4485-03-4

Upstream product

• 90-44-8 anthracen-9(10H)-one 
• 716-53-0 9-chloroanthracene 
• 1564-64-3 9-Bromoanthracene 
• 523-27-3 9,10-Dibromoanthracene 
• 22362-86-3 9-iodoanthracene 

Relevant academic research and scientific papers

The Solvent as H-Atom Donor in Organic Electrochemical Reactions. Reduction of Aromatic Halides

The first step following the initial formation of the anionic radical in the electrochemical reduction of aromatic halides in the cleavage of the C-X bond leading to the neutral Ar. radical.The latter species undergoes three concurrent reactions: H-atom abstraction from the solvent and electron transfer at the electrode and/or from the initial anion radical.The quantitative analysis of this threefold competition allows one to predict the effect of the intrinsic (rate constants) and operational (concentration, stirring rate, cell geometry) parameters.It is the basis on which the results of deuterium incorporation by deuterated water or solvent can be used as a tool to investigate the reaction mechanism and to determine the characteristic rate constants.This is illustrated by the study of the chloro, bromo, and iodo derivatives of three aromatic residues (9-anthryl, 1-naphthyl, and 4-cyanophenyl) in Me2SO and acetonitrile.It is shown that the proposed reduction mechanism is indeed followed in each case and the degree of competition between the three concurrent steps can be evaluated.Using the values obtained independently (by cyclic voltammetry or redox catalysis) for the cleavage rate of the anion radicals of the chloro compounds, the corresponding rates for the bromo and iodo derivatives are determined as well as the rates of H-atom transfer to the three aromatic radicals and the magnitude of the corresponding deuterium isotope effects.

Isotope shifts in polycyclic aromatic hydrocarbon anions

Isotope shifts are a well established tool for structural analysis by NMR. The substitution of a proton with a deuterium is the most widely studied of these effects. We have synthesized all three monodeuterated anthracenes and shown that their 13C spectra provide the same information that can be obtained from perdeuterated anthracene. The isotope shifts change when the PAH is reduced by an alkali metal. For a planar molecule such as anthracene, the isotope shifts change in approximate proportion to the change in charge density. However, when there is steric hindrance, such as in chrysene, reduction weakens the framework, allowing conformational change that substantially alters the isotopic shifts.

Oxidation of polycyclic aromatic hydrocarbons catalyzed by iron tetrasulfophthalocyanine FePcS: Inverse isotope effects and oxygen labeling studies

Iron(III) tetrasulfophthalocyanine (FePcS) was shown to catalyze the oxidation of polycyclic aromatic hydrocarbons by H2O2. Benzo[a]pyrene and anthracene were converted to the corresponding quinones while biphenyl-2,2′-dicarboxylic acid was the main product of phenanthrene oxidation. The mechanism of the anthracene oxidation by H2O2 in the presence of FePcS or by KHSO5 with iron(III) mesotetrakis(3,5-disulfonatomesityl)porphyrin (FeTMPS) (see Figure 1 for catalyst structures) has been investigated in details by using kinetic isotope effects (KIEs) and 18O labeling studies. KIEs measured on the substrate consumption in the competitive oxidation of [H10] anthracene and [D10]anthracene by FePcS/H2O2 and FeTMPS/KHSO5 were essentially the same, 0.75 ± 0.02 and 0.76 ± 0.06, respectively. These inverse KIEs on the first oxidation step can be explained by the sp2-to-sp3 hybridization change during the addition of an electrophilic oxoiron complex to the sp2 carbon center of anthracene to form a σ adduct (this inverse KIE being enhanced by stronger slacking interactions between the perdeuterated substrate with the macrocyclic catalyst). Although the first oxidation step seems to be the same, different distribution of the oxidation products of anthracene and very different 18O incorporation into anthrone and anthraquinone in catalytic oxidations performed in the presence of H218O suggested that different active species should be responsible for anthracene oxidation in both catalytic systems. All the results obtained are compatible with an involvement of TMPSFeV=O (or TMPS+FeIV=O), having two redox equivalents above the iron(III) state of the metalloporphyrin precursor, while PcSFeIV=O (one redox equivalent above FeIII state of FePcS) was proposed to be the active species in the metallophthalocyanine-based system.

Photochemical Transformations. 40. Syn and Anti Migration in Photo-Wagner-Meerwein Rearrangements

The photochemistry of the trans and cis isomers of 7,8-dichloro-2,3:5,6-dibenzobicycloocta-2,5-diene (1 and 3) has been explored.The singlet excited states of these compounds are photoactive.In acetonitrile, mixtures of exo- and endo-4,anti-8-dichloro-2,3:6,7-dibenzobicycloocta-2,6-diene (2-Cl), the syn-8-chloro epimers exo- and endo-4-Cl, N-(anti-8-chloro-2,3:6,7-dibenzobicycloocta-2,6-dien-exo-4-yl)acetamide (2-NHAc) and its syn-8-chloro epimer exo-4-NHAc were produced.In acetic acid, the dichloro compounds and a mixture of the anti- andsyn-8-chloro-2,3:6,7-dibenzobicycloocta-2,6-dien-exo-4-yl acetates (2-OAc and 4-OAc) were produced.In cyclohexane, irradiation of 2 gave the dichlorides epimeric at C-4 and C-8.All of the photoreactions proceeded with a preponderance of migration with retention at the migration terminus (syn migrations), in contrast to the ground-state reactions which proceed with clean inversion at the migration terminus (anti migration).Failure to see stereospecificity was shown not to be due to C-8 bridge migration.Quantum yields for the various reactions are reported.The results are discussed in terms of several reaction channels following excitation and electron transfer.Radical reductive monodechlorinations of 1 and 3 lead to stereoconvergent radical rearrangements.The syntheses of 2-NHAc and 4-NHAc by Ritter reactions from 2-OAc and 4-OAc respectively are described.

COMPETITION ENTRE SUBSTITUTION NULCEOPHILE ET REDUCTION CHEZ LES BROMO-9 ANTHRACENES DANS L'ACTION DES ANIONS PHENATE ET METHYLATE; APPLICATION A LA MONO-DEUTERIATION SPECIFIQUE EN MESO EN SERIE ANTHRACENIQUE

Treatment of meso-substituted 9-bromoanthracenes bearing no hydrogen in the α position with potassium phenoxide in DMF gives rise to a competition between nucleophilic substitution and reductive dehalogenation.Derivatives carrying electron attracting groups, 1c (Br), 1e (CN) and 1f (NO2), react essentially by substitution leading to phenolic ethers 2, whereas with non-activated bromides, 1a (H), 1b (C6H5) and 1d (OC6H5), the main reaction is a reduction to anthracenes 3 which should arise from an electron transfer.A reduction of 9-bromoanthracene into anthracene is also observed with sodium methoxide and it is shown, by labelling, that this one must result from a hydride transfer from methoxide.It may be applied to the specific meso-monodeuterization of various anthracenic derivatives.