- Nickel-Catalyzed Decarboxylative Alkylation of Aryl Iodides with Anhydrides
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We present the anhydride-based decarboxylative alkylation of aryl iodides catalyzed by nickel. This method of decarboxylative coupling works with a broad scope of aliphatic carboxylic anhydrides and tolerates synthetically useful aromatic substituents. Assisted by a redox system of pyridine N-oxide and zinc additives, the current reaction occurs under mild conditions and without the assistance of photocatalyst. Notably, this method features high chemoselectivity toward alkyl migration with mixed aliphatic/aromatic anhydrides. Thus, it provides a powerful synthetic tool to modify high-valued aliphatic carboxylic acids by converting them into mixed anhydrides using readily available aryl carboxylic acids such as p-toluic acid. We propose a catalytic cycle that involves the key steps of free radical-based decarboxylation and subsequent alkyl transfer to nickel that precedes an oxidatively induced C-C reductive elimination from Ni(III).
- Chen, Hui,Hu, Lu,Ji, Wenzhi,Yao, Licheng,Liao, Xuebin
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p. 10479 - 10485
(2018/10/24)
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- Iron(III)-Catalyzed Ortho-Preferred Radical Nucleophilic Alkylation of Electron-Deficient Arenes
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The untraditional iron-catalyzed, ortho-preferred, radical alkylation of electron-deficient (hetero)arenes is reported. A variety of electron-deficient arenes were shown to react with various primary alkyl sources, producing the alkylated (hetero)arenes in good yields. This reaction might be an alkyl radical, nucleophilic aromatic substitution reaction, rather than the traditional electrophilic Friedel-Crafts reaction. HOMO-LUMO analysis and DFT studies on the key transition states underlying the regioselectivity are consistent with the observed reactions and the conclusions.
- Yu, Fei,Wang, Ting,Zhou, Huan,Li, Yajun,Zhang, Xinhao,Bao, Hongli
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supporting information
p. 6538 - 6541
(2017/12/26)
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- 4-ALKYL SUBSTITUTED PYRIDINES AS ODIFEROUS SUBSTANCES
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The present invention primarily concerns certain 4-alkyl pyridines of the following formula (I), wherein R is C8-C12 alkyl, odiferous substance mixtures and aromatic substance mixtures containing these 4-alkyl pyridines, the respective uses thereof as an odiferous or aromatic substance (mixture) and corresponding perfumed products.
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- Sunfish amphiphiles: Conceptually new carriers for DNA delivery
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A conceptually new class of cationic amphiphiles, Sunfish amphiphiles, designed for the delivery of genes into cells is introduced. Sunfish amphiphiles have two hydrophobic tails, connected at the 4- and the N-position to the cationic pyridinium headgroup. Two extreme morphologies visualised by backfolding and combining of both tails at one site (matching situation) or unfolding of the tails at distinct interaction sites at biological membranes will lead to considerable differences in morphological behaviour. The underlying rationale allows controlled release by using this morphological alteration of the Sunfish/helper-lipid/DNA complex (lipoplex). The often-excellent transfection efficiencies are probably related to these morphological changes. In addition, the Sunfish amphiphiles possess low toxicities, resulting in high cell survival after internalisation. The underlying rationale, design, synthesis and in vitro transfection potential are discussed in detail. Moreover, some physico-chemical characteristics of the Sunfish amphiphiles have been studied. Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004.
- Hulst, Ron,Muizebelt, Inouk,Oosting, Peter,Van Der Pol, Cornelia,Wagenaar, Anno,Smisterova, Jarmila,Bulten, Erna,Driessen, Cecile,Hoekstra, Dick,Engberts, Jan B. F. N.
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p. 835 - 849
(2007/10/03)
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- Antipruritic composition
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An antipruritic composition for an oral medicine, injection, and external medicine, comprising an effective amount of a chelated zinc (e.g., zinc picolinate) as an antipruritic agent.
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- Spectroscopic Differences between Molecular (O-H...N) and Ionic Pair (O(1-)...H-N(1+)) Hydrogen Complexes
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The centre of gravity () and chemical shifts (δH) of hydrogen-bonded protons in 55 complexes of pyridines with acetic acids have been measured in dichloromethane.If and δH are plotted against the aqueous pKa values for protonation of these bases general scatter diagrams are obtained which may be resolved into separate trends for different acids.We noted that this behaviour is controlled by the equilibrium between the molecular complex and the ion pair.Strong overlap of the carbonyl and carboxy stretching bands of the molecular complex and the hydrogen-bonded ion pair leads in most cases to a single band.Characteristic variations of the bandwidth were found.A plot of δH against can be resolved into a series of straight lines for molecular complexes, hydrogen-bonded ion pairs and their mixtures, respectively.A straight line for molecular complexes consists of data for the monomeric acids.The chemical shifts for N(1+)-H proton of the 'free' pyridine cation was estimated from the line of protonated pyridines and compared with the calculated value.
- Barczynski, Piotr,Dega-Szafran, Zofia,Szafran, Miroslaw
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p. 765 - 772
(2007/10/02)
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- ETUDE DES REACTIONS DE SUBSTITUTION HOMOLITIQUE SUR LE NOYAU PYRIDINIQUE; INFLUENCE DE L'ACIDITE DU MILIEU
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Homolytic substitution by the 1-n-undecyl radical at positions 2 and 4 of the pyridine nucleus results from thermal decomposition of dodecanoyl peroxide in acetic acid.Rate dependence on pH shows that pyridine protonation increases the rate of addition of the alkyl radical to the pyridine ring but decreases the rate of the reaction of the intermediate radical with the peroxide.Results are interpreted in terms of orbital interaction theory.
- Sebedio, J. L.,Sorba, J.,Fossey, J.,Lefort, D.
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p. 2829 - 2842
(2007/10/02)
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