نتایج جستجو برای: electrophilicity iindex

تعداد نتایج: 392  

Journal: :Zeitschrift fur Naturforschung. C, Journal of biosciences 2001
S Nishino T Kobayashi H Matsushima T Tokii Y Nishida

The binuclear zinc(II) complex, [Zn2(HPTP)(CH3COO)]2+ was found highly active to cleave DNA (double-strand super-coiled DNA, pBR322 and phix174) in the presence of hydrogen peroxide. However, no TBARS (2-thiobarbituric acid reactive substance) formation was detected in a solution containing 2-deoxyribose (or 2'-deoxyguanosine, etc); where (HPTP) represents N,N,N'-N'-tetrakis(2-pyridylmethyl)-1,...

Journal: :Organic letters 2007
Alexis D C Parenty Yu-Fei Song Craig J Richmond Leroy Cronin

A very simple annulation reaction was designed, allowing an imidazole moiety to be fused onto a range of pyridine-based derivatives. The methodology consists of an activation step via the formation of a pyridinium salt to increase the electrophilicity of the pyridine ring, followed by a cascade reaction triggered by a nucleophilic attack of the iminium moiety. Depending on the pyridinium salt, ...

2013
Bhawani Datt Joshi Poonam Tandon Sudha Jain

We have presented a study on structural conformation of yohimbine hydrochloride using density functional theory (DFT) method. A short description about the surface morphology with scanning electron microscopy imaging has been included. Correlation between different thermodynamic properties with variation in the temperature has been given. The global and local chemical reactivity descriptors hav...

Journal: :Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy 2002
Salim Y Hanna Moafaq Y Shandala Salim M Khalil

A series of 1-arylallyl alcohols were prepared and its OH stretching frequencies measured in 20 different non-HBD solvents at room temperature. It is noticed that the observed stretching bands were highly sensitive to the nature of the solvents. Multiple parameter equations were applied to investigate the solvent effects on the O-H stretching frequency. The most significant solvent parameters w...

2017
Guo-Xing Li Cristian A. Morales-Rivera Fang Gao Yaxin Wang Gang He Peng Liu Gong Chen

We report a unified photoredox-catalysis strategy for both hydroxylation and amidation of tertiary and benzylic C–H bonds. Use of hydroxyl perfluorobenziodoxole (PFBl–OH) oxidant is critical for efficient tertiary C–H functionalization, likely due to the enhanced electrophilicity of the benziodoxole radical. Benzylic methylene C–H bonds can be hydroxylated or amidated using unmodified hydroxyl ...

Journal: :The journal of physical chemistry. A 2003
Eduardo Chamorro Pratim K Chattaraj Patricio Fuentealba

Some exact conditions for the extremals of the electrophilicity index, ω = μ(2)/2η (Parr, R. G.; von Szentpály, L.; Liu, S. J. Am. Chem. Soc. 1999, 121, 1922), along an arbitrary reaction coordinate, have been carefully examined. Implications within the widely used finite difference approximation for the density-functional based reactivity descriptors, their relationship with the maximum hardne...

2016
Norihiro Tada Daniel J. Jansen Matthew P. Mower Megan M. Blewett Jeffrey C. Umotoy Benjamin F. Cravatt Dennis W. Wolan Ryan A. Shenvi

We describe a general method to synthesize the iminium tetrahydrothiophene embedded in the dimeric Nuphar alkaloids. In contrast to prior studies, the sulfur atom of the thiaspirane pharmacophore is shown to be electrophilic. This α-thioether reacts with thiophenol or glutathione at ambient temperature to cleave the C-S bond and form a disulfide. Rates of conversion are proportional to the corr...

Journal: :Journal of the Turkish Chemical Society, Section A: Chemistry 2016

Journal: :Chemical communications 2011
Sami Lakhdar Herbert Mayr

Electrophilic substitution of pyrroles by α,β-unsaturated iminium ions is slow in acetonitrile when only weakly basic counterions are present. When the reactions are carried out in the presence of KCF(3)CO(2), fast deprotonation of the intermediate σ-adducts occurs, and the rate constant for the rate-determining CC bond-forming step can be predicted from the electrophilicity parameter E of the ...

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