نتایج جستجو برای: electron withdrawing

تعداد نتایج: 310077  

Journal: :Chemical & pharmaceutical bulletin 2001
R Fujita K Watanabe T Yoshisuji C Kabuto H Matsuzaki H Hongo

Diels-Alder cycloadditions of 2(1H)-quinolones having an electron-withdrawing group at the 3-position with alkyl- and silyloxy-1,3-butadienes (2a,b) were carried out to give phenanthridones richly functionalized regio- or stereoselectively under conditions of atmospheric and high pressure. Furthermore, regioselectivity and chemoselectivity of 3-substituted 2(1H)-quinolones to 2a, b were examine...

Journal: :Physical chemistry chemical physics : PCCP 2010
Tadeusz M Krygowski Wojciech P Oziminski Marcin Palusiak Patrick W Fowler Andrew D McKenzie

Fulvene is a non-aromatic molecule, but variation of the electron-donating/withdrawing power of substituents exo to the five-membered ring can drive the system between the extremes of aromatic and antiaromatic, as judged by prediction of fully developed diatropic and paratropic ring currents through ab initio calculations made at the ipsocentric 6-31G**/CTOCD-DZ CHF level.

2013
Adam Trawczyński Robert Bujok Zbigniew Wróbel Krzysztof Wojciechowski

Alkylation of 5-nitroindol-4-ylacetonitriles with ethyl chloroacetate, α-halomethyl ketones, and chloroacetonitrile followed by a treatment of the products with chlorotrimethylsilane in the presence of DBU gives 1-cyanopyrrolo[3,2-e]indoles substituted in position 2 with electron-withdrawing groups.

Journal: :Chemical communications 2015
Min Zhou Wei Li Tiantian Gu Kangli Wang Shijie Cheng Kai Jiang

A Na-rich cathode is developed by grafting the electron-withdrawing -SO3Na group on polyaniline chains. Due to the immobile doping and effective activation of the sulfonate group, this polymer demonstrates a high capacity (133 mA h g(-1)) and excellent cyclability through a cation-exchange reaction, offering a low cost and sustainable cathode for SIBs.

Journal: :Organic & biomolecular chemistry 2014
Hassen Bel Abed Oscar Mammoliti Omprakash Bande Guy Van Lommen Piet Herdewijn

The elaboration of the first organophosphorus-catalyzed diaza-Wittig reaction is reported. This catalytic reaction is applied to the synthesis of substituted pyridazine and phthalazine derivatives bearing electron-withdrawing groups with good to excellent yields from substrates containing a diazo functionality as the starting material and a phospholene oxide as the catalyst.

2011
Ameer F Zahoor Sarah Thies Uli Kazmaier

Complex amino acids with an α-acyloxycarbonyl functionality in the side chain are easily available through epoxide opening by chelated enolates and subsequent oxidation/Passerini reaction. This protocol works with both, aldehyde and ketone intermediates, as long as the ketones are activated by electron-withdrawing groups. In principle Ugi reactions are also possible, allowing the generation of ...

Journal: :Chemical & pharmaceutical bulletin 2001
R Fujita K Watanabe T Yoshisuji H Matsuzaki Y Harigaya H Hongo

Diels-Alder reactions of 2(1H)-quinolones having an electron-withdrawing group at the 4-position with 1,3-butadiene derivatives were carried out to give the phenanthridones richly functionalized under the conditions of atmospheric and high pressure. Furthermore, the reactivities of 4-substituted 2(1H)-quinolones acting as a dienophile were examined using MO calculation.

Journal: :iranian chemical communication 2015
seyyedeh cobra azimi kurosh rad-moghadam

a homogeneous ionic liquid 1-butyl-3-methylimidazolium tetrafluoroborate doped with licl ([bmim]bf4-licl) was found as catalyst solvents for the synthesis of dicoumarols by the condensation of 4-hydroxycoumarin and aldehyde at 80 ˚c. in this field, several types of aromatic aldehyde, containing electron-withdrawing groups as well as electron-donating groups, were rapidly changed to the correspo...

2005
Sharon R. SPENCER Liang XUE Elizabeth M. KLENZ Paul TALALAY

Induction of glutathione transferases (EC. 2.5.1.18), NAD(P)H: (quinone-acceptor) oxidoreductase (EC 1.6.99.2; quinone reductase) and other detoxification enzymes is a major mechanism for protecting cells against the toxicities of electrophiles, including many carcinogens. Although inducers of these two enzymes belong to many different chemical classes, they nevertheless contain (or acquire by ...

Journal: :Chemical communications 2010
Adam J V Marwitz Sean P McClintock Lev N Zakharov Shih-Yuan Liu

BN Benzonitrile 2, a 1,2-dihydro-1,2-azaborine bearing an electron-withdrawing boron substituent was prepared and characterized, and its coordination chemistry investigated; reactivity studies revealed that BN benzonitrile 2 undergoes BCN-BNC linkage isomerism upon coordination to Cr(CO)(5).

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