447-53-0Relevant articles and documents
The effect of pressure on hydrogen transfer reactions with quinones
Wurche, Frank,Sicking, Wilhelm,Sustmann, Reiner,Klaerner, Frank-Gerrit,Ruechard, Christoph
, p. 2707 - 2721 (2004)
The effect of pressure on the oxidation of hydroarenes 3-9 with 2,3-dichloro-5,6-dicyano-1,4-quinone (DDQ; 1a) or o-chloranil (10), leading to the corresponding arenes, has been investigated. The activation volumes were determined from the pressure dependence of the rate constants of these reactions monitored by on-line UV/Vis spectroscopic measurements in an optical high-pressure cell (up to 3500 bar). The finding that they are highly negative and only moderately dependent on the solvent polarity (ΔV ?=-13 to -25 in MTBE and -15 to -29 cm3mol -1 in MeCN/AcOEt, 1:1) rules out the formation of ionic species in the rate-determining step and is good evidence for a hydrogen atom transfer mechanism leading to a pair of radicals in the rate-determining step, as was also suggested by kinetic measurements, studies of kinetic isotope effects, and spin-trapping experiments. The strong pressure dependence of the kinetic deuterium isotope effect for the reaction of 9,10-dihydroanthracene 5/5-9,9,10,10-D4 with DDQ (1a) can be attributed to a tunneling component in the hydrogen transfer. In the case of formal 1,3-dienes and enes possessing two vicinal C-H bonds, which have to be cleaved during the dehydrogenation, a pericyclic hydrogen transfer has to considered as one mechanistic alternative. The comparison of the kinetic deuterium isotope effects determined for the oxidation of tetralin 9/9-1,1,4,4-D4/9-2,2,3,3-D4/9-D 12 either with DDQ (1a) or with thymoquinone 1c indicates that the reaction with DDQ (1a) proceeds in a stepwise manner through hydrogen atom transfer, analogously to the oxidations of 1,4-dihydroarenes, whereas the reaction with thymoquinone 1c is concerted, following the course of a pericyclic hydrogen transfer. The difference in the mechanistic courses of these two reactions may be explained by the effect of the CN and Cl substituents in 1a, which stabilize a radical intermediate better than the alkyl groups in 1c. The mechanistic conclusions are substantiated by DFT calculations.
Transfer of Hydrogen by Hydroaromatics. 2. The Temperature Dependence of the Rate Constants and Catalytic Site Populations in the Tetralin/Iron Catalyst Systems
Gangwer, T.E.
, p. 575 - 579 (1981)
The heterogeneous mechanism of dehydrogenation for the tetralin/iron catalyst system previously reported is further documented.The temperature dependences of the rate constants are reported.The effective activation energies on these heterogeneous surface were found to be in the -20 to +30 kcal/mol range.The catalytic site populations and temperature dependences were used to determine the binding energy, Rb, of the organic reactants at the catalytic sites.The Eb values were found to be in the 20-40 kcal/mol range.
Oxidation of cyanobenzocycloheptatrienes: Synthesis, photooxygenation reaction and carbonic anhydrase isoenzymes inhibition properties of some new benzotropone derivatives
Gueney, Murat,Coskun, Ahmet,Topal, Fevzi,Dastan, Arif,Guelcin, Ilhami,Supuran, Claudiu T.
, p. 3537 - 3543 (2014)
The oxidation of some cyanocycloheptatrienes with CrO3 and pyridine was investigated and a few new nitrile functionalised benzotropone derivatives were obtained. Photooxygenation reaction of these products was also studied. The structures of the formed products were determined on the basis of NMR spectroscopy and the formation mechanism of unusual products was discussed. Human carbonic anhydrase isoenzymes I, and II (hCA I and hCA II) inhibition properties of nitrile functionalized new benzotropone derivatives were also studied. Both CA isozymes were inhibited in the low micromolar range by these nitrile functionalized benzotropone analogues. The newly synthesized benzotropone derivatives showed inhibition constants in the sub-micromolar range (2.51-4.06 μM). The best hCA I inhibition was observed in 5H-benzocycloheptene-7-carbonitrile (Ki: 2.88 ± 0.86 μM). On the other hand, 5-oxo-5H-benzocycloheptatriene-7-carbonitrile showed the powerful inhibitory effect against hCA II (Ki: 2.51 ± 0.34 μM).
Cycloallenes. Part 15:1 3δ2-1H-naphthalene (2,3-didehydro-1,2- dihydronaphthalene) from 3-bromo-1,2-dihydronaphthalene
Groetsch, Stefan,Spuziak, Joanna,Christl, Manfred
, p. 4163 - 4171 (2000)
As a test as to whether the title intermediate 13 can be liberated from 3-bromo-1,2-dihydronaphthalene (19), the latter was treated with potassium tert-butoxide (KOtBu). Being the major products, naphthalene (20) and 3-tert- butoxy-1,2-dihydronaphthalene (21) provide unambiguous evidence for the intermediacy of 13. When the reaction was carried out in the presence of furan, 2,5-dimethylfuran and spiro[2,4]hepta-4,6-diene, expected (31, 32, 33, 34) and unexpected compounds (30, 35-37) were formed, which either directly resulted from the cycloaddition of 13 or were consecutive products of cycloadducts. Performed in the presence of benzophenone, the generation of 13 gave, inter alia, naphth-2-yldiphenylmethanol (27). This product testifies the intermediacy of the naphth-2-yl anion (24), which emerged from the deprotonation of 13 and was trapped by benzophenone. (C) 2000 Elsevier Science Ltd.
Stoichiometry of protonation of aromatic hydrocarbon radical anions by weak proton donors. A marked discrepancy between the number of protons used and those incorporated into the aromatic structure
Screttas, Constantinos G.,Ioannou, Georgios I.,Micha-Screttas, Maria
, p. 217 - 225 (1996)
The stoichiometries of the reaction between alkali metal radical anions of biphenyl, naphthalene, phenanthrene and anthracene, and methanol and/or other proton donors have been determined by the magnetic titration technique. In the case of naphthalene radical anion and, for example, methanol as the proton source, the stoichiometry was found to be cation-dependent: Li, 2: 1; Na, 1.75: 1; K, 1.33: 1. The reaction products using the experimentally determined stoichiometric conditions were ca. 95% naphthalene and 5% dihydronaphthalene(s). Thus, a marked discrepancy is observed between the protons used and those incorporated into the naphthalene molecule. Radical anions, at concentrations comparable with those of preparative reactions, react with carbon acids or amines according to the first-order kinetic law, although the initial concentrations of the two reactants were of the same order of magnitude or even equal. Lithium anthacene radical anion reacts with phenylacetylene and diethylamine at comparable rates, although the two "acids" differ in their acidities by ca. 10 orders of magnitude. A deuterium isotope effect of 2.49 ± 0.05 was observed in the reaction between lithium anthracene radical anion and diethylamine. A general reaction scheme is proposed that involves electron transfer to the proton donor and hydrogen-atom attack on the neutral hydrocarbon as the key reaction steps.
Hybrid Class Phenylthiazole and 1,2,3,4-Tetrahydronaphthalene Target Sertraline Transporter for Antidepressant Action Revealed by Molecular Docking Studies
Uppal, Archana,Kothiyal, Preeti,Singh, Anita
, p. 1429 - 1437 (2015)
Phenylthiazolyl-substituted 1,2,3,4-tetrahydronaphthalene derivatives were synthesized, and their chemical structures were elucidated by Fourier transform infrared, 1H-NMR, 13C-NMR spectral data and elemental analyses. Antidepressant-like activities of these compounds were screened using both Porsolt's behavioural despair on albino mice and tail suspension tests. Open field test was also performed for the examination of probable neurological deficits, which may interfere with the test results. The test compounds exhibited different levels of antidepressant activities. Additionally, the key ligand was further substantiated by docking experiment to explore plausible mode of binding in molecular dynamics overflow. The studies elucidates role of a hydrophilic H-bonding region and pi-cation binding as a major driving force for biological activity.
Intramolecular electrophilic aromatic substitution reactions with methyl vinyl ethers for the synthesis of dihydronaphthalenes
Harrowven, David C,Tyte, Melloney J
, p. 5971 - 5972 (2002)
A simple and inexpensive method to effect the conversion of 4-arylalk-1-en-1-yl methyl ethers to dihydronaphthalenes has been developed. Cyclisation is accomplished by warming a toluene solution of the substrate with 1,2-ethanediol and para-toluenesulfonic acid and proceeds via in situ formation of a 1,3-dioxolane. Reactions generally give good yields and have been successful with electron rich, unsubstituted and halogenated arenes. They display excellent regioselectivity; appearing to follow the course of lowest steric demand.
1-H-Cyclobuta[a]naphthalen-2-one
Neudeck, Horst,Brinker, Udo H.
, p. 1893 - 1895 (2005)
1-H-Cyclobuta[a]naphthalen-2-one (2) was synthesized in eight steps starting from α-tetralone. With 2 the last missing compound of the three possible cyclobutanaphthalenones has been prepared.
Transfer of Hydrogen by Hydroaromatics. 1. Mechanism of Dehydrogenation/Hydrogenation in Tetralin/Iron Catalyst Systems
Gangwer, T.
, p. 2436 - 2441 (1980)
At 400 deg C, the gas-phase dehydrogenation of teralin over iron catalysts is found to result in formation of naphthalene via the reaction of intermediate 1,2-dihydronaphthalene.The kinetic data for these systems were found to follow heterogeneous, first-order rate laws.A mechanism is presented which quatitatively describes the measured teralin and naphthalene kinetic behavior and successfully predicts the kinetic data observed for the 1,2-dihyronaphthalene intermediate.The rate-limiting reactions inthese systems are proposed as involving dehydrogenation/hydrogenation reactions on the surfaces of the catalysts.Based on data analysis, the rate constants for the surface reactions have values in the 1E-4-1E-5 s-1 range.The catalytic surface site populations were found to be in the range 1E13-1E14 molecules cm-2.
Broadening the scope of photostimulated SmI2 reductions
Amiel-Levy, Mazal,Hoz, Shmaryahu
, p. 805 - 809 (2010)
A study was conducted to demonstrate that the exploitation of the biomolecular process significantly broadened the scope of photostimulated SmI2 reduction. Two UV cells containing naphthalene, SmI2, and MeOH were set up under a preliminary test and one of them was exposed to a simple UV lamp, while the other was placed on the bench as a control under ordinary laboratory fluorescent lighting. It was observed that the reaction in the cell under the UV lamp progressed slowly, while significant reaction took place in the cell on the bench. Significant reaction was also observed when the same reaction was carried out with a mercury lamp and a filter that cut off wavelengths below 600 nm. Two methods were employed for the assessment of the photostimulated reactions. One of the methods was based on the fact that stopped flow irradiated the sample continuously in the diode array mode.
