National Repository of Grey Literature 5 records found  Search took 0.00 seconds. 
Use of hypervalent ionide compounds and MBH carbonates in organocatalysis
Kamlar, Martin ; Veselý, Jan (advisor) ; Pour, Milan (referee) ; Beier, Petr (referee)
Beside transition-metal and enzymatic catalysis plays organocatalysis an important role in asymmetric organic sythesis. In the field of organocatalysis are amines group of compounds commonly used as organocatalysts. This thesis deals with the use of hypervalent iodine compounds in combination with amine catalysis and also with the use of Morita-Baylis-Hillman carbonates in organocatalytic allylic substitution reactions. In the first part an organocatalytic enantioselective α-selenylation reaction of saturated aldehydes using diphenyldiselenide and iodobenzene diacetate is described. Reaction is catalysed by commercially available first generation MacMillan catalyst. The products of the reaction were obtained in yields of 51-70 % and enantiomeric excess 95-99 %. Designed methodology was extended on the derivatives of β-ketoesters by catalysis of tertiary amines and quaternary ammonium salts. Apart from selenylation reactions we have also dealt with the possibility of formation C-C bond using hypervalent iodine compouds. Particularly, we focused on electrophillic alkynylation reactions of appropriate nucleophiles using acetylene-bearing hypervalent iodine compounds. Fluorinated sulfone derivatives and enolizable heterocycles such as pyrazolone derivatives, rhodanines, oxindoles and azlactones were...
Sulfur-based reagents for nucleophilic and radical introduction of tetrafluoroethyl and tetrafluoroethylene groups
Chernykh, Yana ; Beier, Petr (advisor) ; Kvíčala, Jaroslav (referee) ; Církva, Vladimír (referee)
Charles University in Prague, Faculty of Science Department of Organic Chemistry Ing. Yana Chernykh Sulfur-Based Reagents for Nucleophilic and Radical Introduction of Tetrafluoroethyl and Tetrafluoroethylene Groups Ph.D. Thesis Prague 2014 ABSTRACT This project was aimed at developing new methodologies for selective introduction of tetrafluoroethyl and tetrafluoroethylene groups into organic molecules. The study was focused on reactivities of fluorinated sulfones and sulfides as tetrafluoroalkylation reagents. In the Introduction part of the thesis, main aspects of organofluorine chemistry are outlined, illustrating beneficial effects of fluorine atoms on physical, chemical and biological properties of organic compounds. General synthetic methods for the selective introduction of fluorine atoms and fluoroalkyl groups to organic molecules are described. Particular attention is given to reactivity and applications of CF2CF2-containing compounds, indicating challenges in synthetic approaches toward tetrafluoroalkylation. The Results and discussion part describes reactivities of four new fluorinated organosulfur reagents as tetrafluoroethyl and tetrafluoroethylene building blocks. The application of these reagents as various carbanionic or radical synthons proved to be effective for the incorporation of CF2CF2...
Nucleophilic introduction of fluorinated functional groups using organophosphorus compounds.
Opekar, Stanislav ; Beier, Petr (advisor) ; Veselý, Jan (referee) ; Kvíčala, Jaroslav (referee)
In the Introduction part of this thesis, the chemistry of organofluorine compounds is discussed, particularly the methods for the preparation of organofluorine compounds mainly by fluoroalkylation methods. Furthermore, the chemistry of fluorinated phosphonates, methods of their preparation, reactivity and biological activity is discussed. Additionally, the reactivity of fluoromethane derivatives is briefly mentioned and especially, the reactivity of diethyl fluoromalonate and fluorobisfenylsulfonylmethane is described. The Results and discussion part is devoted to the reactivity of three fluorinated phosphonates: tetraethyl fluoromethylenbisphosphonate, diethyl fluorophenylsulfonylphosphonate and previously not described diethyl fluoronitromethylphosphonate. These fluorinated phosphonates belong to the family of nucleophilic monofluoroalkylation reagents, meaning that these compounds are convenient starting materials for the synthesis of complex organic molecules containing the fluorine atom. The results deal with the reactivity of above mentioned fluorinated phosphonates, mainly with alkylation reactions, Horner-Wadsworth-Emmons reactions and conjugated additions. Also, other synthetic methods such as the Mitsunobu reaction or the palladium catalyzed allylation reaction were investigated; however,...
Synthesis and applications of fluorophosphonates
Cherkupally, Prabhakar ; Beier, Petr (advisor) ; Hermann, Petr (referee) ; Kvíčala, Jan (referee)
In the Introduction part of this thesis, the chemistry of organo-fluorine compounds including the electronic properties that fluorine impacts onto organic molecules, steric effects, lipophilicity and other characteristics as well as applications and important features of organo-fluorine compounds are briefly discussed. Moreover, summary of the methods for their preparation, modern methods for fluorinations and enantioselective fluorinations, and fluoroalkylation methodologies in organic synthesis are described. Additionally, the chemistry of fluorinated phosphonates including their preparations, important applications and the chemistry of α,α-difluorophosphonates are discussed. The Results and discussion part describes nucleophilic trifluoromethylation of various electrophilic substrates using diethyl trifluoromethylphosphonate. Furthermore, efficient stereoselective synthesis of fluorovinylphosphonates by a base-induced HF elimination of α,α-difluorophosphonates is explained. In addition, synthesis of number of new, structurally diverse compounds, having a difluorophosphonate moiety using the reaction of diethyl difluoromethylphosphonate with various α,β-unsaturated carbonyl compounds, Michael acceptors and imines are reported. Also, preliminary experiments dealing with nucleophilic reactions of...
Analysis of novel members of FAHFA lipid class derived from omega 3-PUFA by LC-MS/MS and LC-MS/MS/MS
Rombaldová, Martina ; Kuda, Ondřej ; Březinová, Marie ; Slavíková, Barbora ; Pošta, Martin ; Beier, Petr ; Janovská, Petra ; Veleba, J. ; Kopecký Jr., J. ; Kudová, Eva ; Pelikánová, T. ; Kopecký, Jan
White adipose tissue (WAT) is a complex organ with both metabolic and endocrine functions. Dysregulation of all of these functions of WAT, together with low-grade inflammation of the tissue in obesity, contributes to the development of insulin resistance and type 2 diabetes. Omega-3 polyunsaturated fatty acids (PUFA) of marine origin play an important role in resolution of inflammation and exert beneficial metabolic effects. Using LC-MS/MS method, we elucidated the structures of novel members of fatty acid esters of hydroxy fatty acids (FAHFA), which were present in murine and human serum and WAT after omega-3 PUFA supplementation in diet. These compounds contained DHA esterified to 9- and 13-hydroxyoctadecadienoic acid (HLA) termed 9-DHAHLA and 13-DHAHLA, and were synthesized in WAT. Our results document the existence of novel lipid mediators, which are involved in the beneficial anti-inflammatory effects attributed toomega-3 PUFA, in both miceandhumans.

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