Naphthalenes, from indenes

Scheme 6.55 One-pot procedure, starting from indene, for the preparation of the cycloadducts of 3<52-l H-naphthalene (221) to 1,3-cyclopentadiene.

The dehydrocyclization of alkylaromatics was first described more than four decades ago. In 1936 Moldavskii and Kamusher reported the formation of naphthalene from u-butylbenzene on chromia at 475°C (7, 2). In 1945 Herington and Rideal reported the formation of indene from w-propyl-benzene over chromia-alumina (3). Platinum-containing catalysts were first used for these reactions in 1956 by Kazanskii and co-workers 4-6). 

Carbon black may serve as a low-cost additive for controlling the gas migration in cement slurries [303]. It is intended as a suitable substitute for polymer latex and silica fume and has been tested in field applications [304,1256]. The concentration of carbon black varies from 2 to 20 parts, based on the weight of the dry cement [1220]. The particle size varies from 10 to 200 nm. A surfactant is necessary for dispersion, for example, formaldehyde-condensed naphthalene sulfonate or sulfonated cumarone or indene resins. 

In a somewhat different approach, Asahi Glass KK have claimed [132] that the addition of a transition metal salt (e. g., cobalt-, copper-, lead-, cerium-, bismuth-, manganese-, chromium-, iron- chloride, or cobalt fluoride, etc.) greatly improves the ECF production of perfluorobicyclic compounds, derived from naphthalene, indene, benzofuran, phthalimide, indole, quinolizine, benzotriazole, and quinoline. 

Cyclization to five-membered rings forms the alkylindans and indenes cyclization to six-membered rings gives tetralins and naphthalenes. Tetralins and decalins, however, were not observed in any of the experiments, because of unfavorable equilibrium. For example, less than 0.02-0.1% tetralin and less than 0.001% decalins would be expected if they were in equilibrium with the naphthalene formed in the n-butylbenzene experiments. [Equilibrium conversions calculated from the data of Egan (15), Allam and Vlugter (16), and Frye and Weitkamp (17)]... 

H 11.18% col pltlts(from benz or AcOH), giving a violet-red fluorescent color in soln, mp 25 0°, bp 448°, d 1.274 sol in hot benz or hot AcOH diffc sol in cold eth, CS2, AcOH or benz derived from coal-tar fractions boiling above 360° also produced by the cracking of petroleum fractions at 630-80° using catalysts, or by heating indene at 500-700° with catalysts, and by passing naphthalene coumarone thru a red-hot tube (Refs 1 to 4). Other props methods of prepn are given in the Refs... 

Adduct from naphthalene was also obtained by the reaction of octaflu-oronaphthalene (43) with indene [129] (Scheme 19). Photoirradiation of cyclo-... 

Many reactions afford, in addition to the naphthalene derivatives, mixtures of products. One of the major side reactions is the formation of indene derivatives directly from the metathesis intermediate without insertion of carbon monoxide. Other products frequently isolated as minor components are furans, cyclobutanones, and cyclopentenediones. The product distribution is dependent on numerous factors, including solvent, reaction temperature, concentration of the alkyne, and the nature of the aryl substituent. Molybdenum carbenes give, depending on the alkyne, either naphthols or indenes exclusively. The molybdenum Fischer carbenes can be tuned to give naphthoquinones by replacing one of the carbon monoxide ligands with a phosphine (Scheme 45). 

In the pyrolysis of polyethylene at 810°C, the low boiling fraction contains, apart from benzene, more than 10 wt-% of cyclo-pentadiene. If benzene-rich first runnings and last runnings (toluene-rich) are removed, one can obtain a fraction containing about 98 wt-% of benzene. The main constituents of the high boiling fractions are naphthalene, methylnaphthalene and indene, as well as highly condensed aromatics. 

For the addition of furan and benzofuran to benzocyclopropene, a diradical mechanism has been proposed for the formation of 4. Similarly, AT,At-dimethyl- or A-methyl-A-phenyl-hydrazones of a,/ -unsaturated aldehydes (acrylaldehyde and 2-methylacrylaldehyde) reacted by radical addition at the C-C double bond with benzocyclopropene at 45 C to yield a dihydro-indene derivative 5. The addition of tetracyanoethene to benzocyclopropene giving dihydro-indene 6a is, however, believed to be preceded by electron transfer from benzocyclopropene to tetracyanoethene.Cyclopropa[b]naphthalene reacted similarly with tetracyanoethene to give the dihydroindene derivative 6b in 44% yield. 

Similarly, alkane- and arenesulfonyl isocyanates gave 2-sulfonyl-2,3-dihydroisoindol-l-ones 11 with benzocyclopropene. 2,3-Dihydroisoindol-l-one was produced as a byproduct in 4% yield in the case of arenesulfonyl isocyanates. Cyclopropa[ ]naphthalene underwent addition to 4-phenyl-47/-l,2,4-triazole-3,5-dione at 20°C almost instantaneously to give an indazole 12 in 92% yield.Both reactions are believed to occur by electrophilic attack on the cyclo-proparene and may involve a zwittcrionic intermediate. When benzyne was generated from benzenediazonium-2-carboxylate in refluxing dioxane in the presence of cyclopropa[Z ]naph-thalenc, 5//-naphtho[2,5-a]indene was formed in 13% yield. 

Skeletal rearrangements of cycloalkanes containing 9-18 carbon atoms were observed for the first time by Prelog et al. (162) on Pd/C catalysts at 400°C. Under these conditions, polycyclic aromatic and pseudoaromatic hydrocarbons are obtained (indene, azulene, naphthalene, phenanthrene, etc.). By carrying out the reaction on Pt/C under less drastic conditions, Kazanskii et al. (163) could observe the precursors of the aromatics as primary products. The latter are bicycloalkanes resulting from transannular 1-5 or 1-6 dehydrocyclizations (Scheme 84). For instance, cyclooctane yields... 

It has been noted in Section 4.4.1.1 that naphthalene dioxygenase from a strain of Pseudomonas sp. also carries out enantiomeric monooxygenation of indan and dehydrogenation of indene (Gibson et al. 1995), and the stereospecific hydroxylation of (R)-l-indanol and (S)-l-indanol to rfs-indan-l,3-diol and trans (lS,3S)-indan-l,3-diol (Lee et al. 1997) the indantriols are also formed by further reactions. Essentially comparable reactions have been observed with Rhodococcus sp. strain NCIMB 12038 (Allen et al. 1997). 

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