38 results on '"Katarzyna Urbaniak"'
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2. (3+2)-Cycloadditions of Levoglucosenone (LGO) with Fluorinated Nitrile Imines Derived from Trifluoroacetonitrile: An Experimental and Computational Study
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Grzegorz Mlostoń, Katarzyna Urbaniak, Marcin Palusiak, Zbigniew J. Witczak, and Ernst-Ulrich Würthwein
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levoglucosenone ,nitrile imines ,(3+2)-cycloadditions ,fluoroalkylated pyrazoles ,DFT calculations ,Organic chemistry ,QD241-441 - Abstract
The in situ-generated N-aryl nitrile imines derived from trifluoroacetonitrile smoothly undergo (3+2)-cycloadditions onto the enone fragment of the levoglucosenone molecule, yielding the corresponding, five-membered cycloadducts. In contrast to the ‘classic’ C(Ph),N(Ph) nitrile imine, reactions with fluorinated C(CF3),N(Ar) analogues lead to stable pyrazolines in a chemo- and stereoselective manner. Based on the result of X-ray single crystal diffraction analysis, their structures were established as exo-cycloadducts with the location of the N-Ar terminus of the 1,3-dipole at the α-position of the enone moiety. The DFT computation demonstrated that the observed reaction pathway results from the strong dominance of kinetic control over thermodynamic control.
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- 2023
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3. Synthesis and selected transformations of 2-unsubstituted 1-(adamantyloxy)imidazole 3-oxides: straightforward access to non-symmetric 1,3-dialkoxyimidazolium salts
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Grzegorz Mlostoń, Małgorzata Celeda, Katarzyna Urbaniak, Marcin Jasiński, Vladyslav Bakhonsky, Peter R. Schreiner, and Heinz Heimgartner
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alkoxyamines ,imidazole N-oxides ,imidazolium salts ,nucleophilic carbenes ,sulfur transfer reaction ,Science ,Organic chemistry ,QD241-441 - Abstract
Adamantyloxyamine reacts with formaldehyde to give N-(adamantyloxy)formaldimine as a room-temperature-stable compound that exists in solution in monomeric form. This product was used for reactions with α-hydroxyiminoketones leading to a new class of 2-unsubstituted imidazole 3-oxides bearing the adamantyloxy substituent at N(1). Their reactions with 2,2,4,4-tetramethylcyclobutane-1,3-dithione or with acetic acid anhydride occurred analogously to those of 1-alkylimidazole 3-oxides to give imidazol-2-thiones and imidazol-2-ones, respectively. Treatment of 1-(adamantyloxy)imidazole 3-oxides with Raney-Ni afforded the corresponding imidazole derivatives without cleavage of the N(1)–O bond. Finally, the O-alkylation reactions of the new imidazole N-oxides with 1-bromopentane or 1-bromododecane open access to diversely substituted, non-symmetric 1,3-dialkoxyimidazolium salts. Adamantyloxyamine reacts with glyoxal and formaldehyde in the presence of hydrobromic acid yielding symmetric 1,3-di(adamantyloxy)-1H-imidazolium bromide in good yield. Deprotonation of the latter with triethylamine in the presence of elemental sulfur allows the in situ generation of the corresponding imidazol-2-ylidene, which traps elemental sulfur yielding a 1,3-dihydro-2H-imidazole-2-thione as the final product.
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- 2019
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4. Ammonium-tagged ruthenium-based catalysts for olefin metathesis in aqueous media under ultrasound and microwave irradiation
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Łukasz Gułajski, Andrzej Tracz, Katarzyna Urbaniak, Stefan J. Czarnocki, Michał Bieniek, and Tomasz K. Olszewski
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catalysis ,green chemistry ,microwave ,N-heterocyclic carbene ,olefin metathesis ,ruthenium ,ultrasound ,Science ,Organic chemistry ,QD241-441 - Abstract
The influence of microwave and ultrasonic irradiation on the performance of ammonium-tagged Ru-based catalysts in olefin metathesis transformations in aqueous media was studied. Differences in the catalytic activity in correlation with the nature of the present counter ion and the size of the N-heterocyclic carbene (NHC) ligand were revealed. The presented methodology allows for preparation of a variety of polar and non-polar metathesis products under environmentally friendly conditions.
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- 2019
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5. First thia-Diels–Alder reactions of thiochalcones with 1,4-quinones
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Grzegorz Mlostoń, Katarzyna Urbaniak, Paweł Urbaniak, Anna Marko, Anthony Linden, and Heinz Heimgartner
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hetero-Diels–Alder reactions ,quinone dyes ,quinones ,sulfur heterocycles ,thiochalcones ,Science ,Organic chemistry ,QD241-441 - Abstract
Aryl and hetaryl thiochalcones react smoothly with 1,4-quinones in THF solution at 60 °C yielding the corresponding fused 4H-thiopyrans after spontaneous dehydrogenation of the initially formed [4 + 2] cycloadducts. In general, the yields of the isolated products were high. With 5-chloro-10-hydroxy-1,4-anthraquinone, the thia-Diels–Alder reaction occurred with complete regioselectivity. In the case of the reaction of vitamin K3 (menadione) with diphenylthiochalcone, the initial cycloadduct was isolated in 37% yield.
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- 2018
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6. Dimerization reactions of aryl selenophen-2-yl-substituted thiocarbonyl S-methanides as diradical processes: a computational study
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Michael L. McKee, Grzegorz Mlostoń, Katarzyna Urbaniak, and Heinz Heimgartner
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1,3-dipolar cycloadditions ,reaction mechanisms ,reactive intermediates ,thiocarbonyl S-methanides ,thioketones ,Science ,Organic chemistry ,QD241-441 - Abstract
An intriguing stepwise diradical mechanism of the dimerization of the reactive intermediate (thiocarbonyl S-methanide) appearing in the reaction of phenyl selenophen-2-yl thioketone with diazomethane was studied by means of computational methods. The preferred formation of the unusual macroheterocycle, competitive with the 1,3-ring closure leading to a thiirane and the head-to-head dimerization yielding a 1,4-dithiane derivative, respectively, was explained based on the analysis of the structure of the favored conformer of the intermediate, delocalized diradical species. The influence of selenium as a ‘heavy atom’ for stabilization of this intermediate has been emphasized.
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- 2017
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7. Hetero-Diels-Alder Reactions of In Situ-Generated Azoalkenes with Thioketones; Experimental and Theoretical Studies
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Grzegorz Mlostoń, Katarzyna Urbaniak, Malwina Sobiecka, Heinz Heimgartner, Ernst-Ulrich Würthwein, Reinhold Zimmer, Dieter Lentz, and Hans-Ulrich Reissig
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(4 + 2)-cycloadditions ,hetero-Diels-Alder reactions ,azoalkenes ,thioketones ,sulfur heterocycles ,organic reaction mechanisms ,Organic chemistry ,QD241-441 - Abstract
The hetero-Diels-Alder reactions of in situ-generated azoalkenes with thioketones were shown to offer a straightforward method for an efficient and regioselective synthesis of scarcely known N-substituted 1,3,4-thiadiazine derivatives. The scope of the method was fairly broad, allowing the use of a series of aryl-, ferrocenyl-, and alkyl-substituted thioketones. However, in the case of N-tosyl-substituted cycloadducts derived from 1-thioxo-2,2,4,4-tetramethylcyclobutan-3-one and the structurally analogous 1,3-dithione, a more complicated pathway was observed. By elimination of toluene sulfinic acid, the initially formed cycloadducts afforded 2H-1,3,4-thiadiazines as final products. Advanced DFT calculations revealed that the observed high regioselectivity was due to kinetic reaction control and that the (4 + 2)-cycloadditions of sterically less unhindered thiones occurred via highly unsymmetric transition states with shorter C..S-distances (2.27–2.58 Å) and longer N..C-distances (3.02–3.57 Å). In the extreme case of the sterically very hindered 2,2,4,4-tetramethylcyclobutan-1,3-dione-derived thioketones, a zwitterionic intermediate with a fully formed C‒S bond was detected, which underwent ring closure to the 1,3,4-thiadiazine derivative in a second step. For the hypothetical formation of the regioisomeric 1,2,3-thiadiazine derivatives, the DFT calculations proposed more symmetric transition states with considerably higher energies.
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- 2021
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8. The Fluoride Anion-Catalyzed Sulfurization of Thioketones with Elemental Sulfur Leading to Sulfur-Rich Heterocycles: First Sulfurization of Thiochalcones
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Grzegorz Mlostoń, Jakub Wręczycki, Katarzyna Urbaniak, Dariusz M. Bieliński, and Heinz Heimgartner
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thioketones ,thiochalcones ,fluoride anion ,elemental sulfur ,sulfur heterocycles ,Organic chemistry ,QD241-441 - Abstract
Fluoride anion was demonstrated as a superior activator of elemental sulfur (S8) to perform sulfurization of thioketones leading to diverse sulfur-rich heterocycles. Due to solubility problems, reactions must be carried out either in THF using tetrabutylammonium fluoride (TBAF) or in DMF using cesium fluoride (CsF), respectively. The reactive sulfurizing reagents are in situ generated, nucleophilic fluoropolysulfide anions FS(8−x)−, which react with the C=S bond according to the carbophilic addition mode. Dithiiranes formed thereby, existing in an equilibrium with the ring-opened form (diradicals/zwitterions) are key-intermediates, which undergo either a step-wise dimerization to afford 1,2,4,5-tetrathianes or an intramolecular insertion, leading in the case of thioxo derivatives of 2,2,4,4-tetramethylcyclobutane-1,3-dione to ring enlarged products. In reactions catalyzed by TBAF, water bounded to fluoride anion via H-bridges and forming thereby its stable hydrates is involved in secondary reactions leading, e.g., in the case of 2,2,4,4-tetramethyl-3-thioxocyclobutanone to the formation of some unexpected products such as the ring enlarged dithiolactone and ring-opened dithiocarboxylate. In contrast to thioketones, the fluoride anion catalyzed sulfurization of their α,β-unsaturated analogues, i.e., thiochalcones is slow and inefficient. However, an alternative protocol with triphenylphosphine (PPh3) applied as a catalyst, offers an attractive approach to the synthesis of 3H-1,2-dithioles via 1,5-dipolar electrocyclization of the in situ-generated α,β-unsaturated thiocabonyl S-sulfides. All reactions occur under mild conditions and can be considered as attractive methods for the preparation of sulfur rich heterocycles with diverse ring-size.
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- 2021
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9. Nitro-Grela-type complexes containing iodides – robust and selective catalysts for olefin metathesis under challenging conditions
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Andrzej Tracz, Mateusz Matczak, Katarzyna Urbaniak, and Krzysztof Skowerski
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green solvents ,macrocyclization ,metathesis ,ruthenium ,Science ,Organic chemistry ,QD241-441 - Abstract
Iodide-containing nitro-Grela-type catalysts have been synthesized and applied to ring closing metathesis (RCM) and cross metathesis (CM) reactions. These new catalysts have exhibited improved efficiency in the transformation of sterically, non-demanding alkenes. Additional steric hindrance in the vicinity of ruthenium related to the presence of iodides ensures enhanced catalyst stability. The benefits are most apparent under challenging conditions, such as very low reaction concentrations, protic solvents or with the occurrence of impurities.
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- 2015
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10. The mood of parents of children who stutter
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Katarzyna Urbaniak
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General Economics, Econometrics and Finance - Abstract
WstępNastrój jest aspektem temperamentu związanym ze stopniem wrażliwości i kierunkiem odpowiedzi emocjonalnej danej osoby, a znacznie mniej z wpływem wydarzeń życiowych. Jednak niepełnosprawność dziecka i opieka nad nim niewątpliwie znajduje odbicie w nastroju jego rodziców.CelCelem niniejszych badań był opis nastroju, jakiego doświadczają rodzice dzieci jąkających się, przy uwzględnieniu czynników związanych z niepełnosprawnością dziecka, a tym samym poznanie wycinka specyfiki funkcjonowania rodziny z dzieckiem jąkającym się.Materiał i metodyW badaniu zastosowano Przymiotnikową Skalę Nastroju G. Matthewsa, A. Chamberlaina, D. M. Jonesa, Kwestionariusz Samopoczucia D. Mc Naira, M. Lorra i L. Dropplemana, Skalę Samooceny i Oceny Jąkania Z. Tarkowskiego i J. Góral-Półroli oraz ankietę osobową. Badaniami objętych zostało 61 rodziców, wychowujących dzieci w wieku od 7 do 15 lat z diagnozą niepłynności mówienia.WynikiAnaliza wyników pokazała, że u badanych rodziców dzieci jąkających się dominuje nastrój negatywny oraz rozemocjonowanie. Zmienne dotyczące głębokości jąkania częściowo różnicują nastrój odczuwany przez badanych rodziców.WnioskiPrzeprowadzone badania pokazują, iż jąkanie u dziecka może być przyczyną wielu konfliktów i problemów emocjonalnych rodziców, jednocześnie wskazują obszary, w których rodzicom dzieci jąkających się należałoby udzielić wsparcia.
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- 2020
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11. Hetero-Diels-Alder Reactions of In Situ-Generated Azoalkenes with Thioketones; Experimental and Theoretical Studies †
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Heinz Heimgartner, Grzegorz Mlostoń, Reinhold Zimmer, Ernst-Ulrich Würthwein, Dieter Lentz, Malwina Sobiecka, Hans-Ulrich Reissig, Katarzyna Urbaniak, and University of Zurich
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10120 Department of Chemistry ,In situ ,Steric effects ,azoalkenes ,DFT computations ,Pharmaceutical Science ,Organic chemistry ,Sulfinic acid ,Ring (chemistry) ,Article ,sulfur heterocycles ,Analytical Chemistry ,500 Naturwissenschaften und Mathematik::540 Chemie::546 Anorganische Chemie ,chemistry.chemical_compound ,QD241-441 ,Computational chemistry ,hetero-Diels-Alder reactions ,540 Chemistry ,Drug Discovery ,(4 + 2)-cycloadditions ,Physical and Theoretical Chemistry ,chemistry.chemical_classification ,Chemistry ,Aryl ,Regioselectivity ,thioketones ,organic reaction mechanisms ,Toluene ,Transition state ,Chemistry (miscellaneous) ,Molecular Medicine ,500 Naturwissenschaften und Mathematik::540 Chemie::540 Chemie und zugeordnete Wissenschaften - Abstract
The hetero-Diels-Alder reactions of in situ-generated azoalkenes with thioketones were shown to offer a straightforward method for an efficient and regioselective synthesis of scarcely known N-substituted 1,3,4-thiadiazine derivatives. The scope of the method was fairly broad, allowing the use of a series of aryl-, ferrocenyl-, and alkyl-substituted thioketones. However, in the case of N-tosyl-substituted cycloadducts derived from 1-thioxo-2,2,4,4-tetramethylcyclobutan-3-one and the structurally analogous 1,3-dithione, a more complicated pathway was observed. By elimination of toluene sulfinic acid, the initially formed cycloadducts afforded 2H-1,3,4-thiadiazines as final products. Advanced DFT calculations revealed that the observed high regioselectivity was due to kinetic reaction control and that the (4 + 2)-cycloadditions of sterically less unhindered thiones occurred via highly unsymmetric transition states with shorter C..S-distances (2.27–2.58 Å) and longer N..C-distances (3.02–3.57 Å). In the extreme case of the sterically very hindered 2,2,4,4-tetramethylcyclobutan-1,3-dione-derived thioketones, a zwitterionic intermediate with a fully formed C‒S bond was detected, which underwent ring closure to the 1,3,4-thiadiazine derivative in a second step. For the hypothetical formation of the regioisomeric 1,2,3-thiadiazine derivatives, the DFT calculations proposed more symmetric transition states with considerably higher energies.
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- 2021
12. Ammonium-tagged ruthenium-based catalysts for olefin metathesis in aqueous media under ultrasound and microwave irradiation
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Michał Bieniek, Stefan J. Czarnocki, Tomasz K. Olszewski, Łukasz Gułajski, Andrzej Tracz, and Katarzyna Urbaniak
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Green chemistry ,microwave ,chemistry.chemical_element ,Metathesis ,Full Research Paper ,Catalysis ,lcsh:QD241-441 ,chemistry.chemical_compound ,lcsh:Organic chemistry ,olefin metathesis ,ruthenium ,lcsh:Science ,chemistry.chemical_classification ,catalysis ,Ligand ,green chemistry ,ultrasound ,Organic Chemistry ,Combinatorial chemistry ,Ruthenium ,Chemistry ,chemistry ,lcsh:Q ,Counterion ,Carbene ,N-heterocyclic carbene ,Microwave - Abstract
The influence of microwave and ultrasonic irradiation on the performance of ammonium-tagged Ru-based catalysts in olefin metathesis transformations in aqueous media was studied. Differences in the catalytic activity in correlation with the nature of the present counter ion and the size of the N-heterocyclic carbene (NHC) ligand were revealed. The presented methodology allows for preparation of a variety of polar and non-polar metathesis products under environmentally friendly conditions.
- Published
- 2019
13. Hetero‐Diels‐Alder Reactions of α‐Nitrosoalkenes with Ferrocenyl, Hetaryl and Cycloaliphatic Thioketones
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Heinz Heimgartner, Reinhold Zimmer, Hans-Ulrich Reissig, Katarzyna Urbaniak, and Grzegorz Mlostoń
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010405 organic chemistry ,Chemistry ,Diels alder ,General Chemistry ,010402 general chemistry ,01 natural sciences ,Medicinal chemistry ,0104 chemical sciences - Published
- 2018
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14. Microwave-assisted reactions of α-diazoketones with hetaryl and ferrocenyl thioketones
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Heinz Heimgartner, Grzegorz Mlostoń, Róża Hamera-Fałdyga, Katarzyna Urbaniak, Małgorzata Jeske, and Magdalena Godziszewska
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chemistry.chemical_compound ,010405 organic chemistry ,Chemistry ,Microwave irradiation ,General Chemistry ,Irradiation ,010402 general chemistry ,Photochemistry ,01 natural sciences ,Toluene ,Microwave assisted ,Microwave ,0104 chemical sciences - Abstract
Differently substituted hetaryl thioketones react with less reactive diazoketones under microwave (MW) irradiation in toluene solution. After only 2 min, the reactions were complete and, depending ...
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- 2017
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15. [3+2]-Cycloadditions of nitrilimines with heteroaryl thioketones
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Korany A. Ali, Grzegorz Mlostoń, Heinz Heimgartner, Anthony Linden, Katarzyna Urbaniak, University of Zurich, and Mlostoń, Grzegorz
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10120 Department of Chemistry ,Crystallography ,010405 organic chemistry ,Chemistry ,540 Chemistry ,X-ray crystallography ,Regioselectivity ,1600 General Chemistry ,General Chemistry ,010402 general chemistry ,01 natural sciences ,0104 chemical sciences - Abstract
The in situ generated nitrilimines are trapped efficiently with heteroaryl thioketones bearing thiophen-2-yl or selenophen-2-yl substituents. The exclusive products observed in these reactions are 2,3-dihydro-1,3,4-thiadiazoles formed via regioselective [3+2]-cycloaddition. Competitive head-to-tail dimerization of the intermediate 1,3-dipoles was not observed in any of the studied reactions.
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- 2017
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16. The use of high-performance liquid chromatography with diode array detector for the determination of sulfide ions in human urine samples using pyrylium salts
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A. Nowicki, Grażyna Chwatko, W. Zgagacz, Katarzyna Urbaniak, Robert Zakrzewski, Department of Environmental Chemistry, Faculty of Chemistry, University of Lodz, Poland, and Department of Organic and Applied Chemistry, Faculty of Chemistry, University of Lodz, Poland
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Sulfide ,Calibration curve ,Hydrogen sulfide ,Clinical Biochemistry ,Human urine sample ,High performance liquid chromatography with diode detector (DAD) ,Sulfides ,030226 pharmacology & pharmacy ,01 natural sciences ,Biochemistry ,High-performance liquid chromatography ,Analytical Chemistry ,03 medical and health sciences ,chemistry.chemical_compound ,0302 clinical medicine ,sole piryliowe ,Limit of Detection ,Chromatography detector ,Pyrylium salts ,Benzene Derivatives ,Humans ,Derivatization ,Chromatography, High Pressure Liquid ,detektor diodowy (DAD) ,chemistry.chemical_classification ,Chromatography ,wysokosprawna chromatografia cieczowa (HPLC) ,Chemistry ,010401 analytical chemistry ,Chlorate ,jon siarczkowy ,mocz ,Reproducibility of Results ,Cell Biology ,General Medicine ,0104 chemical sciences ,Sulfide ions ,Linear Models ,Salts ,Sample collection - Abstract
Hydrogen sulfide is a toxic gas involved in the regulation of some essential biological processes. A novel, precise, accurate and rapid method based on high-performance liquid chromatography with diode array detection for the determination of sulfide ions in human urine sample is proposed. The method involves the derivatization of sulfide with pyrylium salts – (2,4,6-triphenylpyrylium hydrogensulfate(VI) (L1) and 4-[p-(N,N-dimethylamino)phenyl]-2,6-diphenylpyrylium chlorate(VII) (LN1). The separation occurs on InfinityLab Poroshell 120 EC C18 column using acetonitrile and phosphate buffer as a mobile phase. The detectors utilized a wavelength of 371 or 580 nm. The calibration curves were linear in the range of 2–150 μmol L−1 and 1–50 μmol L−1 for L1 and LN1 derivatives, respectively. The samples were found to be stable from sample collection to final analysis. The method was successfully applied to samples from apparently healthy volunteers.
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- 2020
17. 2-Unsubstituted Imidazole N-Oxides as Novel Precursors of Chiral 3-Alkoxyimidazol-2-ylidenes Derived from trans-1,2-Diaminocyclohexane and Other Chiral Amino Compounds
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Peter R. Schreiner, Małgorzata Celeda, Przemysław J. Boratyński, Marcin Jasiński, Heinz Heimgartner, Katarzyna Urbaniak, Grzegorz Mlostoń, University of Zurich, and Mlostoń, Grzegorz
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10120 Department of Chemistry ,1601 Chemistry (miscellaneous) ,carbene sulfurization ,3003 Pharmaceutical Science ,Pharmaceutical Science ,Alkylation ,Medicinal chemistry ,Analytical Chemistry ,chemistry.chemical_compound ,Deprotonation ,chiral nucleophilic carbenes ,Drug Discovery ,540 Chemistry ,imidazole-2-thiones ,Imidazole ,Physical and Theoretical Chemistry ,N-alkoxyimidazolium salts ,Triethylamine ,chemistry.chemical_classification ,1602 Analytical Chemistry ,3002 Drug Discovery ,Organic Chemistry ,trans-1,2-Diaminocyclohexane ,Amino acid ,imidazole N-oxides ,Enantiopure drug ,chemistry ,chiral compounds ,Chemistry (miscellaneous) ,Reagent ,1313 Molecular Medicine ,Molecular Medicine ,1606 Physical and Theoretical Chemistry ,1605 Organic Chemistry - Abstract
&lsquo, Desymmetrization&rsquo, of trans-1,2-diaminocyclohexane by treatment with &alpha, &omega, dihalogenated alkylation reagents leads to mono-NH2 derivatives (&lsquo, primary-tertiary diamines&rsquo, ). Upon reaction with formaldehyde, these products formed monomeric formaldimines. Subsequently, reactions of the formaldimines with &alpha, hydroxyiminoketones led to the corresponding 2-unsubstituted imidazole N-oxide derivatives, which were used here as new substrates for the in situ generation of chiral imidazol-2-ylidenes. Upon O-selective benzylation, new chiral imidazolium salts were obtained, which were deprotonated by treatment with triethylamine in the presence of elemental sulfur. Under these conditions, the intermediate imidazol-2-ylidenes were trapped by elemental sulfur, yielding the corresponding chiral non-enolizable imidazole-2-thiones in good yields. Analogous reaction sequences, starting with imidazole N-oxides derived from enantiopure primary amines, amino alcohols, and amino acids, leading to the corresponding 3-alkoxyimidazole-2-thiones were also studied.
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- 2019
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18. 2-Unsubstituted Imidazole
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Grzegorz, Mlostoń, Małgorzata, Celeda, Marcin, Jasiński, Katarzyna, Urbaniak, Przemysław J, Boratyński, Peter R, Schreiner, and Heinz, Heimgartner
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Cyclohexylamines ,chiral compounds ,carbene sulfurization ,chiral nucleophilic carbenes ,imidazole N-oxides ,Imidazoles ,imidazole-2-thiones ,Oxides ,N-alkoxyimidazolium salts ,Article - Abstract
‘Desymmetrization’ of trans-1,2-diaminocyclohexane by treatment with α,ω-dihalogenated alkylation reagents leads to mono-NH2 derivatives (‘primary-tertiary diamines’). Upon reaction with formaldehyde, these products formed monomeric formaldimines. Subsequently, reactions of the formaldimines with α-hydroxyiminoketones led to the corresponding 2-unsubstituted imidazole N-oxide derivatives, which were used here as new substrates for the in situ generation of chiral imidazol-2-ylidenes. Upon O-selective benzylation, new chiral imidazolium salts were obtained, which were deprotonated by treatment with triethylamine in the presence of elemental sulfur. Under these conditions, the intermediate imidazol-2-ylidenes were trapped by elemental sulfur, yielding the corresponding chiral non-enolizable imidazole-2-thiones in good yields. Analogous reaction sequences, starting with imidazole N-oxides derived from enantiopure primary amines, amino alcohols, and amino acids, leading to the corresponding 3-alkoxyimidazole-2-thiones were also studied.
- Published
- 2019
19. A convenient access to 1,2-diferrocenyl-substituted ethylenes via [3 + 2]-cycloelimination of 2-silylated 4,4,5,5-tetrasubstituted 1,3-dithiolanes
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Heinz Heimgartner, Wolfgang Weigand, Grzegorz Mlostoń, Róża Hamera-Fałdyga, Katarzyna Urbaniak, University of Zurich, and Mlostoń, Grzegorz
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chemistry.chemical_classification ,10120 Department of Chemistry ,Trimethylsilyl ,010405 organic chemistry ,Diazomethane ,Substituent ,1600 General Chemistry ,General Chemistry ,010402 general chemistry ,01 natural sciences ,Medicinal chemistry ,0104 chemical sciences ,chemistry.chemical_compound ,chemistry ,Group (periodic table) ,540 Chemistry ,Alkyl - Abstract
Ferrocenyl thioketones bearing a hetaryl, phenyl or alkyl group as the second substituent react with (trimethylsilyl)diazomethane at ca. −30°C in THF solution without formation of a stable [3 + 2]-...
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- 2018
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20. Selenophen-2-yl-Substituted Thiocarbonyl Ylides - at the Borderline of Dipolar and Biradical Reactivity
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Katarzyna Urbaniak, Anthony Linden, Grzegorz Mlostoń, Heinz Heimgartner, University of Zurich, and Mlostoń, Grzegorz
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10120 Department of Chemistry ,Steric effects ,1303 Biochemistry ,1503 Catalysis ,Stereochemistry ,Substituent ,Ring (chemistry) ,Biochemistry ,Catalysis ,Inorganic Chemistry ,chemistry.chemical_compound ,540 Chemistry ,Drug Discovery ,Reactivity (chemistry) ,Thioketone ,Physical and Theoretical Chemistry ,chemistry.chemical_classification ,1604 Inorganic Chemistry ,3002 Drug Discovery ,Aryl ,Organic Chemistry ,Cycloaddition ,chemistry ,Ylide ,1606 Physical and Theoretical Chemistry ,1605 Organic Chemistry - Abstract
The reactions of aryl (selenophen-2-yl) thioketones with CH2N2 occur with spontaneous elimination of N2, even at low temperature (−65°), to give regioselectively sterically crowded 4,4,5,5-tetrasubstituted 1,3-dithiolanes and/or a novel type of twelve-membered dithia-diselena heterocycles as dimers of the transient thiocarbonyl S-methanides. The ratio of these products depends on the type of substituent located at C(4) of the phenyl ring. Whereas the formation of the 1,3-dithiolanes corresponds to a [3+2] cycloaddition of an intermediate thiocarbonyl ylide with the starting thioketone, the twelve-memberd ring has to be formed via dimerization of the ‘thiocarbonyl ylide’ with an extended biradical structure.
- Published
- 2015
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21. Hetaryl Thioketones: Synthesis and Selected Reactions
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Paulina Grzelak, Heinz Heimgartner, Krzysztof Gębicki, Katarzyna Urbaniak, and Grzegorz Mlostoń
- Subjects
Dimethyl acetylenedicarboxylate ,chemistry.chemical_compound ,chemistry ,Diazomethane ,Reagent ,Furan ,Thiophene ,Regioselectivity ,Organic chemistry ,chemistry.chemical_element ,General Chemistry ,Oxygen ,Sulfur - Abstract
A series of phenyl/hetaryl and bishetaryl thioketones have been prepared via oxygen/sulfur exchange of the corresponding ketones by treatment with Lawesson’s reagent. The nonsymmetrical ketones were conveniently accessible via the reactions of lithiated furan, thiophene, and selenophene with N,N-dimethylbenzamide and hetarylcarboxamides, respectively, whereas the symmetrical ketones were obtained by treatment of ethyl N,N-dimethylcarbamate with 2 equiv of lithiated heterocycles. Under typical conditions, selected examples of the hetaryl thioketones were oxidized selectively to give thiocarbonyl S-oxides (sulfines). Reactions with diazomethane at –65°C yielded 1,3-dithiolanes in a regioselective manner and hetero-Diels–Alder reactions of 2-thienyl substituted thioketones with dimethyl acetylenedicarboxylate yielded the corresponding 7H-thieno[2,3- c]thiopyran-4,5-dicarboxylates.
- Published
- 2014
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22. Dimerization reactions of aryl selenophen-2-yl-substituted thiocarbonyl
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Michael L, McKee, Grzegorz, Mlostoń, Katarzyna, Urbaniak, and Heinz, Heimgartner
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Chemistry ,reaction mechanisms ,Organic Chemistry ,thiocarbonyl S-methanides ,thioketones ,reactive intermediates ,1,3-dipolar cycloadditions ,Full Research Paper - Abstract
An intriguing stepwise diradical mechanism of the dimerization of the reactive intermediate (thiocarbonyl S-methanide) appearing in the reaction of phenyl selenophen-2-yl thioketone with diazomethane was studied by means of computational methods. The preferred formation of the unusual macroheterocycle, competitive with the 1,3-ring closure leading to a thiirane and the head-to-head dimerization yielding a 1,4-dithiane derivative, respectively, was explained based on the analysis of the structure of the favored conformer of the intermediate, delocalized diradical species. The influence of selenium as a ‘heavy atom’ for stabilization of this intermediate has been emphasized.
- Published
- 2016
23. Synthesis of Optically Active 1-(1-Phenylethyl)-1H-imidazoles Derived from 1-Phenylethylamine
- Author
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Heinz Heimgartner, Katarzyna Urbaniak, Paulina Mucha, Karolina Broda, and Grzegorz Mlostoń
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chemistry.chemical_classification ,Ketone ,Chemistry ,Organic Chemistry ,Formaldehyde ,Optically active ,Biochemistry ,Catalysis ,Inorganic Chemistry ,chemistry.chemical_compound ,1-Phenylethylamine ,Yield (chemistry) ,Drug Discovery ,Organic chemistry ,Physical and Theoretical Chemistry ,Deoxygenation - Abstract
The three-component reaction of (R)- or (S)-1-phenylethylamine (6), formaldehyde, and an α-(hydroxyimino) ketone 5, i.e., 3-(hydroxyimino)butan-2-one (5a) or 2-(hydroxyimino)-1,2-diphenylethanone (5b), yields the corresponding enantiomerically pure 1-(1-phenylethyl)-1H-imidazole 3-oxide 7 in high yield (Schemes 2 and 3). The reactions are carried out either in MeOH or in AcOH. Smooth transformations of the N-oxides into optically active 1-(1-phenylethyl)-1H-imidazoles 10 and 2,3-dihydro-1-(1-phenylethyl)-1H-imidazole-2-thiones 11 are achieved by treatment of 7 with Raney-Ni and 2,2,4,4-tetramethyl-3-thioxocyclobutanone (12), respectively (Scheme 4).
- Published
- 2008
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24. Nitro-Grela-type complexes containing iodides - robust and selective catalysts for olefin metathesis under challenging conditions
- Author
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Mateusz Matczak, Katarzyna Urbaniak, Andrzej Tracz, and Krzysztof Skowerski
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Steric effects ,inorganic chemicals ,macrocyclization ,Chemistry ,Organic Chemistry ,chemistry.chemical_element ,Metathesis ,Combinatorial chemistry ,Full Research Paper ,Catalysis ,Ruthenium ,lcsh:QD241-441 ,Ring-closing metathesis ,lcsh:Organic chemistry ,Nitro ,Ring-opening metathesis polymerisation ,Organic chemistry ,lcsh:Q ,metathesis ,lcsh:Science ,green solvents ,ruthenium ,Acyclic diene metathesis - Abstract
Iodide-containing nitro-Grela-type catalysts have been synthesized and applied to ring closing metathesis (RCM) and cross metathesis (CM) reactions. These new catalysts have exhibited improved efficiency in the transformation of sterically, non-demanding alkenes. Additional steric hindrance in the vicinity of ruthenium related to the presence of iodides ensures enhanced catalyst stability. The benefits are most apparent under challenging conditions, such as very low reaction concentrations, protic solvents or with the occurrence of impurities.
- Published
- 2015
25. [2 + 3]-Cycloadditions of PhosphonodithioformateS-Methanides with CS, NN, and CC Dipolarophiles
- Author
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Mihaela Gulea, Anthony Linden, Serge Masson, Heinz Heimgartner, Katarzyna Urbaniak, and Grzegorz Mlostoń
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Steric effects ,Chemistry ,Stereochemistry ,Organic Chemistry ,Maleic anhydride ,Biochemistry ,Medicinal chemistry ,Catalysis ,Inorganic Chemistry ,chemistry.chemical_compound ,Yield (chemistry) ,Drug Discovery ,Structural isomer ,Physical and Theoretical Chemistry ,Thiobenzophenone - Abstract
The reaction of the methyl (dialkoxyphosphinyl)-dithioformates (= methyl dialkoxyphosphinecarbodithioate 1-oxides) 10 with CH2N2 at − 65° in THF yielded cycloadducts which eliminated N2 between − 40 and − 35° to give the corresponding phosphonodithioformate S-methanides ( =methylenesulfonium (dialkoxyoxidophosphino)(methylthio)methylides) 11 (Scheme 3). These reactive 1,3-dipoles were intercepted by aromatic thioketones to yield 1,3-dithiolanes. Whereas the reaction with thiobenzophenone (12b) led to the sterically more congested isomers 15 regioselectively, a mixture of both regioisomers was obtained with 9H-fluorene-9-thione (12a). Trapping of 11 with phosphono- and sulfonodithioformates led exclusively to the sterically less hindered 1,3-dithiolanes 16 and 18, respectively (Scheme 4). In addition, reactive CC dipolarophiles such as ethenetetracarbonitrile, maleic anhydride, and N-phenylmaleimide as well as the NN dipolarophile dimethyl diazenedicarboxylate were shown to be efficient interceptors of 11 (Scheme 5).
- Published
- 2005
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26. Chromatographic Investigation of Dyes Extracted from Coptic Textiles from the National Museum in Warsaw
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Marek Wróbel, Izabella Surowiec, Bogdan Szostek, Jowita Orska-Gawryś, Katarzyna Urbaniak-Walczak, Jerzy Kehl, and Marek Trojanowicz
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Cochineal ,Chromatography ,biology ,Chemistry ,Elemental analysis ,National museum ,Mordant ,Conservation ,biology.organism_classification ,Spectroscopy ,Diode array ,Fluorescence ,High-performance liquid chromatography - Abstract
This work aimed to identify natural dyes in extracts from Coptic fibres. The objects examined originate from fourth- to twelfthcentury AD Egypt. Chromatographic separations of all the samples were carried out using reversed-phase HPLC (high performance liquid chromatography) with UV- Vis detection and fluorescence detection. Fluorescence detection proved to be better than UV- Vis diode array detection for the determination of some compounds. Selected samples were analysed with HPLC-MS (HPLC-mass spectroscopy) which confirmed the LC-UV findings and allowed the detection and identification of additional compounds. Most of the dyes mentioned in the literature as having been used by Copts were detected: Armenian cochineal, flavonoid yellow dyes, indigotin, lac dye, madder and tannins. Some new compositions ofsignificant colours were also discovered, which had not been reported previously in Coptic textiles. Elemental analysis using SEM-EDS (scanning electron microscopy-energy dispersive spectroscopy) was performed to identify mordants.
- Published
- 2004
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27. Role of C−H···S and C−H···N Hydrogen Bonds in Organic Crystal StructuresThe Crystal and Molecular Structure of 3-Methyl-2,4-diphenyl-(1,3)-thiazolidine-5-spiro-2‘-adamantane and 3-Methyl-2,4,5,5-tetraphenyl-(1,3)-thiazolidine
- Author
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Małgorzata Domagała, Sławomir J. Grabowski, and Katarzyna Urbaniak, and Grzegorz Mlostoń
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Crystal ,chemistry.chemical_compound ,Crystallography ,chemistry ,Proton ,Hydrogen bond ,Intramolecular force ,Adamantane ,Thiazolidine ,Molecule ,Crystal structure ,Physical and Theoretical Chemistry - Abstract
The crystal and molecular structures of 3-methyl-2,4-diphenyl-(1,3)-thiazolidine-5-spiro-2‘-adamantane and 3-methyl-2,4,5,5-tetraphenyl-(1,3)-thiazolidine are investigated showing the existence of C(sp2)−H···S and C(sp2)−H···N intramolecular contacts. The use of the Bader theory shows that C−H...S interactions existing in crystal structures may be treated as weak H bonds. The C−H...N and C−H...S interactions are also analyzed here for simple modeled complexes of (1,3)-thiazolidine as the proton acceptor and simple proton donators: HF, H2O, C2H4, and C2H2 molecules. The calculations for these complexes were performed within the DFT method, B3LYP/6-311++G** level of theory. The bond critical points (BCPs) were found for these modeled systems and the analysis of the electron densities and their Laplacians at BCPs was performed.
- Published
- 2003
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28. Thermal [2+2]-cycloadditions of diphenylketene with aryl- and hetaryl-substituted thioketones
- Author
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Grzegorz Mlostoń, Heinz Heimgartner, Katarzyna Urbaniak, Anna Szychowska, Anthony Linden, University of Zurich, and Mlostoń, Grzegorz
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Pharmacology ,10120 Department of Chemistry ,1602 Analytical Chemistry ,3004 Pharmacology ,Organic Chemistry ,540 Chemistry ,Analytical Chemistry ,1605 Organic Chemistry - Published
- 2015
29. Exploration of fluoral hydrazones derived from carbohydrazides for the synthesis of trifluoromethylated heterocycles
- Author
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Katarzyna Urbaniak, Heinz Heimgartner, Grzegorz Mlostoń, Anthony Linden, Natalia Jacaszek, University of Zurich, and Mlostoń, Grzegorz
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Pharmacology ,10120 Department of Chemistry ,1602 Analytical Chemistry ,Fluoral hydrate ,Organic Chemistry ,Molecular sieve ,Analytical Chemistry ,Mercaptoacetic acid ,chemistry.chemical_compound ,Acetic anhydride ,3004 Pharmacology ,chemistry ,540 Chemistry ,Organic chemistry ,Methanol ,Benzene ,1605 Organic Chemistry - Abstract
The reaction of fluoral hydrate with carbohydrazides in methanol in the presence of molecular sieves (4 A) gave the desired N-acylated fluoral hydrazones (3a–f) in fair yields. Treatment of the latter with mercaptoacetic acid in benzene led to the corresponding 2-trifluoromethyl-1,3-thiazolidinone derivatives (4a–f), whereas the reaction with acetic anhydride gave 3-acetyl-2,3-dihydro-2-trifluoromethyl-1,3,4-oxadiazoles (5a–f). The structures of each type of product have been established by X-ray crystallography.
- Published
- 2014
30. Nucleophilic trifluoromethylation of aziridinyl ketones: A convenient access to fluorinated aziridinyl alcohols
- Author
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Grzegorz Mlostoń, Krzysztof Matyszewski, Anthony Linden, Emilia Obijalska, Katarzyna Urbaniak, Heinz Heimgartner, Paulina Ziębacz, University of Zurich, and Mlostoń, Grzegorz
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10120 Department of Chemistry ,Trifluoromethyl ,1303 Biochemistry ,Trifluoromethylation ,Chemistry ,1604 Inorganic Chemistry ,Organic Chemistry ,Diastereomer ,Grignard reaction ,Biochemistry ,Inorganic Chemistry ,(trifluoromethyl)-trimethylsilane ,chemistry.chemical_compound ,Nucleophile ,Reagent ,2304 Environmental Chemistry ,540 Chemistry ,Environmental Chemistry ,Organic chemistry ,Physical and Theoretical Chemistry ,1606 Physical and Theoretical Chemistry ,1605 Organic Chemistry - Abstract
A convenient synthesis of α-(aziridin-2-yl)-α-(trifluoromethyl) alcohols starting with ethyl aziridine-2-carboxylates is reported. Grignard reaction with the corresponding Weinreb amides led to aziridin-2-yl ketones, and subsequent treatment with Ruppert-Prakash reagent gave the trimethylsilylated target compounds as mixtures of diastereoisomers, which were desilylated with TBAF. In the case of ethyl 1-((S)-1-phenylethyl)aziridine-2-carboxylate, (S,S)- and (S,R)-aziridin-2-yl ketones were obtained, separated chromatographically and transformed into the desired enantiomerically pure α-trifluoromethylated alcohols.
- Published
- 2013
31. A new approach to 2,2-disubstituted 1-(methylsulfanyl)vinyl phosphonates via an intermediate thiocarbonyl ylide
- Author
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Heinz Heimgartner, Katarzyna Urbaniak, Grzegorz Mlostoń, Anthony Linden, and University of Zurich
- Subjects
chemistry.chemical_classification ,10120 Department of Chemistry ,Electrocyclic reaction ,1303 Biochemistry ,3002 Drug Discovery ,Organic Chemistry ,chemistry.chemical_element ,Biochemistry ,Chemical synthesis ,Medicinal chemistry ,Sulfur ,Flue-gas desulfurization ,chemistry ,Ylide ,Yield (chemistry) ,Drug Discovery ,540 Chemistry ,Organic chemistry ,Selectivity ,1605 Organic Chemistry - Abstract
The reaction of methyl (diethylphosphoryl)dithioformate (6) with diaryldiazomethanes 7a–d in THF at −60 °C to room temperature followed by desulfurization is shown to be a convenient method for the preparation of 2,2-disubstituted 1-(methylsulfanyl)vinyl phosphonates 8a–d. The analogous reactions with 2-diazoacenaphthen-1-one (7f) or 2-diazocamphor (7g) in refluxing THF yield selectively the corresponding (Z)- and (E)-vinyl phosphonates 8f and 8g, respectively. These products can be easily oxidized to the vinylsulfoxides 13 and vinylsulfones 14. On the other hand, methyl (diethylphosphoryl)dithioformate (6) and 2-diazo-1,2-diphenylethanone (7e) in boiling THF react to give the 1,3-oxathiole 12. All these reactions occur via an intermediate thiocarbonyl ylide 11 followed by 1,3-dipolar electrocyclization and sulfur extrusion or 1,5-dipolar electrocyclization.
- Published
- 2009
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32. ChemInform Abstract: Reactions of 9H-Fluorene-9-thione with (Trimethylsilyl)diazomethane
- Author
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Heinz Heimgartner, Anthony Linden, Katarzyna Urbaniak, and Grzegorz Mlostoń
- Subjects
chemistry.chemical_classification ,Trimethylsilyl ,Chemistry ,Stereochemistry ,Diazomethane ,Maleic anhydride ,General Medicine ,Medicinal chemistry ,Thiophene derivatives ,chemistry.chemical_compound ,Ylide ,Maleimide ,9H-fluorene ,Derivative (chemistry) - Abstract
The [3+2]-cycloaddition of (trimethylsilyl)diazomethane (7) with 9H-fluorene-9-thione (1) at –60°C yields the spirocyclic 2,5-dihydro-5-trimethylsilyl-1,3,4-thiadiazole 10, which eliminates nitrogen at room temperature to give the 1,4-dithiane derivative 13 by dimerization of the intermediate fluorenethione (trimethylsilyl)methanide (11). This thiocarbonyl ylide can be trapped by 1 to give the 2-trimethylsilyl-1,3-dithiolane 14 via [3+2]-cycloaddition. Furthermore, the 1,3-dipole 11 undergoes successfully [3+2]-cycloadditions with the C=S group of the phosphonyldithioformate 15 as well as with the C=C dipolarophiles maleic anhydride (18a) and N-(cyclohexyl)maleimide (18b). The structures of 13 and 14 have been established by X-ray crystallography.
- Published
- 2008
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33. Reactions of polycyclic thioketones with a phosphonylated carbanion
- Author
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Grzegorz Mlostoń, Heinz Heimgartner, Katarzyna Urbaniak, Emilia Obijalska, University of Zurich, and Mloston, G
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chemistry.chemical_classification ,10120 Department of Chemistry ,Quenching (fluorescence) ,Heteroatom ,chemistry.chemical_element ,Salt (chemistry) ,1600 General Chemistry ,General Chemistry ,Medicinal chemistry ,chemistry.chemical_compound ,chemistry ,General chemistry ,540 Chemistry ,Organic chemistry ,Lithium ,Thioketone ,Alkyl ,Carbanion - Abstract
Polycyclic, nonenolizable cycloaliphatic thioketones 1a and 1b react smoothly with the lithium salt of diethyl methylphosphonate 7 in THF solution at −40°C to afford products of the carbophilic attack exclusively. Quenching of the obtained lithium thiolates with alkyl iodides yields sulfanes of type 9 or 11, respectively, in good yields. 1-Fluoro-2,4-dinitrobenzene was shown to act as an arylating agent. In the case of the “cage” thioketone 1b, the carbanion of salt 7 approaches the CS bond from the exo-side exclusively. In contrast to the parent carbonyl compounds, thioketones 1 show no tendency to undergo the conversion analogous to the Horner–Wadsworth–Emmons reaction, which would result in the formation of an olefinic product. © 2008 Wiley Periodicals, Inc. Heteroatom Chem 19:182–187, 2008; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/hc.20390
- Published
- 2008
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34. Strained 1-Azabicyclo[1.1.0]butanes in the Synthesis of Azetidinethiocarboxylate Derivatives
- Author
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Grzegorz Mlostoń, Heinz Heimgartner, Marta Woznicka, Katarzyna Urbaniak, University of Zurich, and Woznicka, M
- Subjects
Pharmacology ,Thiophosgene ,10120 Department of Chemistry ,1602 Analytical Chemistry ,Chemistry ,Organic Chemistry ,Azetidine ,Butane ,General Medicine ,Chloride ,Medicinal chemistry ,Analytical Chemistry ,chemistry.chemical_compound ,3004 Pharmacology ,540 Chemistry ,medicine ,Organic chemistry ,Methanol ,medicine.drug ,1605 Organic Chemistry - Abstract
The reaction of 3-phenyl-1-azabicyclo[1.1.0]butane (1a) with chlorodithio-formates (5) at room temperature yielded 3-chloro-3-phenylazetidine-1-carbodithioates (6). The same products were obtained in a two-step procedure by treatment of 1a with thiophosgene to give azetidine-1-carbothioyl chloride (7a), followed by treatment with the corresponding sulfane. 3-Chloro-3-phenylazetidine-1-thiocarbamides (8) and the corresponding O-methyl 1-carbothioates (9) were prepared by the reaction of compounds (7) with amines and methanol, respectively. These reactions open a new access to derivatives of azetidine-1-carboxylic acid.
- Published
- 2007
- Full Text
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35. High-Performance Isocyanide Scavengers for Use in Low-Waste Purification of Olefin Metathesis Products
- Author
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Krzysztof Skowerski, Katarzyna Urbaniak, Celina Wierzbicka, Karol Grela, Grzegorz Szczepaniak, and Krzysztof Kosiński
- Subjects
Models, Molecular ,Isocyanide ,General Chemical Engineering ,Molecular Conformation ,chemistry.chemical_element ,Alkenes ,Metathesis ,Ruthenium ,Catalysis ,isocyanides ,chemistry.chemical_compound ,Ring-opening metathesis polymerisation ,Organic chemistry ,Environmental Chemistry ,General Materials Science ,Waste Products ,Cyanides ,Quenching (fluorescence) ,Silica gel ,Full Papers ,Silicon Dioxide ,Scavenger (chemistry) ,scavengers ,General Energy ,chemistry ,olefins ,metathesis ,Methane - Abstract
Three isocyanides containing a tertiary nitrogen atom were investigated for use as small-molecule ruthenium scavenging agents in the workup of olefin metathesis reactions. The proposed compounds are odorless, easy to obtain, and highly effective in removing metal residues, sometimes bringing the metal content below 0.0015 ppm. The most successful of the tested compounds, II, performs very well, even with challenging polar products. The performance of these scavengers is compared and contrasted with other known techniques, such as silica gel filtration and the use of self-scavenging catalysts. As a result, a new hybrid purification method is devised, which gives better results than using either a self-scavenging catalyst or a scavenger alone. Additionally, isocyanide II is shown to be a deactivating (reaction quenching) agent for olefin metathesis and superior to ethyl vinyl ether.
- Published
- 2015
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36. Cover Picture: High-Performance Isocyanide Scavengers for Use in Low-Waste Purification of Olefin Metathesis Products (ChemSusChem 24/2015)
- Author
-
Krzysztof Kosiński, Karol Grela, Grzegorz Szczepaniak, Krzysztof Skowerski, Celina Wierzbicka, and Katarzyna Urbaniak
- Subjects
chemistry.chemical_compound ,General Energy ,Olefin metathesis ,chemistry ,General Chemical Engineering ,Isocyanide ,Environmental Chemistry ,chemistry.chemical_element ,Organic chemistry ,General Materials Science ,Cover (algebra) ,Metathesis ,Ruthenium - Published
- 2015
- Full Text
- View/download PDF
37. Dimethyl 3,4,5,5-tetraphenyl-1,3-thiazolidine-2,2-dicarboxylate and 3,3-dichloro-2,2,4,4,3'-pentamethyl-r-2',t-4'-diphenylcyclobutane-1-spiro-5'-1,3-thiazolidine
- Author
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Sławomir J. Grabowski, Katarzyna Urbaniak, Małgorzata Domagała, Manfred Zabel, Marcin Palusiak, Grzegorz Mlostoń, and Arno Pfitzner
- Subjects
Hydrogen bond ,ddc:540 ,Thiazolidine ,Space group ,General Medicine ,Crystal structure ,Ring (chemistry) ,General Biochemistry, Genetics and Molecular Biology ,chemistry.chemical_compound ,Crystallography ,chemistry ,540 Chemie ,Orthorhombic crystal system ,Unit (ring theory) ,Monoclinic crystal system - Abstract
The first of the title compounds, C31H27NO4S, (V), crystallizes in the monoclinic space group P21/c with two independent molecules in the asymmetric unit, while the second, C23H27Cl2NS, (IX), crystallizes in the orthorhombic space group Pbca with one molecule in the asymmetric unit. In both crystal structures, the 1,3-thiazolidine ring adopts a half-chair conformation. The crystal structures are stabilized by weak C—H⋯O and C—H⋯Cl hydrogen bonds in (V) and (IX), respectively.
- Published
- 2004
38. Addition of diazomethane to phosphonodithioformates and reactions of phosphonylated thiocarbonyl S-methylides
- Author
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Mihaela Gulea, Katarzyna Urbaniak, Heinz Heimgartner, Grzegorz Mlostoń, Serge Masson, University of Zurich, and Mlostoń, Grzegorz
- Subjects
10120 Department of Chemistry ,chemistry.chemical_compound ,Chemistry ,Diazomethane ,Reagent ,Dimer ,540 Chemistry ,Thermal decomposition ,1600 General Chemistry ,General Medicine ,31p nmr spectroscopy ,Methanol ,Photochemistry - Abstract
The reaction of phosphonodithioformates 14 with diazomethane at –60°C yielded 2,5-dihydro-1,3,4-thiadiazoles 15 as unstable intermediates. Their structure was evidenced by the base-catalyzed elimination of methylsulfane leading to 1,3,4-thiadiazole-2-phosphonates. At ca. –35°C, thermal decomposition of 15 by N2-elimination led to reactive thiocarbonyl S-methylides 17. In the absence of trapping reagents, these 1,3-dipoles undergo a head-to-head dimerization leading to 1,4-dithianes 18. An intermediate zwitterionic dimer 19 was detected by 31P NMR spectroscopy. The initially formed thiocarbonyl S-methylide 17 as well as an open-chain zwitterionic dimer 20 was intercepted by methanol. Stable interception products were also obtained with S- and N-nucleophiles.
Catalog
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