- Air-stable nickel precatalysts for fast and quantitative cross-coupling of aryl sulfamates with aryl neopentylglycolboronates at room temperature
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A library containing 10 air-stable NiIIX(Aryl)(PCy3)2 complexes as precatalysts (X = Cl, Br, OTs, OMs, aryl = 1-naphthyl, 2-naphthyl; X = Cl, 1-acenaphthenyl, 1-(2-methoxynaphthyl), 9-phenanthrenyl, 9-anthracyl) was synthesized and demonstrated to quantitatively cross-couple 2-methoxyphenyl dimethylsulfamate with methyl 4-(5,5-dimethyl-1,3,2-dioxaborinane-2-yl)benzoate at 23 °C in dry THF in the presence of K3PO4(H2O)3.2 in less than 60 min. Lower or higher amounts of H2O in K3PO4 and as received THF mediate the same transformation in a maximum three times longer reaction time.
- Jezorek, Ryan L.,Zhang, Na,Leowanawat, Pawaret,Bunner, Matthew H.,Gutsche, Nicholas,Pesti, Aleksander K. R.,Olsen, James T.,Percec, Virgil
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supporting information
p. 6326 - 6329
(2015/02/19)
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- Light-induced carbocyclization of iodoalkenes
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The direct irradiation of iodoalkenes leads to the formation of carbon-centered radical by homolysis of the C-I bond. The photoreaction is used in cyclizations with formation of six membered rings.
- Campos-Gómez, Esther,Campos, Pedro J.,González, Héctor F.,Rodríguez, Miguel A.
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p. 4292 - 4295
(2012/07/16)
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- Nucleophilic substitution of hydrogen in naphthalene by chloride (Cl -) in ionic liquids
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Nucleophilic aromatic substitution of hydrogen in non-activated aromatic ring, a very rare phenomenon in organic chemistry, is found in ionic liquids containing Cl- as anion under mild reaction conditions. The reaction may be carried out by the addition of the halogen-bonding adduct (Br 2Cl-) as nucleophile to aromatic ring carbon atom, leading to the formation of the nucleophilic substitution product.
- Shi, Shen Yi,Kong, Ai Guo,Zhao, Xin Hua,Ding, Han Ming,Yang, Fan,Shan, Yong Kui
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experimental part
p. 147 - 150
(2012/01/03)
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- Behavior and prediction of photochemical degradation of chlorinated polycyclic aromatic hydrocarbons in cyclohexane
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The photochemical degradation of 11 chlorinated polycyclic aromatic hydrocarbons (ClPAHs) and the corresponding 5 parent PAHs was examined to simulate the compound's fate on aerosol surfaces. All the ClPAHs and PAHs decayed according to the first-order reaction rate kinetics. The photolysis rates of ClPAHs varied greatly according to the skeleton of PAHs; the rates of chlorophenanthrenes (ClPhes) and 1-chloropyrene were higher than those of corresponding parent PAHs, whereas chlorofluoranthenes, 7-chlorobenz[a]anthracene and 6-chlorobenzo[a]pyrene were more stable under irradiation compared to respective parent PAH. Considering the photoproducts of ClPhes detected, the oxidation could occur immediately at positions of the highest frontier electron density. Finally, the quantitative structure-property relationship models were developed for direct photolysis half-lives and average quantum yields of the ClPAHs and parent PAHs, in which the significant factors affecting photolysis were ELUMO+1, total energy and surface area, and ELUMO, ELUMO - EHOMO and total energy, respectively.
- Ohura, Takeshi,Amagai, Takashi,Makino, Masakazu
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p. 2110 - 2117
(2008/09/19)
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- A novel application of the Diels-Alder reaction: nitronaphthalenes as normal electron demand dienophiles
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Thermal reactions between nitronaphthalenes and butadienes were studied. It was demonstrated that these reactions are capable of undergoing the normal electron demand Diels-Alder reaction, with a variety of dienes affording the phenanthrene derivatives. The influence of the extension and type of substitution was also discussed. When the electron-withdrawing activation of the naphthalenic nucleus or the donor properties of the dienes were not enough, N-naphthylpyrroles were detected as main product, suggesting that a competitive reaction would probably take place. The results clearly confirmed the dienophilic nature of nitronaphthalenic double bonds and provided an alternative procedure for phenanthrene derivatives and N-naphthylpyrroles' synthesis. The relative reactivity of the reactants and the viability of the reactions were discussed from a theoretical point of view.
- Paredes, Elisa,Brasca, Romina,Kneeteman, María,Mancini, Pedro M.E.
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p. 3790 - 3799
(2008/02/01)
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- Oxidative halogenation of aromatic compounds with metal halides and sodium bismuthate
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A new mild and efficient method for aromatic halogenation with a wide variety of halides in the presence of sodium bismuthate NaBO3 in AcOH is reported. Metal halides of groups Ia, IIa, IIIa, IVa, Va, and the first row of transition elements are suitable for this method.
- Muathen, Hussni A.
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p. 164 - 168
(2007/10/03)
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- Analysis and structure prediction of chlorinated polycyclic aromatic hydrocarbons released from combustion of polyvinylchloride
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Chlorinated polycyclic aromatic hydrocarbons (Cl-PAHs) released from combustion of polyvinylchloride (PVC) at different furnace temperatures were investigated. A laboratory-scale tube-type furnace with electric heating was utilized to control combustion conditions. Glass fabric filters and adsorbents were used to collect the combustion emissions. Following Soxhlet extraction, concentration and column chromatography purification, isomers separation, selective detection and identification of Cl-PAHs were performed on GC/MS system on the basis of retention data and mass spectra. Their quantification was accomplished by using external standard calibration technique. About 18 Cl-PAHs were determined, most of which were monochlorinated derivatives of naphthalene, biphenyl, fluorene, phenanthrene, anthracene, fluoranthene and pyrene. Only two dichlorophenanthrenes or anthracenes were identified. The possible positions of chlorine atoms attached to the aromatic rings are predicted by quantitative structure-property relationship. The levels of these compounds were in the range of 0.30-29.08 μg/g PVC. The relationship between the formation of Cl-PAHs and PAHs was discussed.
- Wang, Dongli,Xu, Xiaobai,Chu, Shaogang,Zhang, Daren
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p. 495 - 503
(2007/10/03)
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- Iodination and chlorination of aromatic polycyclic hydrocarbons with iodine monochloride in aqueous sulfuric acid
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Polycyclic aromatic hydrocarbons when treated with iodine monochloride in water solutions of sulfuric acid afford iodo-and chloroderivatives. Biphenyl, fluorene, acenaphthene, 1-nitronaphthalene undergo iodination. Naphthalene furnishes a mixture of iodo-and chloroderivatives, prevailing the latter. Anthracene and phenanthrene provide only chlorinated products. The iodine monochloride in the sulfuric acid is a stronger iodinating agent than in acetonitrile.
- Chaikovskii,Filimonov
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p. 1130 - 1133
(2007/10/03)
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- Unexpected high temperature behaviour of 2,2′-diethynylbiphenyl in the gas phase - A precursor for acephenanthrylene instead of pyrene
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Flash Vacuum Thermolysis (FVT) of 2,2′-diethynylbiphenyl (6) gave, instead of pyrene (5), acephenanthrylene (10) and fluoranthene (11) as major products. The unequivocal identification of 9-ethynylphenanthrene (12) at T ≤ 800°C suggests that 12 is the initial stable product derived from 6. It is documented that under high-temperature conditions in the gas phase compound 12 is efficiently converted into 10, which subsequently rearranges to 11. The formation of 12 from 6 is rationalized by invoking the transient formation of cyclobuta[l]phenanthrene (13) by intramolecular cyclization of the ethynyl moieties of 6 followed by a reiro-carbene C-H insertion and a 1,2-H shift. This interpretation is supported by the results of independent FVT of 2,2′-bis(1-chloroethenyl)biphenyl (15). Wiley-VCH Verlag GmbH, 1997.
- Sarobe, Martin,Van Heerbeek, Rieko,Jenneskens, Leonardus W.,Zwikker, Jan W.
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p. 2499 - 2503
(2007/10/03)
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- Mild chlorination of aromatic compounds with tin(IV) chloride and lead tetraacetate
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SnCl4/Pb(OAc)4 acts as a safe source of Cl2 for the chlorination of aromatic compounds. A variety of aromatic compounds are effectively chlorinated with SnCl4/Pb(OAc)4 under mild conditions. The mixture is a selective chlorinating agent, particularly with polyalkylbenzenes, polycyclic aromatic compounds and anisoles.
- Muathen, Hussni A.
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p. 8863 - 8866
(2007/10/03)
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- Electronic and Conformational Effects in the Photochemistry of α-Alkenyl-Substituted Vinyl Halides
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The photochemical reactions in methanol of the vinylic halides 2-halo-1-phenyl-1,3-butadienes 1-3Z-X (β-halo-β-alkenylstyrenes) and 1-halo-1,2-diphenylethenes 4Z-X (α-halostilbenes), with X = Cl or Br, have been studied quantitatively.E/Z isomerization, dehydrohalogenation, nucleophilic substitution, a -halogen shift, a -hydrogen shift, and oxidation are observed as the primary reactions.No reductive dehalogenation products are formed.The efficiencies of product formation are dependent on the halogen used, the electron-donating capacity of the α-substituent, the ground state conformation of the starting material, and the wavelength of excitation.Apart from the photoinduced E/Z isomerization and the oxidation reaction typical for alkenes, product formation occurs exclusively via vinyl-cationic intermediates, which are formed upon photolytic cleavage of the carbon-halogen bond.These ionic species, or part of them, are present as vinyl cation/halide anion-pairs.
- Krijnen, Erik S.,Zuilhof, Han,Lodder, Gerrit
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p. 8139 - 8150
(2007/10/02)
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- The Reaction of Iodine Monochloride with Polycyclic Aromatic Compounds: Polar and Electron Transfer Pathways
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Several polycyclic aromatic hydrocarbons were treated with iodine monochloride.Although iodination is the predominant reaction of benzenoid arenes, chlorination is the sole reaction with anthracene, phenanthrene and naphthalene compounds (except for 5), whose oxidation half-wave potentials are less than 1.58 V vs Ag/Ag(+) (0.1 M).Arenes with higher potentials are unreactive.Naphthalene (9) and its derivatives with mild electron-withdrawing substituents are chlorinated; the exception (5) yields the 1-iodo product (21).The reaction is first order in substrate and second order in ICl.An electron transfer pathway involving radical cation intermediates is assumed.Ion-pair collapse of the radical cation-ICl intermediates is proposed for the chlorinations and radical-pair collapse for the iodination.
- Turner, Dean E.,O'Malley, Robert F.,Sardella, Dennis J.,Barinelli, Lucio S.,Kaul, Pushkar
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p. 7335 - 7340
(2007/10/02)
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- Generation of 2-Substituted 1-Ethenyl Cations from Ethylenediazonium Salts
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Thermal decomposition of 2-substituted ethylenediazonium salts 1a-d produces the corresponding 1-ethenyl cations 2a-d as short-lived intermediates.The primary vinyl cation 2d or the rearranged and energetically favored analogues 3a-c of 2a-c are intercepted by chloride to give the decomposition products 4d and 5a-c, respectively.The generation of 4d and 5a-c as well as a kinetic study of the thermolysis reaction provide no indication that the elimination of nitrogen from 1a-d is occurring with the intermediate formation of cyclic cations 6 or 7. - Key Words: Ethylenediazonium salts, thermal stability of, thermal degradation of / Ethenyl cations, generation of, rearrangement of, interception of / Kinetics
- Bott, Kaspar
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p. 933 - 940
(2007/10/02)
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- On the Acetylation of Phenanthrene and 9-Chlorphenanthrene
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Friedel-Crafts acetylation of phenanthrene (1a) in sym-tetrachlorethane yields mixtures of 2-,3- and 9-acetylphenanthrenes (2a,3a,4).The distribution of isomers is found to depend strongly upon the method of mixing the reagents.Acetylation of 9-chlorophenanthrene (1b), perfomed by a variety of methods and solvents, led mainly to 3-acetyl-9-chlorophenanthrene (3b) (>/=85percent).Previously unreported 2-acetyl-9-chlorophenanthrene (2b) was found to form up to a maximum 11percent in nitrobenzene.
- Fernandez, Franco,Gomez, Generosa,Lopez, Carmen,Santos, Ana
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- The Chemistry of Arene Imines. IV. An Unusual Silver Promoted Transformation of N-Chlorophenanthrene 9,10-Imine into 9,10-Phenanthrenequinone Dialkyl Acetals
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Methanolic silver nitrate and perchlorate convert N-chlorophenanthrene 9,10-imine (1) into 10,10-dimethoxy-9(10H)-phenanthrone (2) in 60percent yield.Substitution of the methanol by ethanol, 1- and 2-propanol gives phenanthrenequinone diethyl-, di-1-propyl- and di-2-propylacetals (3-5), respectively.Silver acetate promotes these transformations only in the presence of a protic acid.The reaction mechanism is assumed to involve the generation of a cyclic nitrenium ion, nucleophilic ring opening by methanol, hydrolysis of the imine function and silver ion promoted oxidation.
- Shtelzer, Sarah,Sheradsky, Tuvia,Blum, Jochanan,Zitrin, Shmuel
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p. 1593 - 1595
(2007/10/02)
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- Reactions of Phenanthrenes with Nitrogendioxid in UV Light
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The compounds 2-7 were isolated from solutions of phenanthrene (1) and nitrogendioxide in carbon tetrachloride after irradiation with UV light having long wavelengths (λ > 290 nm).With the help of spectroscopical methods the proposed structures are derived.Radical mechanisms are proposed for these reactions. - Key words: Phenanthrene, Nitrogendioxid, UV Light
- Barlas, H.,Parlar, H.,Kotzias, D.,Korte, F.
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p. 486 - 489
(2007/10/02)
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- SURFACE PHOTOCHEMISTRY: THE PHOTO-CHLORINATION OF AROMATIC HYDROCARBONS WITH FERRIC CHLORIDE ON ALUMINA
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Irradiation of a number of aromatic hydrocarbons adsorbed on alumina in the presence of ferric chloride leads to monochlorination.
- Hasebe, Masato,Lazare, Catherine,Mayo, Paul de,Weedon, Alan C.
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p. 5149 - 5152
(2007/10/02)
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