, které jsou hojně využívány v mnoha oblastech chemie. Schéma 1 Regioselektivní aktivace C-C vazeb v 1-azabifenylenech Klíčová slova: aktivace C-C vazeb, 1-azabifenylen, cyklotrimerizace, inserce
Preparation of 3-phenylpentanoic and 3-phenylpent-2-enoic acid derivatives
Fatka, David ; Machara, Aleš (advisor) ; Veselý, Jan (referee)
This Bachelor's thesis deals with preparation of the intermediates of the analgesic tapentadol. The chosen synthetic strategy requires a preparation of appropriate derivatives of 3-phenylpentanoic and 3-phenylpent-2-enoic acid. Synthesis of those derivatives represents the cornerstone of the thesis. In the first part, the thesis describes an effort associated with a preparation of 1-[(3-benzyloxy)phenyl]propan-1-one, a necessary intermediate for the preparation of the titled compounds. Then addition reactions were studied on the aforementioned ketone. The second part of the thesis focuses on one particular addition, a Reformatsky reaction, and deals with further optimization. In addition, the submitted thesis also describes variety of attempts to carry out dehydration of the Reformatsky adducts, namely, benzylic tertiary alcohols. Powered by TCPDF (www.tcpdf.org)
pi-Conjugated oligomers comprising helically chiral units
Houska, Václav ; Starý, Ivo (advisor) ; Machara, Aleš (referee)
The synthesis of large, shape-persistent, trimeric macrocycles comprising helical units was investigated. Since the previous synthetic approaches studied in our group failed (mainly alkene and alkyne ring closing metathesis), a more robust route toward the desired macrocycle was sought. A sequential construction of an acyclic trimer employing cross- coupling reactions was expected to overcome the unwanted oligomerization encountered in the case of the earlier metathesis approaches. The closure of the trimer would be accomplished via the intramolecular McMurry reaction or alkene metathesis. An optimized synthesis of the solubilized dibenzo[5]helicene and its derivatives was developed. These compounds served as proposed building blocks of the acyclic trimer. Both Heck and Suzuki- Miyaura couplings used for the preparation of the acyclic trimers provided mixtures containing the desired trimers but the Suzuki-Miyaura reaction proved to be much more efficient. However, the solubility of the trimers turned out to be very low, making the separation of the pure products from the mixture impossible and seriously limiting the further synthetic progress. Only alkene metathesis of the corresponding divinyltrimer was accomplished and despite a low solubility of the starting material, the MS analysis of the...
Synthesis and properties of complex π-electron systems with helical chirality
Houska, Václav ; Stará, Irena (advisor) ; Machara, Aleš (referee)
Planar shape-persistent macrocycles have been known for a long time and are routinely synthesized today. Non-planar 3D structures, however, still remain challenging synthetic targets in many cases. The objective of this Thesis was to develop a synthetic route to shape-persistent macrocycles containing dibenzo[5]helicene or its derivatives as structural units employing alkene and alkyne metathesis. The Introduction focuses on various methods of the macrocycle synthesis, on alkyne metathesis, and synthesis of helicenes is shortly reviewed as well. Then, the first part of Results and discussion describes the synthesis of 3,16-dichlorodibenzo[5]helicene and its derivatives. In the second part, the macrocycle synthesis from these dibenzohelicenes is discussed. The Experimental part provides a detailed description of performed experiments along with characterization of all new compounds prepared.
Cycloaddition of 3-(deoxyribos-1-yl)propynoate with alkynes
Kulhavá, Lucie ; Kotora, Martin (advisor) ; Machara, Aleš (referee)
The object of this work is development of method for a syntesis of Dewar benzenes bearing the deoxyriboside group. The synthesis was based on ethynylation of halogenose resulting in the formation of a mixture of anomeric ethynyldeoxiriboses, which was followed by silylation and separation of individiual anomers. After removal of the silyl group the isomerically pure ethynyldeoxyriboses were transformed into corresponding propynoates that were the key substance for the formation od Dewar benzenes. The reaction of the propynoates with the tetramethylcyclobutadiene-aluminium trichloride complex provided the desired Dewar benzenes bearing the deoxyribose group. Finally, rearrangement of the formed Dewar benzenes to 1-aryldeoxyriboses was studied under thermal and photochemical conditions. Keywords: cycloaddition, arenes, Dewar benzene

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