215-58-7 Dibenz anthracene

Sources. Dibenz[ ,/ ]anthracene (DBA) is a major component of polynuclear aromatic hydrocarbons, also known as polycyclic aromatic hydrocarbons, and is usually bound to small particulate matter present in urban air, industrial and natural combustion emissions, and cigarette smoke. 

Flesher JW, Horn J, Lehner AF Comparative carcinogenicity of picene and dibenz( , )anthracene in the rat. Biochem Biophys Res Commun 190 115-119, 2002... 

The use of soluble metal catalysts makes it possible to react 8 and its substituted derivatives with aryl bromides and triflates at 100 °C. The catalyst systems that have been used are Pd2(dba>3 and ( )BINAP with calcium carbonate as base (dba = dibenz[ ,. ]anthracene, BINAP = 2,2-bis(diphenyl-phosphanyl)-l,l-binaphthyl)<2000JA2178>, and 2-(di-r-butylphosphino)biphenyltris(dibenzylideneacetone)palladium with sodium yt-butoxide as base <2003T3109>. 

An interesting arylation of the silyl enolate of Ley s dioxanone 133 in the presence of a catalytic amount of Pd2(dba)3 (5 mol%) and P(/-Bu)3 (10 mol%) with 0.5 equiv of Znp2 or Zn(0-/-Bu)2 provides a single diastereoisomer of the coupled products 134 (dba = dibenz[ , ]anthracene). A variety of electronically and sterically distinct aryl halides, including those containing electrophilic functional groups, have been introduced (Equation 20) <2004JA5182>. 

The reaction of PhCH=C(CN)2 with the hydroxy allylic carbonate in the presence of catalytic amounts of Pd2dba3 in CHCI3 and (o-tolyl)3P in THF at 100°C gives the cycloaddition product, the oxepane, in 31% yield with low diastereoselectivity (dba = dibenz[ , ] anthracene) <2001JOC7142>. 

The reaction of cycloalkeno-l,2,3-selenadiazole 183 with a mixture of [Pd2(dba)3] and trialkylphosphine in toluene under reflux for 1 h gave the novel complexes 51 in 36-55% yields (dba = dibenz[ ] anthracene) <2004POL2967, 1998CC1305>. The molecular structure of complex 51 (n = 1, R = Bu) was determined by X-ray crystallography. The proposed mechanism is shown in Scheme 18. Insertion of palladium(O) into the selenium-nitrogen bond of 1,2,3-selenadiazole occurs, followed by 1,3-dipolar addition of a selenaketocarbene 185 formed in situ by thermal elimination of dinitrogen with the elimination of a trialkylphosphine. 

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>. 

Benz(ghi)perylene 1,2,5,6-dibenz anthracene C17-and up Aliphatics n-Octadecane n-Eicosane Not quantified ... 

Being interested here in the volatile components of coffee aroma, we shall arbitrarily limit the list of the aromatic hydrocarbons to tricyclic structures. The higher fused polycyclic hydrocarbons (fluoranthene [206-44-0], pyrene [129-00-0], chrysene [218-01-9], benz[ ]anthracene (1,2-benzanthracene) [56-55-3], benz[< ]acephenanthrylene (3,4-benzofluoranthene) [205-99-2], benzo[ ]pyrene (3,4-benzopyrene, 3,4-BP) [50-32-8], benzo[e]pyrene (1,2-benzopyrene) [192-97-2], perylene [198-55-0], benzo[g,/i,/]perylene (1,12-benzopyrene) [191-24-2], and dibenz[ ,//]anthracene (1,2,5,6-dibenzanthracene) [53-70-3]) cannot be considered as a part of the aroma. However, as some of these, specially benzo[o pyrene, are known for carcinogenic properties, they have been particularly analyzed in food subject to roasting or smoke-curing. 

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. 

Dibenz[yellow-green colour (due to other pentacyclic impurities) has been removed by crystn from benzene or by selective oxidation with lead tetraacetate in acetic acid [Moriconi et al. J Am Chem Soc 82 3441 7960]. 

Coke (coal tar), high temperature pitch Coke (coal tar), mixed coal-high temperature pitch Coke (coal tar), low temperature, high temperature pitch Diaminotoluene o-Dianisidine Salts of o-dianisidine o-Dianisidine-based azodyes Diarsenic trioxide Diazomethane Dibenz(a,/i)anthracene 1,2-Dibromo-3-chloropropane... 

DIAZINON AG 600 WBC , diazinon, 50 DIAZOL , diazinon, 50 Diazomethane, 50 Dibenz(a,h)anthracene, 50 Dibenzofuran, 51 DIBK, 51 Diborane, 51 DIBROM , naled, 51 Dibromobenzene, 51 Dibromochloromethane, 51... 

The fluorescence spectrum of dibenz[7>,/]oxepin shows that this molecule adopts a planar structure in the excited state whereas the ground state has bent geometry as expected.19 The emission spectrum is similar to that of anthracene. 

Note Bi, biphenyl Nap, naphthalene Phe, phenanthrene Anth, anthracene Hu, fluoranthene Pyr, pyrene Chr, chrysene BaAnth, benz[a]anthracene BaPyr, benzo[a]pyrene BbFlu, benzo[h]fluoranthene DBaAnth, dibenz[a,/i]anthracene 3-Me-Chol, 3-methylcholanthrene. 

Juhasz AL, ML Britz, GA Stanley (1997) Degradation of benzo[a]pyrene, dibenz[(3,/j]anthracene and coronene by Burkholderia cepacia. Water Sci Technol 36 45-51. 

The biodegradation of pyrene, chrysene, fluoranthene, benz[a]anthracene, dibenz[a,/t] anthracene, benzo[a]pyrene, and coronene by Stenotrophomonas maltophilia has been studied in the presence of a range of synthetic surfactants (Boonchan et al. 1998). Nonneutral surfactants were toxic, biodegradation was also inhibited by the neutral Igepal CA-630, and the positive enhancement of removal of substrates was generally low—in the range of 10%. 

Coman et al. [82] used a new modeling of the chromatographic separation process of some polar (hydroxy benzo[a]pyrene derivatives) and nonpolar (benzo[a]pyrene, dibenz[a,/ ]anthracene, and chrysene) polycyclic aromatic compounds in the form of third-degree functions. For the selection of the optimum composition of the benzene-acetone-water mobile phase used in the separation of eight polycyclic aromatic compounds on RP-TLC layers, some computer programs in the GW-BASIC language were written. 

The most significant differences (i.e. independence) in the analytical methods are provided in the final chromatographic separation and detection step using GC/ MS and LC-FL. GC and reversed-phase LG provide significantly different separation mechanisms for PAHs and thus provide the independence required in the separation. The use of mass spectrometry (MS) for the GC detection and fluorescence spectroscopy for the LG detection provide further independence in the methods, e.g. MS can not differentiate among PAH isomers whereas fluorescence spectroscopy often can. For the GC/MS analyses the 5% phenyl methylpolysiloxane phase has been a commonly used phase for the separation of PAHs however, several important PAH isomers are not completely resolved on this phase, i.e. chrysene and triphenylene, benzo[b]fluoranthene and benzofjjfluoranthene, and diben-z[o,h]anthracene and dibenz[a,c]anthracene. To achieve separation of these isomers, GC/MS analyses were also performed using two other phases with different selectivity, a 50% phenyl methylpolysiloxane phase and a smectic liquid crystalline phase. 

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