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Wyświetlanie 1-4 z 4
Tytuł:
2,2'- Dihydroksy-1,1'-binaftyl (BINOL ) i jego pochodne. Wybrane syntezy i zastosowanie. Część I
2,2'-Dihydroxy -1,1'-binaphthyl (BINOL ) and its derivatives: Selected synthesis methods and applications. Part I
Autorzy:
Krasowska, D.
Powiązania:
https://bibliotekanauki.pl/articles/172527.pdf
Data publikacji:
2012
Wydawca:
Polskie Towarzystwo Chemiczne
Tematy:
BINOL
atropoizomery
utleniające sprzęganie
enancjoselektywna synteza
chiralne ligandy
atropoisomers
oxidative coupling
optical resolution
enantioselective synthesis
chiral ligands
Opis:
1,1’-Binaphthyl and its derivatives represent a particular class of chemical molecules which chirality results from the restricted rotation about single bond of the two naphthalene rings. This generates the chirality axis. Therefore 1,1’-binaphthyl derivatives exist as two enantiomeric forms called atropoisomers. Moreover, 1,1’- binaphthyls with substituents at 2,2’ position exhibit higher rotational barriers around the 1,1’-axis, which affect a very stable chiral configuration. The classical examples of such molecules is 2,2-dihydroxy-1,1’-binaphthyl (BINOL ), which has become one of the most utilized chiral ligand and auxiliary for diverse asymmetric syntheses. The unchallenged success of BINOL and its derivatives in the field of transition metal-catalyzed asymmetric reactions or C-C bond forming reactions promoted worldwide an advancement of organic synthesis. The first synthesis of BINOL as racemate was described in 1873. Since then there have been found numerous efficient methods of racemic or enantiomerically pure BINOL preparation and its derivatization. In order to present a brief overview of the most convenient and facile routes to obtain racemic and nonracemic symmetrically substituted 1,1’-binaphthyls based on stoichiometric and catalytic oxidative coupling, classical optical resolution, kinetic enzymatic resolution of racemic mixture or regioselective modification of the binaphthol scaffold the following article is presented.
Źródło:
Wiadomości Chemiczne; 2012, 66, 5-6; 485-528
0043-5104
2300-0295
Pojawia się w:
Wiadomości Chemiczne
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
2,2’-dihydroksy-1,1’-binaftyl (BINOL) i jego pochodne. Wybrane syntezy i zastosowanie. Część. II
2,2’-dihydroxy-1,1’-binaphthyl (BINOL) and its derivatives : selected synthesis methods and applications. Part II
Autorzy:
Krasowska, D.
Powiązania:
https://bibliotekanauki.pl/articles/172097.pdf
Data publikacji:
2013
Wydawca:
Polskie Towarzystwo Chemiczne
Tematy:
BINOL
atropoizomery
utleniające sprzęganie
enancjoselektywna synteza
chiralne ligandy
atropoisomers
oxidative coupling
optical resolution
enantioselective synthesis
chiral ligands
Opis:
An invention of new catalytic strategies for stereoselective synthesis is of current interest to many laboratories worldwide . Over the past few decades a remark - able progress in the field of stereocontrolled synthesis has been achieved with chiral 1,1’-binaphthyl compounds. Optically active 1,1’-binaphthyl-2,2’-diol (BINOL) and its derivatives due to their axial dissymmetry and molecular flexibility have been widely utilized as chiral ligands and auxiliaries in stoichiometric or catalytic asymmetric reactions, such as metal-catalysed transformations and enantioselective organocatalysis. BINOL and its functionalized analogues have demonstrated remark - able chiral discrimination properties. Extensive studies on molecular recognition provided the successful results in the application of BINOL as a host for an optical resolution of racemic guests and as a chiral NMR shift reagent for the determination of chiral compounds. It has been found that the axial chirality of binaphthyl units in host molecules is crucial contribution to their stereoselctive complexation with chiral guests.
Źródło:
Wiadomości Chemiczne; 2013, 67, 1-2; 55-92
0043-5104
2300-0295
Pojawia się w:
Wiadomości Chemiczne
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Influence of Co2 on the Catalytic Performance Of La2O3/CeO2 and CaO/CeO2 Catalysts in the Oxidative Coupling of Methane
Autorzy:
Litawa, B.
Michorczyk, P.
Ogonowski, J.
Powiązania:
https://bibliotekanauki.pl/articles/779348.pdf
Data publikacji:
2013
Wydawca:
Zachodniopomorski Uniwersytet Technologiczny w Szczecinie. Wydawnictwo Uczelniane ZUT w Szczecinie
Tematy:
CO2 effect
OCM
lanthanum oxide
calcium oxide
ethylene
Opis:
In this work the La2O3/CeO2 (33 mol % of La) and CaO/CeO2 (33 mol % of Ca) catalysts were prepared by the impregnation method and characterized by XRD and CO2-TPD. The catalytic properties of the catalysts were tested in the OCM process at 1073 K using the methane/oxygen mixture of the mole ratio 3.7 or 2.5 additionally containing CO2 and helium balance. It was found that in the presence of both catalysts an addition of CO2 enhances the selectivity to the ethylene and ethane and it does not have Any negative infl uence on methane conversion. In the case of the CaO/CeO2 catalyst the promoting effect of CO2 was the highest. When the partial pressure of CO2 equals to 39 kPa the increase in selectivity from 36 to 41% was noted while the conversion of methane equal to 19.4-19.7 %.
Źródło:
Polish Journal of Chemical Technology; 2013, 15, 1; 22-26
1509-8117
1899-4741
Pojawia się w:
Polish Journal of Chemical Technology
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Spectral correlations and antimicrobial activities of some (E)-N-Benzylidenepyridin-2-amines
Autorzy:
Sakthinathan, S. P.
Suresh, R.
Mala, V.
Sathiyamoorthi, K.
Kamalakkannan, D.
Ranganathan, K.
Arulkumaran, R.
Vijayakumar, S.
Sundararajan, R.
Vanangamudi, G.
Thirunarayanan, G.
Powiązania:
https://bibliotekanauki.pl/articles/412108.pdf
Data publikacji:
2013
Wydawca:
Przedsiębiorstwo Wydawnictw Naukowych Darwin / Scientific Publishing House DARWIN
Tematy:
Oxidative coupling Solvent-free synthesis
fly-ash
PTS
Aryl imines
IR and NMR spectra
Opis:
A series of aryl imines have been synthesized by Fly-ash: PTS catalyzed microwave assisted oxidative coupling of amines and aldehydes under solvent-free conditions. The yield of the imines has been found to be more than 90 %. The purity of all imines has been checked using their physical constants and spectral data as published earlier in literature. The UV ?maxC=N(nm), infrared ?C=N(cm-1), NMR ?(ppm) of CH=N and C=N spectral data have been correlated with Hammett substituent constants and F and R parameters using single and multi-linear regression analysis. From the results of statistical analysis, the effect of substituents on the above spectral data has been studied. The antimicrobial activities of all imines have been studied using Bauer-Kirby method.
Źródło:
International Letters of Chemistry, Physics and Astronomy; 2013, 6; 77-90
2299-3843
Pojawia się w:
International Letters of Chemistry, Physics and Astronomy
Dostawca treści:
Biblioteka Nauki
Artykuł
    Wyświetlanie 1-4 z 4

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