Anthracenes reactions

A database is not usually a mere collection of values quoted from the literature. It commonly involves some critical assessment of those values and an effort to present a consistent set of data. It is important to clarify what we mean by consistency. Suppose that 40 years ago, somebody made a careful determination of the standard enthalpy of combustion of anthracene (reaction 2.20) and obtained Ac//°(Ci4Hio, cr) = X kJ mol-1. 

We know that C6-cyclization of 1-(naphthyl-2)-butene is possible without metal catalysts. The products are dihydrophenanthrene over quartz and 1,2,3,4-tetrahydrophenanthrene plus phenanthrene over alumina (50). The latter apparently catalyzes the redistribution of hydrogen in dihydrophenanthrene. Neither anthracene nor dihydro- or tetrahydroanthracene are formed over quartz or alumina from 1-(naphthyl-2)-butene. Plate and Erivanskaya concluded from this that the 2-alkylnaphthalene - anthracene reaction does not involve naphthylbutene intermediate (27). 

Perinaphthalyne (16) evidently prefers to react by hydrogen abstraction and insertion, giving naphthalene, biphenyl and phenylnaphthalene but relatively little anthracene (Reaction scheme 13) ... 

Diphenylcyclopropenes (106—108, Scheme 11) have been shown to quench the fluorescence of 9,10-dicyanoanthracene. When these compounds are irradiated in the presence of the anthracene, reaction products are obtained that are different from those obtained by either direct or triplet-sensitized irradiation. The route to products (Scheme 11) fits best with an electron-transfer process from the... 

Hofmann used a triptycene type backbone for preparing diphosphite 145, in overall 40% yield from three steps, starting from a conveniently substituted anthracene. Reaction of the substituted anthracene with dimethyl fumarate under microwave irradiation considerably reduced reaction time to prepare the triptycene derivative. After deprotection, the corresponding diol was then treated with chlorophosphite to give 145. The ligand was used in theoretical studies on rhodium(i)-catalysed hydroformylation of butadiene. The same authors also prepared iridium complex 146, from the already known diphosphite, which was used for the same purpose. 

Synthesis of octakisl[2- 4-(9-anthracenyl)phenyl ethenyl] octasilsesquioxane via cross-metathesis of octavinyisiisesquioxane with 9-(4-vinyiphenyi)anthracene Reaction Scheme 3 ... 

Anthracene is oxidised by chromium trioxide, Cr04, to anthraquinone. As the reaction is carried out in solution, a solvent is required which will dissolve both the anthracene and the chromium trioxide, and at the same time be... 

In the following preparation, this reaction is exemplified by the union of anthracene with maleic anhydride, to form 9,io-dihydroanthracene-9,io-e do-a -succinic anhydride note that as a result of this reaction both the outer rings of the anthracene system become truly aromatic in character. 

The Dieb-Alder reaction is a purely cia addition the relative positions of the substituents are retained in the adduct (compare anthracene and maleic anhydride above). ... 

Breslow studied the dimerisation of cyclopentadiene and the reaction between substituted maleimides and 9-(hydroxymethyl)anthracene in alcohol-water mixtures. He successfully correlated the rate constant with the solubility of the starting materials for each Diels-Alder reaction. From these relations he estimated the change in solvent accessible surface between initial state and activated complex " . Again, Breslow completely neglects hydrogen bonding interactions, but since he only studied alcohol-water mixtures, the enforced hydrophobic interactions will dominate the behaviour. Recently, also Diels-Alder reactions in dilute salt solutions in aqueous ethanol have been studied and minor rate increases have been observed Lubineau has demonstrated that addition of sugars can induce an extra acceleration of the aqueous Diels-Alder reaction . Also the effect of surfactants on Diels-Alder reactions has been studied. This topic will be extensively reviewed in Chapter 4. 

The cases of pentamethylbenzene and anthracene reacting with nitronium tetrafluoroborate in sulpholan were mentioned above. Each compound forms a stable intermediate very rapidly, and the intermediate then decomposes slowly. It seems that here we have cases where the first stage of the two-step process is very rapid (reaction may even be occurring upon encounter), but the second stages are slow either because of steric factors or because of the feeble basicity of the solvent. The course of the subsequent slow decomposition of the intermediate from pentamethylbenzene is not yet fully understood, but it gives only a poor yield of pentamethylnitrobenzene. The intermediate from anthracene decomposes at a measurable speed to 9-nitroanthracene and the observations are compatible with a two-step mechanism in which k i k E and i[N02" ] > / i. There is a kinetic isotope effect (table 6.1), its value for the reaction in acetonitrile being near to the... 

Butenediol is a weak dienophile in Diels-Alder reactions. Adducts have been described with anthracene (108) and with hexachlorocyclopentadiene... 

Ring formation readily occurs ia the alkylation of aromatics with di- and polyhaUdes, eg, the reaction of di- and ttihalomethanes with aromatics ia the presence of aluminum chloride. In the reaction of dichioromethane and ben2ene, besides diaryknethanes, anthracene derivatives are also formed (54). 

Examples include luminescence from anthracene crystals subjected to alternating electric current (159), luminescence from electron recombination with the carbazole free radical produced by photolysis of potassium carba2ole in a fro2en glass matrix (160), reactions of free radicals with solvated electrons (155), and reduction of mtheiiium(III)tris(bipyridyl) with the hydrated electron (161). Other examples include the oxidation of aromatic radical anions with such oxidants as chlorine or ben2oyl peroxide (162,163), and the reduction of 9,10-dichloro-9,10-diphenyl-9,10-dihydroanthracene with the 9,10-diphenylanthracene radical anion (162,164). Many other examples of electron-transfer chemiluminescence have been reported (156,165). 

The reaction of methoxy-substituted 1,4-dihydroatomatic systems is a general one. Other condensed systems react ia a similar manner, for example, 3,6-dimethoxy-1,4,S,8-tetrahydronaphtha1ene and derivatives of anthracene (35) and xanthene (36) (74). The proposed method enables synthesis of the tri-and tetracarbocyanines where the whole chromophore is iategrated iato a rigidizing skeleton. Asymmetrical polymethines can also be obtained similarly. 

In the dyestuff industry, anthraquinone still ranks high as an intermediate for the production of dyes and pigments having properties unattainable by any other class of dyes or pigments. Its cost is relatively high and will remain so because of the equipment and operations involved in its manufacture. As of May 1991, anthraquinone sold for 4.4/kg in ton quantities. In the United States and abroad, anthraquinone is manufactured by a few large chemical companies (62). At present, only two processes for its production come into consideration manufacture by the Friedel-Crafts reaction utilizing benzene, phthahc anhydride, and anhydrous aluminum chloride, and by the vapor-phase catalytic oxidation of anthracene the latter method is preferred. 

The addition product, C QHgNa, called naphthalenesodium or sodium naphthalene complex, may be regarded as a resonance hybrid. The ether is more than just a solvent that promotes the reaction. StabiUty of the complex depends on the presence of the ether, and sodium can be Hberated by evaporating the ether or by dilution using an indifferent solvent, such as ethyl ether. A number of ether-type solvents are effective in complex preparation, such as methyl ethyl ether, ethylene glycol dimethyl ether, dioxane, and THF. Trimethyl amine also promotes complex formation. This reaction proceeds with all alkah metals. Other aromatic compounds, eg, diphenyl, anthracene, and phenanthrene, also form sodium complexes (16,20). 

Hydrogen and sodium do not react at room temperature, but at 200—350°C sodium hydride is formed (24,25). The reaction with bulk sodium is slow because of the limited surface available for reaction, but dispersions in hydrocarbons and high surface sodium react more rapidly (7). For the latter, reaction is further accelerated by surface-active agents such as sodium anthracene-9-carboxylate and sodium phenanthrene-9-carboxylate (26—28). 

Few isothiazoles undergo simple cycloaddition reactions. 4-Nitroisothiazoles add to alkynes (see Section 4.17.7.4). With 5-thiones (84) and dimethyl acetylenedicarboxylate, addition to both sulfur atoms leads to 1,3-dithioles (85) (77SST(4)339, 80H(14)785, 81H(16)156, 81H(16)595). Isothiazol-3-one 1-oxide and the corresponding 1,1-dioxide give normal adducts with cyclopentadiene and anthracene (80MI41700), and saccharin forms simple 1 1 or 1 2 adducts with dimethyl acetylenedicarboxylate (72IJC(B)881). 

Quino[3,2-c][l,8]naphthyridine — see 4,5,12-Triazabenz[a]anthracenes Quinone, a-tocopheryl-synthesis, 3, 734 o-Quinone allides synthesis, 3, 741 o-Quinone diazides reactions... 

A more complex reaction model was proposed from the results of a kinetic study of thermal liquefaction of subbituminous coal. Data were obtained over a temperature range of 673 to 743 K (752 to 878°F) at 13.8 MPa (2000 psia) by using two solvents, hydrogenated anthracene oil (HAO), and hydrogenated phenanthrene oil (HPO), at a coal-solvent ratio of 1 15. Results were correlated with the following model ... 

The synthetic procedure described is based on that reported earlier for the synthesis on a smaller scale of anthracene, benz[a]anthracene, chrysene, dibenz[a,c]anthracene, and phenanthrene in excellent yields from the corresponding quinones. Although reduction of quinones with HI and phosphorus was described in the older literature, relatively drastic conditions were employed and mixtures of polyhydrogenated derivatives were the principal products. The relatively milder experimental procedure employed herein appears generally applicable to the reduction of both ortho- and para-quinones directly to the fully aromatic polycyclic arenes. The method is apparently inapplicable to quinones having an olefinic bond, such as o-naphthoquinone, since an analogous reaction of the latter provides a product of undetermined structure (unpublished result). As shown previously, phenols and hydro-quinones, implicated as intermediates in the reduction of quinones by HI, can also be smoothly deoxygenated to fully aromatic polycyclic arenes under conditions similar to those described herein. 

This trend is revealed, for example, by the rates of Diels-Alder addition reactions of anthracene, naphthacene, and pentacene, in which three, four, and five rings, respectively are linearly fused. The rate data are shown in Table 9.3. The same trend can be seen in the activation energy and the resonance energy gained when cycloreversion of the adducts 9-12 yields the aromatic compoimd, as shown in Scheme 9.3. 

Both phenanthrene and anthracene have a tendency to undergo addition reactions under the eonditions involved in eertain eleetrophilic substitutions. For example, in the nitration of anthracene in the presence of hydrochloric acid, an intermediate addition product can be isolated. This is a result of the relatively close balance in resonance stabilization to be regained by elimination (giving an anthracene ring) or addition (resulting in two benzenoid rings). 

Desvergne and Bouas-Laurent have shown that photochemical ring closure of a bis-anthracene bridged by a polyether chain is effective only when lithium cation is present . They presume that cyclization is successful because the conformation is cation locked . The reaction is shown in Eq. (2.6). 

Aryl bromides were also perfluoroethylated under these conditions [205] The key to improved yields was the azeotropic removal of water from the sodium perfluoroalkylcarboxylate [205] Partial success was achieved with sodium hepta-fluorobutyrate [204] Related work with halonaphthalene and anthracenes has been reported [206 207] The main limitation of this sodium perfluoroalkylcarboxylate methodology is the need for 2 to 4 equivalents of the salt to achieve reasonable yields A trifluoromethylcopper solution can be prepared by the reaction of bis(tri-fluoromethyl)mercury with copper powder in /V-methylpyrrolidone (NMP) at 140 °C [208] (equation 138) or by the reaction of N-trifluoromethyl-A-nitro-sotnfluoromethane sulfonamide with activated copper in dipolar aprotic solvents [209] This trifluoromethylcopper solution can be used to trifluoromethylate aro matic [209], benzylic [209], and heterocyclic halides [209]... 

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