Anthracene anthrone

If the 9,10-dihydro-9-anthranyl carbanion were to react directly with oxygen, 9,10-dihydro-9-anthranylhydroperoxide would be formed. This could decompose to give anthrone and/or anthracene. Anthrone, which would exist mainly as anthranol in a basic medium, generally is oxidized easily to anthraquinone. The following equations illustrate this reaction. 

Reduction of anthraquinone gives dianthryl, anthrone and finally anthracene. 

Nitroanthrone has been prepared by the nitration of anthracene in isobutyl alcohol,1 and by the nitration of anthrone.2... 

Bei inverser Zugabe von Natriumboranat erhalt man aus Anthron 91% d.Th. 9,10-Dihydro-anthracen. 

Lengthening the side chain produces the antidepressant maprotiline (73), which has a topological relationship to the clinically useful tricyclic antidepressants. The requisite acid is constructed by conjugate addition of the carbanion of anthrone (64) to acrylonitrile, followed by hydrolysis to give 70. Reduction of the carbonyl group with zinc and ammonia gives anthracene 71 by dehydration of the intermediate... 

In pulp and paper processing, anthraquinone (AQ) accelerates the delignification of wood and improves liquor selectivity. The kinetics of the liquid-phase oxidation of anthracene (AN) to AQ with NO2 in acetic acid as solvent has been studied by Rodriguez and Tijero (1989) in a semibatch reactor (batch with respect to the liquid phase), under conditions such that the kinetics of the overall gas-liquid process is controlled by the rate of the liquid-phase reaction. This reaction proceeds through the formation of the intermediate compound anthrone (ANT) ... 

Moro-Oka et al. (1976) have reported that the oxidation of 9,10-dihydroanthracene by K02 solubilized in DMSO by 18-crown-6 gives mainly the dehydrogenated product, anthracene. Under the same conditions, 1,4-hexadiene is dehydrogenated to benzene. The authors proposed a mechanism in which the superoxide ion acts as a hydrogen-abstracting agent only. The oxidations of anthrone (to anthraquinone), fluorene (to fluorenone), xanthene (to xanthone) and diphenylmethane (to benzophenone) are also initiated by hydrogen abstraction. 

This aldehyde synthesis is applicable to compounds of the aromatic series having a labile hydrogen atom (phenyl ethers,1 naphthols,2 dialkylanilines,3-4 naphthostyril,2 anthrones 2) and to certain hydrocarbons of requisite reactivity (anthracene,5-6 7 1,2-benzanthracene,6 3,4-benzpyrene,3 7 pyrene,8 styrene,9 and a, a-diarylethylenes 9). With polynuclear hydrocarbons the best results are secured by the use of a solvent such as o-dichloro-benzene. 9-Anthraldehyde has also been prepared by the action of hydrogen cyanide and aluminum chloride on anthracene in chlorobenzene.10... 

Avery, M. L., Humphrey, J. S., and Decker, D. G. (1997). Feeding deterrence of anthra-quinone, anthracene, and anthrone to rict-toxmgbirAs.JournalofWildlifeManagement 61, 1359-1365. 

Anthrone did not react with DMSO under the reaction conditions. However, 9,10-anthraquinone (2 mmoles) in 25 ml. of DMSO (80%)-terf-butyl alcohol (20% ) containing potassium tert-butoxide (4 mmoles) gave a deep red solution at 25°C., from which 60% of the adduct could be isolated after 1 hour and 88% after 3 hours. This adduct was isolated from the oxidate of 9,10-dihydroanthracene (after hydrolysis, acidification, and filtrations of anthracene) by extraction of the aqueous filtrate by chloroform. Xanthone and thioxanthone failed to form isoluble adducts with DMSO in basic solution. 

The autoxidation mechanism by which 9,10-dihydroanthra-cene is converted to anthraquinone and anthracene in a basic medium was studied. Pyridine was the solvent, and benzyl-trimethylammonium hydroxide was the catalyst. The effects of temperature, base concentration, solvent system, and oxygen concentration were determined. A carbanion-initi-ated free-radical chain mechanism that involves a singleelectron transfer from the carbanion to oxygen is outlined. An intramolecular hydrogen abstraction step is proposed that appears to be more consistent with experimental observations than previously reported mechanisms that had postulated anthrone as an intermediate in the oxidation. Oxidations of several other compounds that are structurally related to 9,10-dihydroanthracene are also reported. 

A sample of the monohydroperoxide, previously reported by Bickel and Kooyman (2), was obtained by autoxidation of 9,10-dihydroanthra-cene in benzene under ultraviolet irradiation. When this compound was treated under nitrogen with benzyltrimethylammonium hydroxide, it decomposed to give a mixture of anthracene and anthrone. (Under acidic conditions, it decomposed entirely to anthracene.) A fresh sample of the hydroperoxide was then oxidized. The physical appearance of the reaction mixture was similar to that in the oxidation of anthrone. The product was analyzed, and the conversion to anthraquinone was only 59%. Again, other oxidation products or anthrone may have contributed to the anthraquinone estimate. 

The direct reaction of oxygen with the carbanion from dihydroanthracene does not seem likely. Russell (5) has indicated a preference for a one-electron transfer process to convert the carbanion to a free radical, which then reacts with oxygen to form an oxygenated species. Therefore, we considered a mechanism involving one-electron transfer to form a free radical from the carbanion, which would lead to the formation of anthraquinone and anthracene without having either the hydroperoxide or anthrone as an intermediate. 

The hrst step in the preparation of the antidepressant maprotiline (33-5) takes advantage of the acidity of anthrone protons for incorporation of the side chain. Thus treatment of (30-1) with ethyl acrylate and a relatively mild base leads to the Michael adduct saponihcation of the ester group gives the corresponding acid (33-1). The ketone group is then reduced by means of zinc and ammonium hydroxide. Dehydration of the hrst-formed alcohol under acidic conditions leads to the formation of fully aromatic anthracene (33-2). Diels-Alder addition of ethylene under high pressure leads to the addition across the 9,10 positions and the formation of the central 2,2,2-bicyclooctyl moiety (33-3). The hnal steps involve the construction of the typical antidepressant side chain. The acid in (33-3) is thus converted to an acid chloride and that function reacted with methylamine to form the amide (33-4). Reduction to a secondary amine completes the synthesis of (33-5) [33]. 

Hoestery, D. C., and G. M. Letson Trapping of photocarriers in anthracene by anthraquinone, anthrone and naphthacene. J. Phys. Chem. Solids 24,1609 (1963). 

Photochemical isomerizations by intramolecular 4n + An cycloaddition of carbon oxygen linked bichromophoric anthracenes to give oxetane derivatives have not been reported yet. Upon irradiation (X > 400 nm) in either toluene or ethyl acetate, the methoxycarbonyl substituted carbon oxygen linked bichromophoric anthracene 14 indeed isomerizes smoothly and efficiently (cp — 0.45). However, the two products, obtained in an approximate ratio of 5 1, are anthrone derivatives 15 and 16 whose formation can be rationalized by migration of the anthryloxy moiety [60], An analogous photolytic rearrangement has been found for 9-anthryloxy substituted dianthrylethylenes (see Section III.A). 

The 1,4-addition of heterocycles to aromatic systems has been reported. Photolysis of piperidine in benzene, for example, leads to the formation of the -substituted piperidine (222).204 Pyrrole, on photolysis in benzene, behaves differently and yields the 2-substituted pyrrole (223).208 In both instances, excitation of benzene, probably to the triplet, appears to be the initial step in the photolysis. The photolysis of iV-nitrosopiperidine in the presence of anthracene also results in 1,4-addition and the formation of an anthrone oxime,... 

TL4391). The benzologs of naphtho[bc]furan-6-ones 60 (so-called furan-anthrones) are obtained by cyclization of anthracene peri-hydroxy ketones 58 or carbomethoxychloromethylanthraquinones 59 (80MI3 84ZOR818). 

Significant impact on the environment and generation of wastes (mainly associated with the less than 100% selectivity in the reduction and oxidation steps - formation ofhydroxyanthrones, anthrones, anthracenes, and epoxide, some solvent stripping by air used in the oxidation step, and in the crude H202 stream). 

Quinones of the more reactive, polycyclic, aromatic systems can usually be obtained by direct oxidation, which is best carried out with chromium(vi) compounds under acidic conditions. In this way 1,4-naphthoquinone, 9,10-anthraquinone and 9,10-phenanthraquinone are prepared from naphthalene, anthracene and phenanthrene respectively (Expt 6.128). Also included in this section is the reduction of anthraquinone with tin and acid to give anthrone, probably by the sequence of steps formulated below. 

X-ray irradiation of single crystals of anthracene peroxide (33, Scheme 23) gives mixed crystals of anthraquinone (34) and anthrone (35), with retention of the shape of the original crystal [118]. This transformation has been monitored by... 

Other methods to reduce polycyclic quinones to arenes that have met with some success include SnCU/HCl, 58 Zn/NH3, 59Zn/pyridine/MeC02H, NaBH4/BF3-Et20, 6 and NaBH4 in MeOH. All of these methods are compatible with aryl halides and the latter two are also compatible with aryl ethers, anilines and phenols. lO-Arylmethylene-9-anthrones have also been reduced to anthracenes with dibo-rane (Scheme 75). ... 

Reduction of anthrone to anthracene is accomplished by refluxing in aqueous sodium hydroxide solution with activated zinc dust. The method has the merit of affording pure, beautifully fluorescent anthracene. 

Chemical and biochemical reactions can be viewed by diffraction methods provided the reactions are slow and the techniques for measuring them are rapid. For example, Lonsdale and coworkers studied the conversion of a photo-oxide of anthracene on exposure to Cu Ka or Mo Ka X rays at room temperature. A single mixed crystal of anthraquinone and anthrone is formed which still shows crystallinity. The crystal does not change in appearance, and the space group remains P2i/a, but the unit-cell dimensions change ... 

Lonsdale, K., Nave, E., and Stephens, J. F. X-ray studies of a single crystal chemical reaction photooxide of anthracene to (anthraquinone, anthrone). Phil. Trans. Roy. Soc. (London) A26, 1-31 (1966). 

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