نتایج جستجو برای: stereoelectronic effect

تعداد نتایج: 1641819  

Journal: :Organic & biomolecular chemistry 2016
Martina L Contente Immacolata Serra Luca Palazzolo Chiara Parravicini Elisabetta Gianazza Ivano Eberini Andrea Pinto Benedetta Guidi Francesco Molinari Diego Romano

A recombinant ketoreductase from Pichia glucozyma (KRED1-Pglu) was used for the enantioselective reduction of various mono-substituted acetophenones. Reaction rates of meta- and para-derivatives were consistent with the electronic effects described by σ-Hammett coefficients; on the other hand, enantioselectivity was determined by an opposite orientation of the substrate in the binding pocket. R...

Journal: :Molecules 2013
Maria E Amato Francesco P Ballistreri Andrea Pappalardo Gaetano A Tomaselli Rosa M Toscano Giuseppe Trusso Sfrazzetto

We have investigated the oxidative behaviour of natural compounds such as methyl abietate (1), farnesyl acetate (2), α-ionone (3), β-ionone (4), methyl linolelaidate (5), methyl linolenate (6) and bergamottin (7) with the oxidant system methyltrioxo-rhenium/ H2O2/pyridine. The reactions, performed in CH2Cl2/H2O at 25 °C, have shown good regio- and stereoselectivity. The oxidation products were ...

Journal: :Acta Crystallographica Section A Foundations of Crystallography 2011

2006
Mar Sabaté Amadeu Llebaria Antonio Delgado

The reaction course of the selenation-oxidation-elimination sequence carried out from cis-4-benzyloxy-1,2-epoxycyclohexane (cis-1) is studied. Contrary to literature precedents, this transformation leads to an unexpected diastereomeric cyclohexenol, whose formation can be interpreted by stereoelectronic grounds. In addition, the base induced rearrangement of cis-1 with lithium amide bases is al...

Journal: :Anais da Academia Brasileira de Ciencias 2016
Raquel R S Salvador Murilo L Bello Igor R L Barreto Maria A F Vera Estela M F Muri Sérgio DE Albuquerque Luiza R S Dias

This paper reports the in vitro trypanocidal activity evaluation of new carbohydrazide derivatives from 3-methyl-1-phenyl-1H-pyrazolo[3,4-b]pyridine, substituted at C-6 position by phenyl, methyl or trifluoromethyl group. These compounds were evaluated in order to identify the antiparasitic profile against trypomastigote and amastigote forms of Trypanosoma cruzi. The 4-carbohydrazide derivative...

2012
Fátima M P de Rezende Marilua A Moreira Rodrigo A Cormanich Matheus P Freitas

Four diastereoisomers of 2-fluorobicyclo[2.2.1]heptan-7-ols were computationally investigated by using quantum-chemical calculations, and their relative energies were analyzed on the basis of stereoelectronic interactions, particularly the presence or otherwise of the F∙∙∙HO intramolecular hydrogen bond in the syn-exo isomer. It was found through NBO and AIM analyses that such an interaction co...

Journal: :Organic & biomolecular chemistry 2015
Masoud Samet Alireza Fattahi Steven R Kass

Different strategies are employed in designing strong and selective anion receptors but stereoelectronic effects have been largely ignored. In this work, the stereo configuration of a non-interacting ether is found to have a large impact of more than two orders of magnitude on the binding of a rigid diol with tetrabutylammonium chloride in acetonitrile-d3. A favorable carbon-oxygen dipole and a...

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