Anthracene 1,2-oxide

P. J. van Bladeren, J. M. Sayer, D. E. Ryan, P. E. Thomas, W. Levin, D. M. Jerina, Differential Stereoselectivity of Cytochrome P450b and P450c in the Formation of Naphthalene and Anthracene 1,2-Oxides. The Role of Epoxide Hydrolase in Determining the Enantiomer Composition of the 1,2-Dihydrodiols Formed ,. /. Biol. Chem. 1985, 260, 10226- 10235. 

Naphthalene 1,2-oxide (136), a non-K-region epoxide, shows low thermal stability. Anthracene 1,2-oxide, on the other hand, is stable at ambient temperatures for several weeks. Preparation of (+ )-(lR,2S)-anthracene 1,2-oxide (137), using the above method, constitutes the first example of preparation of an optically pure arene oxide. However, the non-K-region oxides of phenanthrene, namely, its 1,2- and 3,4-oxides (47 and 48), obtained from chiral precursors, racemize fast.66 Perturbational molecular orbital calculations indicate that epoxide-oxepin valence tautomerism is possible. However, the oxepin could not be detected by NMR. 

Boyd and co-workers interest in the properties of arene oxide metabolites has led them to undertake investigations into the synthesis and isomerization of such compounds (e.g., dibenz[ , ]anthracene 3,4-oxide 27, phenanthrene 3,4-oxide 28, triphenylene 1,2-oxide 29, and dibenz[ ,f]anthracene 1,2-oxide 30 (Figure 4)) <2001J(P1)1091>. 

Arene oxides continue to excite interest because of their carcinogenic and mutagenic potential and a number of syntheses of such compounds have been reported during 1979. The synthesis of cyclopenta[cJ]pyrene 3,4-epoxides from the parent hydrocarbon has been achieved using a procedure which should be applicable to epoxidation of a range of other arenes (Scheme 16). Chrysene epoxides are available by essentially conventional syntheses. The synthesis of (+)- and (—)-naphthalene and anthracene 1,2-oxides has been described. The... 

It may be mentioned briefly that also for other catalytic oxidations, e.g., for those of ethylene and of anthracene, multicomponent catalysts proved to be very effective. For the anthracene oxidation, the following... 

Activation energies and pre-exponential factors for the first-order rate coefficients for anthracene oxidation... 

Figure 8 Schematic representation of binding interactions of aiene oxides at the H site of GST A, (4R,5S -benzo[a]pyrene oxide B, (5S,6R)-benzo[a]anthracene oxide C, (4R,5S)-pyiene oxide D, (7S)-styrene oxide, and E, (7R)-styrene oxide. (Taken from Dostal et al., 1986.)...

While the overall reaction of anthracene oxidation to form anthra-quinone as shown above involves the interaction of three atoms of oxygen per molecule of hydrocarbon, the actual mechanism of the catalysis is more or less obscure. From the observations of Senseman and Nelson86 the vanadium oxide catalysts function by being alternately reduced to a lower oxide by the hydrocarbon and oxidized to the pentoxide by the oxygen of the air used. Thus ... 

Electra-organic synthesis Chlorination of substituted naphthalenes. Toluene and aromatic hydrocarbon oxidation using Ce as a redoxmediator. Anthracene oxidation to anthraquinone using Mn as the redox medi ator. Forsyth et al. (1987) Pletcher Valdez (1988a,b) Chou etal. (1992)... 

The optically active benz[a]anthracene oxides (89) and (90) have been synthesized. Thermal recemization (at 293-322 K, in CDCI3) of the chiral chrysene 3,4-oxide (91) has been shown to occur via first-order kinetics, with an activation energy of 25.2 kcal mol" The results are consistent with a reaction mechanism involving an oxepine intermediate (92), as predicted by theory. 

The increasing importance of electron-transfer reactions with increasing aromatic hydrocarbon size is illustrated in the reaction of bromine with various aromatic compounds. With benzene (with a Lewis acid) and with naphthalene, electrophilic substitution occurs, and with anthracene, oxidative addition occurs (6) however, with graphite, only oxidation to the exclusion of carbon-bromine bond formation occurs, even at a stoichiometry of C8Br (II, 12). 

Methylnaphthalene is commonly used as a feedstock in the production of vitamia K3 (menadione). Methylnaphthalene is oxidized to menadione with chromic or nitric acid, in a similar method to anthracene oxidation. Menadione is used as an intermediate in the production of vitamin Ki.To produce vitamin Ki, menadione is reduced with hydrogen on Pd/activated-carbon catalysts to mena-diol. Esterification of the two hydroxyl groups with acetic anhydride yields mena-diol diacetate, which is converted into the 1-monoacetate with ammonia. Vitamin Ki (phytomenadione) is produced by the reaction of 1-menadiol monoacetate with phytol, using a BF3/ether complex as catalyst, followed by hydrolysis and dehydrogenation. 

Because of adequate availability of anthracene, oxidation is preferred to synthesis, but the latter can, however, be advantageous when substitution is required in specific positions. 

Technically-pure anthracene, containing around 95%, is used as feedstock for anthracene oxidation it is vaporized with the injection of steam and pre-heated... 

SCHEME 14.7 Anthracene oxidation via electron transfer-oxygenation mechanism (Elaborated from Ref. [38]). 

Anthraqiiinone may also be prepared by the oxidation of pure anthracene with a solution of chromium trioxide in glacial acetic acid ... 

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). 

Scintillation detectors are substances which fluoresce when stmck by x-radiation. Scintillation can, therefore, serve to convert x-ray photons into visible or ultraviolet light. Scintillation materials include thaUium-activatedcrystals of sodium iodide, NaI(Tl), potassium iodide, KI(T1), or cesium iodide, CsI(Tl) crystals of stilbene (a, P-diphenylethylene) [588-59-0] and anthracene [120-12-7] bismuth germanium oxide [12233-56-6] ... 

---