Benzo naphthalene

Proton-proton coupling constants of benzo rings of benzazoles can illuminate the bonding in such compounds. Thus, comparison of the J values for naphthalene with those for benzotriazoles of different types (Table 13) shows evidence of bond fixation, particularly in the 2-methyl derivative (98) (71PMH(4)l2l). 

Solids. —It may Idc a hydrocM bon (c .g., paraffin wa, naphthalene) highei alcohol eg., cetyl alcohol) aldehyde e.g., z5-hydroxybenzaldehyde) ketone and qiiinonc e.g., benzo-phenone, camphor) acid (higher fatty, e.g., palmitic acid or aromatic acid) ester (of glycerol, phenols or aromatic alcohols) phenol e.g., thymol),... 

The benzo-annellated derivative naphtho[l,2-c]furoxan is numbered according to the system (2)] shown. In the literature the name 1,2-naphthofuroxan may often be found, with the same numbering as for a 1,2-disubstituted naphthalene. Although the latter method is perhaps a little clearer to follow, the more systematic scheme (2) will be adhered to in this chapter. 

Indications of the relative efficiencies of transmission through either aza or sulfur in benzo derivatives can be obtained from Jaffe s empirical multiple regression approach.In these systems, just as in aza-naphthalenes (Section IV,C, l,d), knowledge of the dissociation... 

Condensation of the dianion of 1,2-dimercaptobenzene (380) with 1-chloro-8-nitronaphthalene (483) in DMF provided 45% of benzo[2,3]naphthalene [5,6,7-/j][l,4]dithiepin (484) and a small amount of its 5-oxide 485 (Eq. 44) (89JHC667). Though the structure of 485 was adequately determined (NMR studies, X-ray crystallography), its formation was not definitely explained. 

Figure 1.4 Two-dimensional plot of HPLC (log /J and GC (log Iq) retention indexes (1) naphthalene (2) 2-methylnaphthalene (3) 2,3-dimethylnaphthalene (4) 2,3,6-trimethyl-naphthalene (5) biphenyl (6) fluorene (7) dibenzothiophen (8) phenanthrene (9) 2-methylphenanthrene (10) 3,6-dimethylphenanthrene (11) benzo[a]fluorene (12) chrysene (data replotted from reference (31)).

Besides a parent ion, the mass spectra of benzo- and dibenzothiepins show the corresponding naphthalene or phenanthrene radical cations as the base peak.2-16 The mass spectra of 1-benzo-thiepin 1-oxides and 1,1-dioxides show the same naphthalene radical cation, formed by loss of sulfur monoxide or sulfur dioxide, respectively.14 In contrast, in the mass spectrum of 2,7-di-terf-butylthiepin peaks resulting from the loss of sulfur are not found.17... 

The greater lability of 1-benzothiepin 1-oxides, compared to the parent compounds, may lead to differences in chemical behavior. Thus, treatment of the tricarbonyliron complex of 1-benzo-thiepin 1-oxide (8, X = SO) with ammonium cerium(IV) nitrate in acetone at — 30 °C leads, with the loss of sulfur monoxide, to naphthalene. In contrast, the iron ligand can be removed selectively from the corresponding 1-benzothiepin by ammonium cerium(IV) nitrate.23 92 For the synthesis of 1-benzothiepin 1-oxide, see Section 2.1.4.1,... 

Irradiation of 1-benzothiepins 1 in tetrahydrofuran with a high-pressure 450-W mercury lamp and a Pyrex filter at 0"C for four hours results in a reversal of the thiepin-synthesis method startingfrom 3,4-benzo-2-thiabicyclo[3.2.0]hept-3,6-dienes (see Section 2.1.3.3.), giving the photoproducts 2 along with some of the corresponding naphthalenes.1019... 

Benzo-l,2,3-triazin-4-ones with the general structure 6.54 (X = O, S, or H2) are obtained by diazotization of the appropriate aniline derivatives 6.53 (Scheme 6-38). In polar aprotic solvents (e. g., nitrobenzene) the reverse reaction takes place to give the diazonium ion (for an example see Kullick, 1966). Diazotization of 1,8-diamino-naphthalene yields l-i/-naphthol[l,8-cfe]triazine (6.55 Tavs et al., 1967). In concentrated HC1 the triazine ring is opened again. 

A kinetic study of dedeuteration at 25 °C yield the following rate coefficients for [2H]-C6H4R578> 579 (R = )4-Me, 1,900 2-Me, 530 3-Me, 2.7 4-Ph, 1,400 2-Ph, 260 3-Ph, < 0.2 2,3-benzo(l position of naphthalene) 20,000-30,000 and 3,4-benzo (2 position of naphthalene) 500. Rather surprisingly, the rates of dedeuteration were little different from the rates of deuteration and it should be noted that quoted partial rate factors in this work were obtained by dividing these rates for dedeuteration at 25 °C by the rates of deuteration of benzene at 20 °C and errors of a factor of 2 or more may be introduced by this. 

Hydrogen iodide has also been used as a catalyst for hydrogen exchange581, rate coefficients (lO7 ) at 25 °C for reaction with [2H]C6H4R being (R =) 2,3-benzo(l position of naphthalene), 500 4-Me, 40 2-Me, 21 4-Ph, 42 2-Ph, 10. The reaction was catalysed by added iodine, the rate being directly proportional to the concentration of this, and for the latter compound rates were measured... 

By introducing reasonable values (about 2 for nitrogen, 4 for oxygen) for the electron affinity parameter relative to carbon, 8, and for the induced electron affinity for adjacent atoms (32/8i = Vio), we have shown that the calculated permanent charge distributions for pyridine, toluene, phenyltrimethylammonium ion, nitrobenzene, benzoic acid, benzaldehyde, acetophenone, benzo-nitrile, furan, thiophene, pyrrole, aniline, and phenol can be satisfactorily correlated qualitatively with the observed positions and rates of substitution. For naphthalene and the halogen benzenes this calculation does not lead to results... 

Figure 3 depicts profiles of Total PAH fluxes vs. time (36). The following polycyclic hydrocarbons have been determined by high performance liquid chromatography, variable wavelength absorption detection Naphthalene, acenaphthylene, 7,12-dimethylbenzanthracene, 2-methylnaphtalene, fluorene, acenaphtene, phenanthrene, 2,3-dimethylnaphtalene, anthracene, fluoranthene, 1-methylphenanthrene, pyrene, 2,3-benzofluorene, triphenylene, benz(a)anthracene, chrysene, benzo(b)fluoranthene, benzo(k)fluoranthene, perylene, benzo(e)pyrene, 1,2,3,4-dibenzanthracene, benzo(a)pyrene, and 1,2,5,6-dibenzanthracene. 

Benzo[fl]- (a), benzo[fc]- (b) and benzo[c]flnorenes (c) bearing a diene group (93) in spiro geometry are three possible combinatorial isomers wherein the direction of fnsion of the naphthalene is different (Fig. 15). The n reaction centers of the diene gronps are snbject to spiro-conjngation [98, 99, 102] with the planar aromatic n system. The effect of perturbation arising from spiro-conjngation on... 

The structures of some PAHs of environmental interest are given in Figure 9.1. Naphthalene is a widely distributed compound consisting of only two fused benzene rings. It is produced commercially for incorporation into mothballs. Many of the compounds with marked genotoxicity contain 3-7 fused aromatic rings. Benzo[a] pyrene is the most closely studied of them, and will be used as an example in the following account. 

Turning to the acute toxicity of PAH, terrestrial organisms will be dealt with before considering aquatic organisms, to which somewhat different considerations apply. The acute toxicity of PAHs to mammals is relatively low. Naphthalene, for example, has a mean oral LD50 of 2700 mg/kg to the rat. Similar values have been found with other PAHs. LC50 values of 150 mg/kg and 170-210 mg/kg have been reported, for phenanthrene and fluorene, respectively, in the earthworm. The NOEL level for survival and reproduction in the earthworm was estimated to be 180 mg/ kg dry soil for benzo[a]pyrene, chrysene, and benzoMfluoranthene (Enviromnental Health Criteria 202). 

The photochemical transformation of phenanthrene sorbed on silica gel (Barbas et al. 1996) resulted in a variety of products including c -9,10-dihydrodihydroxyphenanthrene, phenanthrene-9,10-quinone, and a number of ring fission products including biphenyl-2,2 -dicarboxaldehyde, naphthalene-l,2-dicarboxylic acid, and benzo[c]coumarin. 

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. 

The transformation of benzene, toluene, naphthalene, biphenyl, and benzo[a]pyrene to the corresponding phenols (Trower et al. 1989) by Streptomyces griseus, and of phenanthrene by Streptomyces flavovirens to ( )tran5 -[95, 105 ]-9,10-dihydrodihydroxyphenanthrene with minor amounts of 9-hydroxyphenanthrene (Sutherland et al. 1990). 

A cytochrome P450 has been purified from Saccharomyces cerevisiae that has benzo[a]pyrene hydroxylase activity (King et al. 1984), and metabolizes benzo[fl]pyrene to 3- and 9-hydroxybenzo[fl]pyrene and benzo[fl]pyrene-7,8-dihydrodiol (Wiseman and Woods 1979). The transformation of PAHs by Candida Upolytica produced predominantly monohydroxyl-ated products naphth-l-ol from naphthalene, 4-hydroxybiphenyl from biphenyl and 3- and 9-hydroxybenzo[fl]pyrene from benzo[fl]pyrene (Cerniglia and Crow 1981). The transformation of phenanthrene was demonstrated in a number of yeasts isolated from littoral sediments and of these, Trichosporumpenicillatum was the most active. In contrast, biotransformation of benz[fl]anthracene by Candida krusei and Rhodotorula minuta was much slower (MacGillivray and Shiaris 1993). 

Extension of -conjugation from naphthalene to anthracene and phenanthrene has a small effect on the tmax of the photomerocyanine form. Replacement of the indoline ring with piperidine, benzoxazole, or benzo-thiazole83 has resulted in hypsochromic shift by ca. 10 nm.72... 

Firstly, the electronic effect of the substituents would be a dominant factor in the determination of the thermal stability of the thiepins. Thermal stability was found to decrease sharply with decreasing substitution. For example, the tri-substituted benzo-[6]thiepin (16 d) extrudes sulfur only when heated while the non-substituted benzo[ >]-thiepin (4) is readily converted into naphthalene and sulfur at 40 °C with a half-life of 80 min 41 >. 

Systematic studies on benzo[Z>]thiepin 1-oxides were reported by Hofmann and coworkers 82,83). 4-Phenylbenzo[6]thiepin 1-oxides 137a and 137b were prepared via the benzo[h] 3-thiepinone 1-oxide 138 as well as by direct oxidation of the benzo[b]thiepins 139a and 139b, The synthesis of 137c and 137d was only accomplished by the latter way. Further oxidation of 137 yielded the thermally stable 1,1-dioxides. Thermolysis of 137 produced the corresponding naphthalenes by... 

The benzo-derivative 16 is accessible through 1,4-dimethylnaphthalene, which on singlet oxygenation leads to the thermally labile naphthalene-1,4-endoperoxide. This endoperoxide expels singlet oxygen at ca. 10 °C, but diimide reduction below 0 °C in MeOH affords the stable dihydro derivative 16 (Eq. 11). 

A versatile and regioselective synthesis of benzo[b]furans, naphthalenes, indoles and benzothiophenes was achieved by reaction of o-alkynylarene and heteroarene carboxaldehyde derivatives in the presence of iodonium ions. The reaction mechanism was also discussed <06CEJ5790>. 

The naphthalene-like, aromatic stmcture of 1,2,3-benzothiadiazole imparts stability to the system that survives exposure to 20% potassium hydroxide at 150°C or 27% sulfuric acid at 200 °C. It is not oxidized by potassium permanganate, potassium ferricyanide, chromic acid, or dilute nitric acid <1996CHEC-II(4)289>. Electrophilic substitution occurs in the benzo ring, predominantly at the 4-position. Chlorine in the 6-position is displaced by a variety of nucleophiles <1975SST670>. 

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