9 : 10-Dihydroanthracene

In a 2-1., three-necked, round-bottomed flask fitted with a rubber-tube sealed mechanical glass stirrer, a reflux condenser (Note 1), and a thermometer reaching to the bottom of the flask are placed 50 g. (0.28 mole) of anthracene (Note 2) and 750 ml. of commercial absolute ethanol. The suspension obtained is stirred and heated (Note 3) to 50°, and 75 g. (3.25 g. atom) of freshly cut sodium is added in quantities of about 10 g. each to the stirred mixture over a period of 5 minutes. The reaction mixture boils vigorously (Note 4) and stirring is continued for 15 minutes longer. The reaction mixture is then cooled and carefully diluted with 1 1. of water. The white-yellow solid which separates is a mixture of 9,10-dihydroanthracene and anthracene, and it is collected on a Buchner fimnel, washed with 400 ml. of water, and dried in air. 

The dry white-yellow solid is suspended in 500 ml. of commercial absolute ethanol in a 1-1., three-necked, round-bottomed flask fitted with a rubber-tube sealed mechanical glass stirrer, a reflux condenser (Note 1), and a thermometer reaching to the bottom of the flask. The suspension is stirred and heated (Note 

3) to 50°, and 50 g. (2.17 g. atom) of freshly cut sodium is added in quantities of about 10 g. each to the stirred mixture over a period of 5 minutes. The reaction mixture boils vigorously (Note 

An efficient 12-in., double-surface, all-glass condenser should be used with an outlet tube carrying the evolved hydrogen into a good hood vent. 

A purified grade of anthracene (blue fluorescence, m.p. 216°) should be used. 

A solution of 157 g. (1.20 moles) of 3-diethylamino-1-propanol in 260 ml. of chloroform is added (1 hour) to an ice-cold solution of 290 g. (2.44 moles) of thionyl chloride in 1200 ml. of chloroform. The reaction mixture is heated under reflux for 3 hours, after which the solvent and excess thionyl chloride are distilled off and the solid residue made alkaline with 40% aqueous sodium hydroxide solution. The reaction mixture is cooled during the addition of the alkali. Ether extraction followed by distillation of the extracts gives 131 g. (73%) of colorless oil boiling at 73-75°/20 mm. The hydrochloride (prepared by passing dry hydrogen chloride through an ether solution of the oil) is a white powder, m.p. 66-68°. The free base is unstable and should be stored in a refrigerator. 

A suspension of 17.8 g. (0.10 mole) of anthracene (for purification of anthracene see under anthroic acid, p. 23) in 200 ml. of liquid ammonia is stirred vigorously while 4.6 g. (0.20 gram atom) of freshly cut sodium metal is added in small pieces over a 30-minute period. 

6-Dihydroxy-4-methylbenzaldehyde, m.p. 178-180°, may be obtained in the same manner and 85% yield from orcinol (p. 240). 

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The secular equation for 1,2-dihydroanthracene resulting from the consideration of (I) the symmetrical unexcited structure, (II) the two unsymmetrical unexcited structures, (III) the sixteen first-excited structures not involving conjugation of the double bond and the naphthalene nucleus, and (IV) the six first-excited structures involving this conjugation, is... 

Boyd, D.R., N.D. Sharma, R. Agarwal, R.A.S. McMordie, J.G.M. Bessems, B. van Ommen et al. (1993). Biotransformation of 1,2-dihydronaphtha-lene and 1,2-dihydroanthracene by rat liver microsomes and purified cytochromes P-450. Formation of arene hydrates of naphthalene and anthracene. Chem. Res. Toxicol. 6, 808-812. 

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. 

Anthracene and maleic anhydride. In a 50 ml. round-bottomed flask fitted with a reflux condenser, place 2 0 g. of pure anthracene, I 1 g. of maleic anhydride (Section 111,93) and 25 ml. of dry xylene. Boil the mixture under reflux for 20 minutes with frequent shaking during the first 10 minutes. Allow to cool somewhat, add 0 5 g. of decolourising carbon and boil for a further 5 minutes. Filter the hot solution through a small, preheated Buchner funnel. Collect the solid which separates upon coohng by suction filtration, and dry it in a vacuum desiccator containing paraffin wax shavings (to absorb traces of xylene). The yield of adduct (colourless crystals), m.p. 262-263° (decomp.), is 2-2 g. Place the product (9 10-dihydroanthracene-9 10-cndo-ap-succinic anhydride) in a weU-stoppered tube, since exposure to air tends to cause hydration of the anhydride portion of the molecule. 

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). 

Laudanosine contains four methoxyl groups. By exhaustive methyla-tion it yields trimethylamine and laudanosene (tetramethoxy-o-vinyl-stilbene), CH2=CH—C6H2(OCH3)2—CH=CH—C6H3(OCH3),. On oxidation with manganese dioxide and sulphuric acid it furnishes, in addition to the interesting by-product 2 3 6 7-tetramethoxy-9 10-dihydroanthracene, veratraldehyde and 4 5-dimethoxy-2 )3-methyl-... 

WittigdaZ. have shown that henzyne (111) reacts as a dienophile wdth 2-methyl-and 2-phenylisoindole to give bridged dihydroanthracenes (112,. R = CH3,C6H5). 

The reaction of benzyl radicals wdth several heterocyclic compounds W as more extensively studied by Waters and Watson, " - who generated benzyl radicals by decomposing di-tert-butyl peroxide in boiling toluene. The products of the reaction with acridine, 5-phenyl-acridine, 1 2- and 3 4-benzacridine, and phenazine were studied. Acridine gives a mixture of 9-benzylacridine (17%) (28) and 5,10-dibenzylacridan (18%) (29) but ho biacridan, w hereas anthracene gives a mixture of 9,10-dibenzyl-9,10-dihydroanthracene and 9,9 -dibenzyl-9,9, 10,10 -tetrahydrobianthryl. This indicates that initial addition must occur at the meso-carbon and not at the nitrogen atom. (Similar conclusions were reached on the basis of methylations discussed in Section III,C.) That this is the position of attack is further supported by the fact that the reaction of benzyl radicals with 5-... 

Under the phase-transfer catalysis conditions, 2-bromo-8-methylquino-line (67) was coupled with 2-pyridylboronic ester 68 to furnish 2-(2-pyridyl)-8-methylquinoline (69) in 56% yield (91JOC6787). At this point, it is opportune to mention that the simple 2-pyridylborane, in contrast to 3- and (4-pyridyl)boranes, is considered an unsuitable Suzuki coupling partner because it forms an unusually stable cyclic dimer resembling a dihydroanthracene. In this case, the obstacle was circumvented by using 2-pyridylboronic ester in place of 2-pyridylborane (Scheme 9). 

Blackley548 measured the rates of deuteration of biphenylene, fluorene, tri-phenylene, and phenanthrene relative to o-xylene as 6.15 5.85 1.08 1.32, which is in very good agreement with the values of 8.80 7.00 - 1.14 which may be deduced from the detritiation data in Table 159, obtained using anhydrous trifluoroacetic acid. Aqueous trifluoroacetic acid (with the addition in some cases of benzene to assist solubility) was used by Rice550, who found that triptycene was 0.1 times as reactive per aromatic ring as o-xylene (cf. 0.13 derivable from Table 159) whereas the compound (XXXI) was 0.9 times as reactive as o-xylene. An exactly comparable measure is not available from Table 158, but dihydroanthracene (XXXII), which is similar, was 0.51 times as reactive as o-xylene and... 

The quantum-mechanical treatment previously applied to benzene, naphthalene, and the hydrocarbon free radicals is used in the calculation of extra resonance energy of conjugation in systems of double bonds, the dihydro-naphthalenes and dihydroanthracenes, phenylethylene, stilbene, isostilbene, triphenylethylene, tetraphenylethyl-... 

Anhydro-2l3-dideoxy-2,3-(9,10-dihydroanthracene-9I10-diyl)-P-D-ribo-... 

NXHOMO of the hydroxy-substituted dihydroanthracene is also symmetric in sign. Therefore, the antisymmetric orbital does not interact significantly with these vacant n orbitals of 36, resulting in an unperturbed n face of the carbonyl it orbital. This motif is regarded as an example of orbital non-interaction [105], Thus, the reduction of 2-methoxy and 3-methoxydibenzobicyclo[2.2.2]octadienones (34c and 34f) should intrinsically show little or no bias. 

Akhtar MN, DR Boyd, NJ Thompson, M Koreeda, DT Gibson, V Mahadevan, DM Jerina (1975) Absolute stereochemistry of the dihydroanthracene-ci - and -fra 5,l,2-diols from anthracene by mammals and bacteria. J Chem Soc Perkin I 2506-2511. 

C-NMR. The structures of the leuco derivatives of l,4-bis(butylamino)-anthraquinone (14) and l-butylamino-4-hydroxyanthraquinone (15) have been shown to be l,4-bis(butylamino)-2,3-dihydroanthracene-9,10-dione (16a) and l-butylamino-10-hydroxy-2,3-dihydroanthracene-4,9-dione (17a), respectively. On the other hand, leuco-1,4-dimethoxyanthraquinone has been assigned the structure, 1,4-dimethoxy-9,10-dihydroxyanthracene (18). 

In some model compound studies with the i-PrOH/KOH system we found that anthracene was converted to 9,10-dihydroanthracene in 64% yield. Benzyl phenyl ether was also studied and was converted to a polymeric material under the reaction conditions. There were no traces of phenol nor toluene, the expected reduction products. 

Model compound studies were also carried out in MeOH/KOH, and the results are shown in Table VI. Phenanthrene and biphenyl were quantitatively recovered unchanged by the reactions, and bibenzyl was recovered in 95% yield, with small amounts of toluene observed. Anthracene and diphenyl ether, on the other hand, were converted respectively to 9,10-dihydroanthracene and a mixture of polymethyl-phenols similar to that observed in the work with coal. The cleavage of diphenyl ether via hydrogenolysis should yield both benzene and phenol as products we saw no benzene in our study, and our... 

Experimental results are shown in Table 1.2, which quotes the observed percentage conversion of each of the model C14 substrates to their di-hydro derivatives by each of the model CIO solvents. Consider first the column for the anthracene substrate, showing its conversion to 9,10 dihydroanthracene after 2 hr at 300 C in various solvents. The conversion by Q) (58%), is an order of magnitude greater than that by (5%), in striking... 

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