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Synthesis of thioacrolein S-oxide and thioketene S-oxide using FVT
FVT was used to synthesize thioacrolein S-oxide and thioketene S-oxide. These reactive species were characterized at low temperature by IR and/or NMR spectroscopies.
Minassian, Frederic,Levillain, Jocelyne,Pelloux-Leon, Nadia,Ripoll, Jean-Louis,Vallee, Yannick
p. 335 - 336
(1999)
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Substituted 9-Anthraldehydes from Dibenzocycloheptanol Epoxides via Acid-Catalyzed Epoxide Opening/Semipinacol Rearrangement
Starting from benzaldehyde derivatives, the corresponding dibenzocycloheptenol could be prepared in five steps. Under both substrate (secondary vs tertiary alcohol and the substituents on the aromatic ring(s)) and condition control, the subsequent epoxidation and acid-catalyzed epoxide opening/semipinacol rearrangement/aromatization afforded the corresponding 9-anthraldehydes in good yields, up to 88% over two steps. The presence of the electron-withdrawing group(s) on the aromatic ring(s) suppressed the rate of the epoxidation while the subsequent semipinacol rearrangement step required heating; the presence of the electron-donating group(s), on the other hand, frequently led to the decomposition during the epoxidation. From the mechanistic studies, the semipinacol rearrangement of the epoxide could precede the ionization at the bisbenzylic position, yielding the aldehyde intermediate. The ensuing dehydrative aromatization led to the formation of 9-anthraldehyde. Conversely, nucleophilic addition to the aldehyde and dehydrative aromatization with concomitant loss of formic acid led to anthracene.
Phumjan, Tanawat,Songthammawat, Poramate,Jongcharoenkamol, Jira,Batsomboon, Paratchata,Ruchirawat, Somsak,Ploypradith, Poonsakdi
p. 13322 - 13349
(2021/09/13)

1,4-Dehydrogenation with a Two-Coordinate Cyclic (Alkyl)(amino)silylene
Cyclic (alkyl)(amino)silylene (CAASi) 1 has been found to successfully dehydrogenate 1,4-dihydroaromatic compounds containing various substituents to afford the corresponding aromatic compounds. The observed high substrate generality proves 1 to be a potential 1,4-dehydrogenation reagent for organic compounds. For the reaction with 9,10-dimethyl-9,10-dihydroanthracene, silylene 1 activated not only benzylic C?H bonds but also aromatic C?H bonds to yield a silaacenaphthene derivative, which is an unprecedented reaction of silylenes. The results of the experimental and computational study of the reaction of CAASi 1 with 9,10-dihydroanthracene and 1,4-cyclohexadiene are consistent with the notion that 1,4-dehydrogenation with CAASi 1 proceeds mainly through a stepwise hydrogen-abstraction mechanism.
Koike, Taichi,Kosai, Tomoyuki,Iwamoto, Takeaki
supporting information
p. 9295 - 9302
(2019/07/04)

Features of the Diels-Alder reaction between 9,10-diphenylanthracene and 4-phenyl-1,2,4-triazoline-3,5-dione
The Diels-Alder reaction between substituted anthracenes 1a-1j and 4-phenyl-1,2,4-triazoline-3,5 (2) is studied. In all cases except one, the reaction proceeds on the most active 9,10-atoms of substituted anthracenes. The orthogonality of the two phenyl groups at the 9,10-position of diene 1a is found to shield 9,10-reactive centers. No dienophiles with C=C bonds are shown to participate in the Diels-Alder reaction with 1a; however, the reaction 1a + 2 proceeds with the very active dienophile 2,4-phenyl-1,2,4-triazoline-3,5-dione. It is shown that attachment occurs on the less active but sterically accessible 1,4-reactive center of diene 1a. The structure of adduct 3a is proved by 1H and 13C NMR spectroscopy and X-ray diffraction analysis. The following parameters are obtained for reaction 1a + 2 ? 3a in toluene at 25°C: Keq = 2120 M-1, ΔHf≠ = 58.6 kJ/mol, ΔSf≠ = -97 J/(mol K), ΔVf≠ = -17.2 cm3/mol, ΔHb ≠ = 108.8 kJ/mol, ΔSb≠ = 7.3 J/(mol K), ΔVb≠ = -0.8 cm3/mol, ΔHr-n = -50.2 kJ/mol, ΔSr-n = -104.3 J/(mol K), ΔVr-n = -15.6 cm3/mol. It is concluded that the values of equilibrium constants of the reactions 1a-1j + 2 ? 3a-3j vary within 4 × 101-1011 M-1.
Kiselev,Kornilov,Kashaeva,Potapova,Krivolapov,Litvinov,Konovalov
p. 2073 - 2080
(2015/02/19)

Cobalt-catalyzed branched-selective addition of aromatic ketimines to styrenes under room-temperature conditions
An improved cobalt-based catalytic system has been developed for the branched-selective addition of aromatic ketimines to styrenes. With an appropriate combination of triarylphosphine and the Grignard reagent, the reaction takes place smoothly at room temperature to afford 1,1-diarylethane derivatives with high regioselectivity.
Dong, Jinghua,Lee, Pin-Sheng,Yoshikai, Naohiko
supporting information
p. 1140 - 1142
(2013/10/22)

Dynamic Covalent chemistry: A facile room-temperature, reversible, diels-alder reaction between anthracene derivatives and n-phenyltriazolinedione
A series of readily accessible, dynamic Diels-Alder reactions that are reversible at room temperature have been developed between anthracene derivatives as dienes and N-phenyl-1,2,4-triazoline-3,5-dione as the dienophile. The adducts formed undergo reversible component exchange to form dynamic libraries of equilibrating cycloadducts. Furthermore, reversible adduct formation allows temperature-dependent modulation of the fluorescent properties of anthracene components; a feature of potential interest for the design of optodynamic polymeric materials by careful selection and manipulation of these simple dienes and dienophiles. Copyright
Roy, Nabarun,Lehn, Jean-Marie
p. 2419 - 2425
(2012/07/03)

Photogeneration and reactivity of acyl nitroso compounds
Acyl nitroso compounds have been generated by photolysis of several different classes of precursors including 9,10-dimethylanthracene adducts, nitrodiazo compounds, and 1,2,4-oxadiazole-4-oxides. Consideration of the nitronate-like resonance structure of nitrodiazo compounds led to an examination of the photochemistry of nitronates with -leaving groups. Photolysis of such nitronates has been shown to generate an acyl nitroso species along with a carbene intermediate. Nanosecond time-resolved infrared (TRIR) spectroscopy has been used to detect photogenerated acyl nitroso compounds directly and to examine their reaction kinetics with amines and thiols. The mechanism of acyl nitroso aminolysis by primary amines involves general base catalysis, while the mechanism of aminolysis by secondary amines is strictly bimolecular. Thiols do not seem to be reactive with acyl nitroso compounds on the microsecond time scale, but thiolates are quite reactive. The reaction between benzoyl nitroside and an organic-soluble thiolate, tetrabutylammonium dodecanethiolate, proceeds via a proposed tetrahedral intermediate, which is observable by TRIR spectroscopy.
Evans, Anthony S.,Cohen, Andrew D.,Gurard-Levin, Zachary A.,Kebede, Naod,Celius, Tevye C.,Miceli, Alexander P.,Toscano, John P.
scheme or table
p. 130 - 138
(2011/04/23)

Low temperature Kumada-Corriu cross-coupling of polychlorinated acene derivatives and a synthesis of sterically demanding acenes
Conditions for low-temperature Kumada-Corriu cross-coupling of polychlorinated acenes with Grignard reagents are reported. Our work was motivated by a search for cross-coupling reactions effective in the synthesis of functionalized linear acenes for organic materials applications. Treatment of polychlorinated acenes with the PEPPSI-IPr catalyst and MeMgBr undergo 6-8 concurrent coupling reactions to yield products such as octamethylnaphthalene, which is distorted out of planarity due to the steric interaction between the methyl groups. More sterically demanding Grignard reagents such as PhMgBr coupled cleanly with 9,10-dichloroanthracene to provide products such as 9,10-diphenylanthracene, a blue OLED component, in excellent yield.
Yagodkin, Elisey,Douglas, Christopher J.
supporting information; experimental part
p. 3037 - 3040
(2010/07/18)

X-ray structure of a CT complex relevant to Diels-Alder reactivity of anthracenes
(Chemical Equation Presented) Combining the results of thermodynamic and kinetic investigations with an X-ray characterization of a transient CT complex sheds more light on the Diels-Alder reactivity of a strongly electron-deficient olefin, namely the 4-n
Berionni, Guillaume,Bertelle, Pierre-Alexandre,Marrot, Jerome,Goumont, Regis
scheme or table
p. 18224 - 18225
(2010/04/24)

Photoactivatable HNO-releasing compounds using the retro-Diels-Alder reaction
We synthesized hetero-Diels-Alder cycloadducts from acyl nitroso derivatives and 9,10-dimethylanthracene, to be photo-inducible HNO-releasing agents and found that introduction of conjugated nitroaromatic groups effectively enhanced the responsiveness of HNO release to UV-A irradiation; we confirmed photoinduced HNO formation by EPR and GCMS analysis. The Royal Society of Chemistry.
Adachi, Yusuke,Nakagawa, Hidehiko,Matsuo, Kazuya,Suzuki, Takayoshi,Miyata, Naoki
supporting information; experimental part
p. 5149 - 5151
(2009/03/11)

Complementarity in bimolecular photochromism
Irradiating 2,3,6,7-tetraphenylanthracene in the presence of 9,10-dimethylanthracene leads to exclusive formation of the cross-dimer. No photochemical reaction is observed when either of these chromophores is irradiated in the absence of the other. The Roval Society of Chemistry 2005.
Bailey, David,Williams, Vance E.
p. 2569 - 2571
(2007/10/03)

Nitroxyl (HNO) release from new functionalized N-hydroxyurea-derived acyl nitroso-9,10-dimethylanthracene cycloadducts
A thermal retro-Diels-Alder decomposition of N-hydroxyurea-derived acyl nitroso compounds and 9,10-dimethylanthracene cycloadducts followed by acyl nitroso compound hydrolysis produces nitrous oxide, evidence for the formation of nitroxyl, the one-electron reduced form of nitric oxide that has drawn considerable attention for its potential roles in biological systems. EPR and NMR spectroscopy provide further evidence for nitroxyl formation and kinetic information, respectively. Such compounds may prove to be useful alternative nitroxyl donors.
Zeng, Bu-Bing,Huang, Jinming,Wright, Marcus W.,King, S. Bruce
p. 5565 - 5568
(2007/10/03)

Flow-vacuum pyrolysis of polycyclic compounds. 171 pyrolysis of 2-mETHYL-cis-9, 10-bis(hydroxymethyl)-9,10-dihydroanthracene
The flow-vacuum pyrolysis of 2-methyl-cis-9,10-bis(hydroxymethyl)-9,10-dihydroanthracene (6) was studied by GC/MS at 1.33 mbar in argon atmosphere between 500°C and 650°C. The major reaction products were: 2-methyl-9,10-dihydroanthracene (19) and 2-methylanthracene (15), the minor products being 9,10-dimethylanthracene (20) and probably one of its positional isomers. Increasing the pyrolysis temperature produces the conversion of 19 into 15. The thermal behavior of 6 was rationalized on the basis of a radical mechanism.
Banciu, Anca,Parvulescu, Luminitza,Popescu, Angela,Ciuculescu, Diana,Banciu, Mircea D.
p. 407 - 412
(2007/10/03)

Photocatalytic oxygenation of anthracenes and olefins with dioxygen via selective radical coupling using 9-mesityl-10-methylacridinium ion as an effective electron-transfer photocatalyst
Visible light irradiation of the absorption band of 9-mesityl-10- methylacridinium ion (Acr+-Mes) in an O2-saturated acetonitrile (MeCN) solution containing 9,10-dimethylanthracene results in formation of oxygenation product, i.e., dimethylepidioxyanthracene (Me 2An-O2). Anthracene and 9-methylanthracene also undergo photocatalytic oxygenation with Acr+-Mes to afford the corresponding epidioxyanthracenes under the photoirradiation. In the case of anthracene, the further photoirradiation results in formation of anthraquinone as the final six-electron oxidation product, via 10-hydroxyanthrone, accompanied by generation of H2O2. When anthracene is replaced by olefins (tetraphenylethylene and tetramethylethylene), the photocatalytic oxygenation of olefins affords the corresponding dioxetane, in which the O-O bond is cleaved to yield the corresponding ketones. The photocatalytic oxygenation of anthracenes and olefins is initiated by photoexcitation of Acr+-Mes, which results in formation of the electron-transfer state: Acr?- Mes?+, followed by electron transfer from anthracenes and olefins to the Mes?+ moiety together with electron transfer from the Acr? moiety to O2. The resulting anthracene and olefin radical cations undergo the radical coupling reactions with O 2?- to produce the epidioxyanthracene (An-O 2) and dioxetane, respectively.
Kotani, Hiroaki,Ohkubo, Kei,Fukuzumi, Shunichi
p. 15999 - 16006
(2007/10/03)

Flow-vacuum pyrolysis of 2,5-diphenyl-4-methyloxazole
The flow-vacuum pyrolysis of 2,5-diphenyl-4-methyloxazole (4) at 1000°C and 0.5 Torr afforded a complex reaction mixture containing: benzonitrile, diphenylmethane, 9,10-dimethylphenantrene, 9,10-dimethylantracene, fluorene, o-benzylbenzonitrile (major product, 20-22%), phenanthrene, anthracene, o,o′-dicyanodiphenyl, 9,10-anthraquinone, 2-methyl-4,5-diphenyloxazole and 1,1,2,2-tetraphenylethane. A radical- and carbene mechanism is suggested in order to rationalize the formation of the reaction products.
Banciu, Mircea D.,Istrati, Daniela,Schiketanz, Iosif,Mihǎiescu, Dan,Drǎghici, Constantin,Malacea, Raluca
p. 493 - 499
(2007/10/03)

Non-steady-state kinetic studies of the real kinetic isotope effects and Arrhenius activation parameters for the proton transfer reactions of 9,10-dimethylanthracene radical cation with pyridine bases
The kinetics of the reactions between 9,10-dimethylanthracene radical cation and 2,6-diethylpyridine (DEP) in dichloromethane-Bu4NPF6 (0.2 M) as well as that with 2,6-dimethylpyridine (LUT) in acetonitrile-Bu4NPF6 (0.1 M) were studied at temperatures ranging from 252 to 312 K. In the time period before steady-state was reached for both reaction systems at all temperatures, the apparent deuterium kinetic isotope effects (KIEapp) were observed to increase with extent of reaction. The KIEapp-extent of reaction profiles provide strong evidence for a two-step mechanism [eqns. (i),(ii)] consisting of reversible complex formation prior to rate determining proton transfer. (i) ArCH3+. + B ? ArCH3+./B Keq = kf/kb (ii) ArCH3+./B → ArCH2. + BH+ kp (iii) ArCH2. + ArCH3+. + B → Products fast. Resolution of the kinetics into the relevant microscopic rate constants resulted in real deuterium kinetic isotope effects (KIEreal) which are much larger than KIEapp and were observed to increase markedly with decreasing temperature. Values of KIEreal ranged from 62 to 247. It is concluded that a significant degree of quantum mechanical tunneling is involved for both reaction systems. Activation parameters for apparent and microscopic rate constants are discussed with reference to the proton tunneling effect.
Zhao, Yixing,Lu, Yun,Parker, Vernon D.
p. 1481 - 1488
(2007/10/03)

Production of nitroxyl (HNO) at biologically relevant temperatures from the retro-Diels-Alder reaction of N-hydroxyurea-derived acyl nitroso-9,10- dimethylanthracene cycloadducts
Retro Diels-Alder reaction of N-hydroxyurea-derived acyl nitroso compound-9,10-dimethylanthracene cycloadducts produce acyl nitroso compounds that react with nucleophiles to form nitrous oxide, which indicates the intermediacy of nitroxyl. These results identify these molecules as a new group of nitroxyl delivery agents. (C) 2000 Elsevier Science Ltd.
Xu, Yueping,Alavanja, Maria-Michelle,Johnson, Veta L.,Yasaki, Genichiro,King, S. Bruce
p. 4265 - 4269
(2007/10/03)

Evolution of products in the combustion of scrap tires in a horizontal, laboratory scale reactor
A horizontal laboratory reactor was used to study the evolution of byproducts from the combustion of scrap tires at five nominal temperatures (ranging from 650 to 1050 °C) and different oxygen:sample ratios A model was used to calculate the bulk air ratio (λ), and the oxygen consumption was discussed considering this ratio λ. More than 100 volatile and semivolatile compounds were identified and quantified by gas chromatography mass spectrometry, plotting their yields vs the bulk air ratio and temperature. Five different behaviors considering the bulk air ratio and the temperature were identified.
Fullana,Font,Conesa,Blasco
p. 2092 - 2099
(2007/10/03)

Characterization of polycyclic aromatic hydrocarbon particulate and gaseous emissions from polystyrene combustion
The partitioning of polycyclic aromatic hydrocarbons (PAHs) between the particulate and gaseous phases resulting from the combustion of polystyrene was studied. A vertical tubular flow furnace was used to incinerate polystyrene spheres (100-300 μm) at different combustion temperatures (800- 1200 °C) to determine the effect of temperature and polystyrene feed size on the particulate and gaseous emissions and their chemical composition. The furnace reactor exhaust was sampled using real-time instruments (differential mobility particle sizer and/or optical particle counter) to determine the particle size distribution. For chemical composition analyses, the particles were either collected on Teflon filters or split into eight size fractions using a cascade impactor with filter media substrates, while the gaseous products were collected on XAD-2 adsorbent. Gas chromatography/mass spectroscopy (GC/MS) was used to identify and quantify the specific PAH species, their partitioning between the gas and particulate phases, and their distribution as a function of emission particle size. The total mass and number of PAH species in both the particulate and gas phases were found to decrease with increasing incineration temperature and decreasing polystyrene feed size, while the mean diameter of the particles increases with increasing incineration temperature and decreasing feed size. In addition, the PAH species in the particulate phase were found to be concentrated in the smaller aerosol sizes. The experimental results have been analyzed to elucidate the formation mechanisms of PAHs and particles during polystyrene combustion. The implications of these results are also discussed with respect to the control of PAH emissions from municipal waste-to-energy incineration systems. The partitioning of polycyclic aromatic hydrocarbons (PAHs) between particulate and gaseous phases resulting from the combustion of polystyrene was studied. A vertical tubular flow furnace was used to incinerate polystyrene spheres to determine the effect of temperature and polystyrene feed size on the particulate and gaseous emissions and their chemical composition. The furnace reactor exhaust was sampled using real-time instruments to determine the particle size distribution. The total mass and number of PAH species in both the particulate and gas phases were found to decrease with increasing incineration temperature and decreasing polystyrene feed size, while the mean diameter of the particles increases with increasing incineration temperature and decreasing feed size. In addition, the PAH species in the particulate phase were found to be concentrated in the smaller aerosol sizes.
Durlak, Susan K.,Biswas, Pratim,Shi, Jichun,Bernhard, Mary Jo
p. 2301 - 2307
(2007/10/03)

Application of non-steady-state kinetics to resolve the kinetics of proton-transfer reactions between methylarene radical cations and pyridine bases
Apparent deuterium kinetic isotope effects (KIE(app)) of four different methylarene radical cation-pyridine base reactions in dichloromethane (0.2 M tetrabutylammonium hexafluorophosphate) were observed to increase toward a constant value with increasing extent of reaction. The reactions were studied by derivative cyclic voltammetry (DCV), and rate constants were assigned by comparing the experimental with the theoretical DCV data. The kinetic results rule out a simple second-order proton-transfer reaction and implicate a mechanism in which a complex is first formed that then undergoes proton transfer, followed by separation of the products. That KIE(app) are extent of reaction-dependent is observed before steady-state is reached. The concurrent analysis of kinetic data for the reactions of both ArCH3(·+) and ArCD3(·+) with bases under non-steady-state conditions facilitates the resolution of the apparent rate constant [k(app) = k(f)k(p)/(k(b) + k(p))] into the microscopic rate constants (k(f), k(b), and k(p)) for the individual steps. The KIE(app) observed during proton-transfer reactions need not be the real kinetic isotope effects (KIE(real)). Having access to the microscopic rate constants for the steps in which the proton is transferred allows KIE(real) to be evaluated and compared with the corresponding KIE(app). The present study shows that the KIE(real) are much greater than the KIE(app) derived in the usual way from the rate of the overall reaction.
Parker, Vernon D.,Zhao, Yixing,Lu, Yun,Zheng, Gang
p. 12720 - 12727
(2007/10/03)

Friedel-Crafts Reaction with Arylcarbinols : One-Pot Synthesis of 10-Methylbenzo[a]fluoranthene
Friedel-Crafts reaction with some monoaryl and diaryl carbinols have been studied. The products suggest a rational mode of formation of trityl alcohol and anthracene derivatives modifying the earlier reported conjecture of their formation from carbon monoxide, generated from benzhydrol and solvent benzene. It now appears that during Friedel-Crafts reaction the benzyl carbocation generated from benzhydrol may be arylated to triphenylmethane derivative. The latter under the experimental condition forms trityl cation which abstracts the hydroxyl group from the benzhydrol to form benzyl carbocation and trityl alcohol. Benzyl carbocations act both as a nucleophile and an eletrophile and dimerize to form anthracene derivatives. Incidentally, a one-pot synthesis of 10-methylbenzo[a]fluoranthene (26), characterized by NOE, decoupling and mass spectral studies, has been achieved in good yield by the Friedel-Crafts reaction of 9-fluourenol, thus providing a simple method of its synthesis.
Talapatra, Bani,Chakraborty, Syamal,Biswas, Kallolmay,Mondal, Sudipta,Talapatra, Sunil Kumar
p. 788 - 794
(2007/10/03)

Acid catalysis vs. electron-transfer catalysis via organic cations or cation-radicals as the reactive intermediate. Are these distinctive mechanisms?
Proton transfer to aromatic and olefinic donors (D) leads to the facile interchange of transient carbocations (DH+) and cation-radical (D+.). The same types of cation and cation-radical are reactive intermediates in the acid catalysis and the electron-transfer catalysis of such organic transformations as benzylic coupling, epoxide/pinacol rearrangements and cis-trans isomerization of stilbenes when they are both carried out under otherwise identical reaction conditions. However, the rapid exchange of diamagnetic cations and paramagnetic cation-radicals blurs the traditional view of separate electrophilic and homolytic processes, and rigorous experimental evidence is required to establish whether acid catalysis and electron-transfer catalysis actually represent distinct mechanistic categories. Acta Chemica Scandinavica 1998.
Rathore, Rajendra,Kochi, Jay K.
p. 114 - 130
(2007/10/03)

INVESTIGATION OF THE COMPOSITION OF PETROLEUM ANTHRACENE HYDROCARBONS
The optimum conditions of adduct formation with maleic anhydride for the isolation of ca. 100percent anthracene hydrocarbons from a mixture with phenanthrenes and other compounds are set out.Gas-liquid chromatography has been used to study the individual composition of anthracene and C1-C3 anthracenes isolated by the method proposed from concentrates of triaromatic hydrocarbons of crude oils from the Okha, Katangli (Sakhalin) and Dorokhovsk (Urals-Volga) fields.With the aid of the individual compounds synthesized, for the first time 2-ethylanthracene and 1,3- and 2,3-dimethylanthracene have been identified in crude oils, and the retention indices have also been calculated for certain C2- and C3-substituted anthracene hydrocarbons for chromatographic phase SE-54.
Ivanov, V. I.,Golovko, A. K.
p. 504 - 512
(2007/10/02)

The rearrangements of α-imino-thioaldehydes into dihydro-1,3-thiazoles
α-Imino-thioaldehydes were generated by retro-Diels-Alder reaction under nash vacuum thermolysis conditions. They were found to be unstable and cyclized to 2,3-dihydro-1.3-thiazoles. This cyclization was investigated by ab initio calculations.
Arnaud,Pelloux-Leon,Ripoll,Vallee
p. 8389 - 8392
(2007/10/02)

Homogeneous catalysis of the hydrogenation of 9,10-dimethylanthracene to 1,2-dihydro-9,10-dimethylanthracene by
The cationic ruthenium arene complex, 6-9,10-dimethylanthracene)>+ (1), serves as a catalyst for the hydrogenation of 9,10-dimethylanthracene (2), initially to 1,2-dihydro-9,10-dimethylanthracene (3), followed by hydrogenation of the latter to 1,2,3,4-tetrahydro-9,10-dimethylanthracene (4).The first step, i.e., 2 --> 3, obeys the rate-law - d/dt = kcat, were kcat = (1.5 +/- 0.1) * 10-3 Μ-1 s-1 at 25 degC in CDCl3.
Lin, Zerong,Halpern, Jack
p. C24 - C27
(2007/10/02)

Magnesium Adducts of Substituted Anthracenes - Preparation and Properties
2-Methyl-, 1,4-dimethyl-, 9-methyl-, 9-ethyl-, 9,10-dimethyl-, and 9-phenylanthracene (1a-f) react with magnesium in THF at room temperature to afford the corresponding substituted magnesium anthracenes 2a-f. 9,10-Diphenylanthracene (1g), however, reacts with magnesium under the same conditions to produce the deep-blue magnesium bis(9,10-diphenylanthracenide) * 6 THF (4g).Upon heating to 60 deg C in THF, 4g reversibly dissociates to give magnesium 9,10-diphenylanthracene * 3 THF (2g) and 1g, while prolonged heating at 60 deg C causes decomposition of 2g to active magnesium (Mg*) and 1g.In THF 2a-c, e, and f exhibit temperature-dependent equilibria with 1a-c, e, and f and magnesium.Compared with magnesium anthracene * 3 THF (2), these equilibria are strongly shifted toward substituted anthracenes and magnesium, and only at 0 deg C high conversions are achieved.The magnesium exchange between 2 and the substituted anthracenes 1a, b, and f in THF has been experimentally verified. 2a, e, and f react with organic halides in the same way as 2, however, in the case of allyl, propargyl, and benzyl chloride the yields of Grignard compounds are lower than for 2; with bromobenzene, the tendency for the radical transfer reaction is stronger than for 2.Magnesium 9,10-dimethylanthracene (2e) reacts with ethyl acetate to give the bicyclic tertiary alcohol 9 by an intramolecular C-C coupling reaction.
Bogdanovic, Borislav,Janke, Nikolaus,Kinzelmann, Hans-Georg,Seevogel, Klaus,Treber, Joachim
p. 1529 - 1535
(2007/10/02)

KINETIC AND THERMOCHEMICAL INVESTIGATION OF THE FORWARD AND REVERSE DIELS-ALDER REACTIONS OF TETRACYANOETHYLENE WITH ANTHRACENE AND 9,10-DIMETHYLANTHRACENE IN CERTAIN SOLVENTS
The Diels-Alder reaction of tetracyanoethylene with anthracene and 9,10-dimethylanthracene was studied in the forward and reverse directions in a series of solvents.The rate constants, enthalpies and entropies of activation, enthalpies of solution of the reagents and adducts, and enthalpies of the reaction were determined.The changes in the enthalpy of solvation of the reagents, the products, and the transition state for the forward and reverse processes were calculated from the obtained data.The equality of the enthalpies of the reaction obtained from the thermochemical (ΔHr) and kinetic (ΔH1-ΔH-1) measurements suggests that the energies of intermolecular stabilization in the transition state for the forward and reverse Diels-Alder reactions are equal.The indentical changes in the enthalpy of solvation of the transition state for the forward and reverse reactions are consistent with its equilibrium solvation.
Kiselev, V. D.,Malkov, V. B.,Konovalov, A. I.
p. 191 - 200
(2007/10/02)

An E.S.R. Investigation of Radical Cations Formed in Friedel-Crafts Reactions
The present study deals with the detection and identification of radical cations produced in a Friedel-Crafts alkylating system, with benzene, toluene, or ethylbenzene, and an alkyl chloride.Our results indicate that the observed e.s.r. spectra are due to polycyclic aromatic radical cations formed from the parent hydrocarbons.It is suggested that benzyl halides produced in the Friedel-Crafts alkylating reaction undergo Scholl self-condensation to give polycyclic aromatic hydrocarbons, which are converted into the corresponding polycyclic aromatic radical cations in the presence of aluminium chloride.
Wang, Hanqing,Kispert, Lowell. D.,Sang, Hong
p. 1463 - 1470
(2007/10/02)

Syntheses of 9,10-Disubstituted Anthracenes Derived from 9,10-Dilithioanthracene
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Duerr, Brook F.,Chung, Y.-S.,Czarnik, Anthony W.
p. 2120 - 2122
(2007/10/02)

Diene-Substituent Effects on the Rate of the Retro-Diels-Alder Reaction. Cycloreversion Reactivity Varying over a Range of Five Powers of Ten
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Chung, Y.-S.,Duerr, Brook F.,Nanjappan, P.,Czarnik, Anthony W.
p. 1334 - 1336
(2007/10/02)

Intramolecular 'Ene' Reactions of Thioaldehydes
Allylic and homoallylic esters of thioxoacetic acid (1b), when generated by thermal cleavage of various Diels-Alder adducts in solution (111 deg C) or by flash vacuum pyrolysis (600 deg C), undergo intramolecular 'ene' reactions with C-C bond formation.
Choi, Samuel S-M.,Kirby, Gordon W.
p. 177 - 179
(2007/10/02)

REARRANGEMENT OF NITROCARBENES TO ACYL NITROSO COMPOUNDS
Acyl nitroso compounds may be trapped as eneophiles and Diels-Alder adducts under thermal and transition metal catalyst conditions using nitrodiazomethane, ethyl nitrodiazoacetate and trifluoromethylnitrodiazomethane.
O'Bannon, P. E.,Dailey, William P.
p. 5719 - 5722
(2007/10/02)

C-Nitrosoformamides, a New Class of Transient Dienophiles Formed by Oxidation of N-Hydroxyureas
Oxidation of hydroxyurea with sodium or tetraethylammonium periodate in the presence of cyclopentadiene gave a cycloadduct (3a) formed, apparently, by capture of the transient dienophile, C-nitrosoformamide.N-Methyl-, N-phenyl-, N,N-dimethyl-, and N,N-diphenyl-C-nitrosoformamide were likewise trapped as their cycloadducts with cyclopentadiene.Cycloadducts of 2,3-dimethylbuta-1,3-diene, thebaine, ergosteryl acetate, and 9,10-dimethylanthracene (DMA) were prepared similarly.The cyclopentadiene adducts (3) dissociated at 80 deg C in the presence of 2,3-dimethylbuta-1,3-diene to give the corresponding adducts (4) of the nitrosoformamides and dimethylbutadiene.Unexpectedly, the 1,4-adducts (4) were accompanied by substantial amounts of hydroxamic acids (5) arising from 'ene' reactions of the nitrosoformamides and dimethylbutadiene.The cyclopentadiene adducts of N,N-dimethyl- and N,N-diphenyl-C-nitrosoformamide, when heated alone, decomposed to give the corresponding carbamic anhydrides.The cycloadduct (15) of DMA and C-nitrosoformamide dissociated at 40 deg C in the presence of thebaine (11) to give the thebaine adduct (12; R=H) and DMA.
Christie, Clifford C.,Kirby, Gordon W.,McGuigan, Henry,Mackinnon, John W. M.
p. 2469 - 2474
(2007/10/02)

Dynamics of Transient Ion Pairs and Radical Pairs. Solvent and Salt Effects by Time-Resolved Spectroscopy
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Masnovi, J. M.,Levine, A.,Kochi, J. K.
p. 4356 - 4358
(2007/10/02)

REACTIONS OF CHLORINE DIOXIDE IN DICHLOROMETHANE I. FORMATION OF RADICAL CATIONS IN ACID MEDIA
Chlorine dioxide oxidises electron rich organic compounds to the corresponding radical cations in dichloromethane/TFA medium.In a different experimental set up using alkaline biphasic solvent system, its utility as hydrogen abstractor has been capitalized in the preparation of diazodiphenyl methane in good yield.
Handoo, Kishan L.,Handoo, S. K.,Gadru, Kanchan,Kaul, Anju
p. 1765 - 1768
(2007/10/02)

RADICAL CATIONS IN DISPROPORTIONATION REACTIONS OF ALKYLBENZENES
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Bazhenova, A. L.,Latysheva, L. E.,Chenets, V. V.,Laperdina, T. G.
p. 1869 - 1873
(2007/10/02)

Synthesis of 9-Methylene-9,10-dihydroanthracene by Lithium Aluminium Hydride Reduction of (9-Anthrylmethyl)trimethylammonium Chloride
Treatment of (9-anthrylmethyl)trimethylammonium chloride (2a) with 1 mol equiv. of lithium aluminium hydride (LAH) in refluxing tetrahydrofuran gave predominantly 9-methylene-9,10-dihydroanthracene (3a).However, reaction with 3 mol equiv. of LAH gave a mixture of 9-methyl-9,10-dihydroantracene (5a) and 9-(9-anthrylmethyl)-9-methyl-9,10-dihydroanthracene (6a), these products being formed by processes involving nucleophilic attack of excess of LAH on compound (3a).
Takagi, Masato,Hirabe, Tomoatsu,Nojima, Masatomo,Kusabayashi, Shigekazu
p. 1311 - 1314
(2007/10/02)

ADDITION REACTIONS OF SOME SIMPLE THIOALDEHYDES.
When generated at 100 deg C, aliphatic and aromatic thioaldehydes without electronic bias are shown to undergo addition reactions to both aliphatic and aromatic 1,3-dienes.The reaction is shown to have application in an intramolecular example.
Baldwin, Jack E.,Lopez, Gerald R. C.
p. 1487 - 1498
(2007/10/02)

GENERATION AND THE AMBIDENT CHARACTER OF 9-ANTHRYLMETHYL CARBANIONS
9-Methoxymethylanthracene, 9-trimethylsilylmethylanthracene and 9-thiomethoxymethylanthracene are converted by butyllithium reagents to α-methoxy-9-anthrylmethyl, α-trimethylsilyl-9-anthrylmethyl and 9-anthrylmethyl carbanions, respectively, which react at their C-10 and C-11 positions with appropriate electrophyles.
Engler, T. A.,Shechter, H.
p. 4645 - 4648
(2007/10/02)

Carbon-13 NMR Spectroscopic Study of Substituted Anthracene Dications
A series of substituted anthracenes (2-10 and 20-21) were oxidized by SbF5/SO2ClF at 0 to -30 deg C to their dications (11-19 and 22-23), which were observed by carbon-13 NMR spectroscopy.In the studied anthracene dications substantial positive charge was found to be localized at C9 and C10 positions.Methyl substitution in these dications was found to deshield the α-carbons as compared to their shielding effect in the corresponding monocations.The proportionality factor of (13)C chemical shift to electron density was found to be 174.1-217.0 ppm/e-, clearly proving the dicationic nature of the ions.
Olah, George A.,Singh, Brij P.
p. 4830 - 4835
(2007/10/02)

Formation of Isocyanates by Deoxygenation of C-Nitrosocarbonyl Compounds
The cycloadduct (1a) of 9,10-dimethylanthracene (2) (hereinafter referred to as DMA) and nitrosocarbonylbenzene decomposed in benzene at 80 deg C in the presence of triphenylphosphine to give DMA, triphenylphosphine oxide, and phenyl isocyanate in high yield.The corresponding adducts of 4-chloro-(1b), 4-methoxy-(1c), and 4-nitro-nitrosocarbonylbenzene (1d) behaved likewise.The cycloadduct of DMA and 4-methoxybenzylnitrosocarbonylmethane (1e) and of DMA and 1-(4-methoxyphenyl)-2-nitrosocarbonylethane (1f) gave lower (20-30 percent) yields of isocyanates.The rates of decomposition of the adduct (1a) in the presence of either the conjugated diene thebaine (3) or various phosphorus(III) derivatives were the same within experimental error.A similar observation was made for compound (1d).The formation of isocyanates is believed to involve slow dissociation of the cycloadducts followed by rapid deoxygenation of the transient nitrosocarbonyl compounds by triphenylphosphine.Stable complexes (8) of triphenylphosphine oxide with N-(4-nitrophenyl)-N'-propylurea and N-(4-nitrophenyl)-N'-phenylurea are described.
Corrie, John E.T.,Kirby, Gordon W.,Sharma, Ram P.
p. 1571 - 1574
(2007/10/02)

Titanium-Induced Reductive Elimination. Syntheses of 1,3-Dienes
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Walborsky, H. M.,Wuest, H. H.
p. 5807 - 5808
(2007/10/02)

Formation and Thermal Cleavage Reactions of the Cycloadduct of 9,10-Dimethylanthracene and Nitrosyl Cyanide
Nitrosyl cyanide and 9,10-dimethylanthracene (DMA) (2) reacted at -25 deg C to form the crystallyne cycloadduct, 9,10-dihydro-9,10-(N-cyanoepoxyimino)-9,10-dimethylanthracene (1).The adduct (1) decomposed in the presence of the conjugated diene thebaine (3), to form DMA(2) and the adduct (4) of nitrosyl cyanide and thebaine.First-order kinetics, k = 6.9E-5 s-1, were observed for the release of DMA in benzene at 40 deg C, consistent with slow dissociation of the adduct (1) followed by rapid capture of nitrosyl cyanide by thebain.A similar first-order rate, k = 6.8E-5 s-1, was observed for the reaction of the adduct (1) and triphenylphosphine (2 mol equiv.) under the same conditions, the products being DMA, triphenylphosphine oxide, and triphenylphosphine N-cyanoimide (5).The reactions of nitrosyl cyanide, generated thermally from the adduct (1), were studied with a range of dienes.The conjugated dienes, N-cyanomethyl-N-northebaine (3; NCH2CN replacing NMe), trans,trans-1,4-diphenylbuta-1,3-diene (6; R=H), and ergosteryl acetate (11) all gave the expected cycloadducts (3,6-dihydro-2H-1,2-oxazines).Norbornane gave the tetracyclic adduct (10) arising from 1,4-conjugate addition of nitrosyl cyanide.The reactions of the adduct (1) with tetraphenylcyclopentadienone (14), 1,3-diphenylisobenzofuran (18), 2-methyl-1,3-diphenylisoindole (23), diazofluorene (24), and diphenyldiazomethane all took a more complex course leading in each case to the formation of an N-cyano-ketimine (alkylidene-cyanamide)
Horsewood, Peter,Kirby, Gordon W.,Sharma, Ram Prakash,Sweeny, James
p. 1802 - 1806
(2007/10/02)

A VERSATILE METHOD FOR CARBON-NITROGEN BOND FORMATION VIA ENE REACTIONS OF ACYLNITROSO COMPOUNDS
The use of acylnitroso compounds of the general formula RCONO as enophiles in the formation of carbon-nitrogen bonds is discribed.Both inter- and intramolecular ene reactions have been studied.For the intermolecular examples, nitrosocarbonylmethane, thermally liberated from its Diels-Alder adduct with 9,10-dimethylanthracene, is reacted with variuos olefins giving the corresponding N-alkylhydroxamic acids in moderate to high yields, providing an efficient method for allylic amidation.The regiochemistry of the intermolecular reaction is observed to be the result of kinetic control, and the direction of addition is consistent with attack by the olefin on electron-deficient nitrogen.Several examples of intramolecular ene cyclization are demonstrated, providing efficient entry into both spiro and fused bicyclic nitrogen containing systems which can be viewed as derived from annulation of 5- and 6-membered nitrogen containing ring onto 5- and 6-membered carbocycles, respectively.Various examples of this hetero-annulation scheme are described.Experimental details are also privided describing typical reaction procedures.
Keck, Gary E.,Webb, Robert R.,Yates, John B.
p. 4007 - 4016
(2007/10/02)

Formation and Dienophilic Reactions of Transient C-Nitrosocarbonyl Compounds
Oxidation of benzohydroxamic acid with tetraethylammonium periodate in the presence of the conjugated diene thebaine (1) gave the cycloadduct 6β,14β-(N-benzoylepoxyimino)-6,14-dihydrothebaine (2; R = Ph), in high yield.The corresponding N-acetyl derivative (2; R = Me) was prepared similarly using acetoxyhydroxamic acid.Likewise, 2-benzoyl- and 2-acetyl-3,6-dihydro-2H-1,2-oxazine (5; R = Ph) and (5; R = Me) were obtained from buta-1,3-diene, and the N-benzoyl and N-acetyl derivatives of 9,10-epoxyimino-9,10-dihydro-9,10-dimethylanthracene (6; R = PhCO) and (6; R = Ac) from 9,10-dimethylanthracene (DMA).These reactions are believed to involve the formation of nitrosocarbonylbenzene or nitrosocarbonylmethane, representatives of a new class of transient, reactive species.The cycloadduct (6; R = Ac) decomposed in benzene at 60 deg C in the presence of thebaine (1) to give the thebaine adduct (2; R = Me) and DMA.First-order kinetics were observed for the release of DMA, consistent with slow dissociation of the adduct (6; R = Ac) followed by rapid capture of nitrosocarbonylmethane by thebaine.The related adduct (6; R = PhCO) behaved similarly.DMA adducts of the type (6) are valuable in studies on the reactions of nitrosocarbonyl compounds, especially with co-reactants sensitive to oxidation.Thus (6; R = Ac) and 1,3-diphenylisobenzofuran (7) reacted cleanly in benzene at 80 deg C to give the O-acetyloxime (10) of 1,2-dibenzoylbenzene, possibly via the N-acetylnitrone (9) derived from the initially formed cycloadduct (8).
Kirby, Gordon W.,Sweeny, James G.
p. 3250 - 3254
(2007/10/02)

Deoxygenation of Arene 1,4-Endoxides with Low-Valent Metals
Low-valent forms of iron, tungsten, and titanium, produced by treatment of the metal chlorides with butyllithium at -78 deg C, are useful deoxygenation catalysts for the conversion of 1,4-endoxides to the corresponding arenes in a single step.In some instances, particulary with highly substituted endoxides, other reactions may interefere.For example, with methyl substituents at C2 and C3 and with reduced iron, reduction of the C2-C3 double bond and a 1,3 hydrogen shift occur.Also, hindered aromatic methoxyls may be replaced by hydrogen.Use of this deoxygenationmethod to prepare 1,4,5,8,9,10-hexamethylanthracene, a compound with multiple peri interactions, is described.
Hart, Harold,Nwokogu, Godson
p. 1251 - 1255
(2007/10/02)

Reactions of Copper(II) Halides with Aromatic Compounds. Part XII. Reactions of 9-Methyl-10-phenylanthracene, 1,4,9-Trimethylanthracene, 9,10-Dimethylanthracene and 1,5-Dichloro-9-methylanthracene in Methanol.
The title compounds react with copper(II) bromide in methanol to give the corresponding 9-methoxymethyl compounds. 1,4,9-Trimethylanthracene and 1,5-dichloro-9-methylanthracene also gave 1,2-di-(1,4-dimethyl-9-anthryl)ethane (6) and 1,5-dichloro-9,10-dimethoxy-9,10-dihydroanthracene (9) respectively.The formation of all these products can be interpreted in terms of initial electron transfer oxidation of the substituted anthracene to its radical cation, which either subsequently loses a proton to give the substituted 9-anthrylmethyl radical or undergoes solvent capture.
Mancilla, Jerson M.,Nonhebel, Derek C.,Scullion, Ian
p. 1601 - 1619
(2007/10/02)

MUTUAL TRANSFORMATIONS OF THE DICATIONS OF ALKYL AROMATIC COMPOUNDS AND THEIR CONJUGATE CATIONS OF BENZYL TYPE
For ions of the anthracene and naphthalene series it was only possible to observe transitions betveen the dications of alkyl aromatic compounds (2+) and cations of the benzyl type ArCH(+)R (R = CH3, H), which are conjugated acids and bases, for the case of the thermodynamically favorable transformation of the dication into the conjugate monocation.Even if it is favorable in thermodynamic respects, the reverse transformation involves overcoming a high activation barrier, which is evidently due to electrostatic repulsion of the proton and of the positively charged center being protonated.
Bodoev, N.V.,Krysin, A.P.,Koptyug, V.A.
p. 880 - 885
(2007/10/02)