Triphenylene oxide

Mefiiyl mefiiacrylate-co-4-vinylpyridine Triphenylene oxide Single Tg FTIR I had 11 mol% vinylpyridine II was sulfonated or phenylated Rajagf alan et al. (2003)... 

Relative modulus versus talc clay-reinforced agent content for nanocomposites based on a thermoplastic polyolefin or a triphenylene oxide matrix polypropylene plus ethylene-based elastomer showed that relative to a particular filler content, an appreciably higher modulus content was obtained for the montmorillonite reinforcing agent than for talc [156]. Doubling the modulus of the phenylene oxide requires about four times more talc than montmorillonite, with the talc-reinforced polymer having an improved surface finish. In the case of the talc-reinforced polymer, exfoliation is appreciably better than with clay reinforcement. The talc-reinforced polymer has automotive applications. 

Triphenylene has been prepared by self-condensation of cyclohexanone using sulfuric acid or polyphosphoric acid followed by dehydrogenation of the product, palladium-charcoal, or selenium by electrolytic oxidation of cycloliexanone from chlorobenzene and sodium or phenyllilhium from 2-cyclolu xyl-l-phenylcyelohexanol or... 

Photoisomerization of benz[a]anthracene 3,4-oxide, triphenylene 1,2-oxide, and benz[a]an-thracene 1,2-oxide yields anthra[2,l-6]oxepin [mp 125-126 C (pentane/Et20)], phen-anthro[10,9-/r]oxepin [mp 109-110°C (hexane/Et20)], and anthra[2,1 -/joxepin [mp 70CC (dec., pentane/Et20)], respectively.12 0... 

Methods for the synthesis of the biologically active dihydrodiol and diol epoxide metabolites of both carcinogenic and noncarcinogenic polycyclic aromatic hydrocarbons are reviewed. Four general synthetic routes to the trans-dihydrodiol precursors of the bay region anti and syn diol epoxide derivatives have been developed. Syntheses of the oxidized metabolites of the following hydrocarbons via these methods are described benzo(a)pyrene, benz(a)anthracene, benzo-(e)pyrene, dibenz(a,h)anthracene, triphenylene, phen-anthrene, anthracene, chrysene, benzo(c)phenanthrene, dibenzo(a,i)pyrene, dibenzo(a,h)pyrene, 7-methyl-benz(a)anthracene, 7,12-dimethylbenz(a)anthracene, 3-methylcholanthrene, 5-methylchrysene, fluoranthene, benzo(b)fluoranthene, benzo(j)fluoranthene, benzo(k)-fluoranthene, and dibenzo(a,e)fluoranthene. 

The trimethylsilyloxy (TMSO) group is stable under the coupling conditions in acetonitrile (Table 12, number 6). After oxidative dimerization the TMS-ether can be mildly hydrolyzed (H+ and H2O) to the phenol or converted to a dibenzofuran. 1,2-Dialkoxybenzenes have been trimerized to triphenylenes (Table 5, numbers 7, 8). The reaction product is the triphenylene radical cation, which is reduced to the final product either by zinc powder or in a flow cell consisting of a porous anode and cathode [188]. Anodic trimerization of catechol ketals yields triphenylene ketals, which can function as a platform for receptors, for example, in an artificial caffeine receptor [190]. 

It was Breslow (Breslow, 1982 Breslow et ai., 1982) who first paid attention to this theory. Knowing that the pentachlorocyclopentadienyl cation (Breslow et ai, 1964 Saunders et ai, 1973), the hexachlorobenzene dication (Wasserman et al., 1974) and the 2,3,6,7,10,11-hexamethoxy-triphenylene (HMT, [36]) dication are all ground-state triplets, in good agreement with theory, Breslow and coworkers set out on the synthesis of analogues that should have lower oxidation potentials, be chemically more stable and therefore form CT complexes more readily (Fig. 21c Breslow et al., 1982, 1984 Breslow, 1985, 1989 LePage and Breslow, 1987). 

The photolysis of 4-nitroanisole in degassed acetonitrile or benzene yields 4-nitro-soanisole and 2-nitro-4-methoxyphenol is). Triphenylene (Et = 67 kcal mole i 4-nitroanisole t=59.5 kcal mole i has been used to sensitize the reaction, which is suppressed completely by nitric oxide. A rationale for the formation of the products observed is given below. 

A second example from the same group is the synthesis of an elaborate diethynyltriphenylene derivative (Scheme 7 Table 8,entries 12,13) [58].Zn/Pd-promoted homocoupling of a 4-iodo-l,2-dialkoxybenzene furnishes the desired tetraalkoxybiphenyl, an electron-rich aromatic system. Iron trichloride-catalyzed Friedel-Crafts arylation of the biphenyl derivative with dimethoxy-benzene furnishes an unsymmetrical triphenylene derivative. Deprotection, oxidation, and subsequent Diels-Alder reaction with cyclohexadiene is followed by catalytic hydrogenation and reoxidation. TMS-CC-Li attack on the quinone delivers the alkyne modules, treatment with SnCl2 aromatizes the six-mem-bered ring, while KOH in MeOH removes the TMS groups cleanly to give the elaborate monomer. 

Treatment of veratrole (191) with excess of 2,5-dichloro- (192) or 2,6-dichloro-1,4-benzoquinone in 70% sulfuric acid yields dibenzofurans and other products. Thus 2,5-dichloro-1,4-benzoquinone (192, Scheme 49) affords the dibenzofuran 193, the diarylquinone 194 and the triphenylene 195. The quinol formed by acid-catalyzed addition of veratrole (191) to the quinone 192 is presumably oxidized to the arylquinone 196, which can form the dibenzofuran 193 or undergo further arylation. The quinone 196 is also available by arylation of 2,5-dichloro-1,4-benzoquinone (192) with 3,4-di-methoxybenzenediazonium chloride in buffered solution. On treatment with 70% sulfuric acid, the arylquinone 196 affords the dibenzofuran 193 (88%). The cyclization can also be effected photochemically. The aryl-quinones available by treatment of 2,5- and 2,6-dichloro-1,4-benzoquinones with buffered solutions of diazotized 4-methoxy-3-methyl- and 3-methoxy-4-methylaniline have been cyclized to 2-dibenzofuranols by the agency of aluminum chloride in hot benzene. ... 

Polynuclear aromatics that cannot form K-region epoxides such as anthracene may be oxidized to the corresponding quinones806 by these reagents. Others, such as naphthalene and triphenylene, may be converted to polyepoxides under carefully controlled reaction conditions and workup procedures.808,809... 

The novel arenium ion 95 was synthesized266 by one-electron oxidation of the triphenylene-based starting compound to form a radical cation which abstracted a chlorine atom with a concomitant rearrangement to yield the hexachloroantimonate salt. The arenium ion character is apparent from the 13C spectrum (three signals at 813C 212.9, 187.6, and 173.6) and from the bond distances, which are very close to those shown for ion 91. Cation 95 can be stored at room temperature for months. This exceptional stability was attributed to the annelation to the two bicyclo[2.2.2]octane units and the spiroconjugation effect of the fluorenyl moiety.267... 

Bushby has examined the FeCl3-mediated oxidation of hexyl-protected (Hex) phenol ether units in the preparation of triphenylene-based liquid crystals [63]. This strategy allows the formation of unsymmetrically substituted products 75a-l (Table 18) [64]. The use of methanol in the work-up is critical in order to obtain the products in good yield. If the protecting group on the phenol component is isopropyl (74m), the coupling reaction occurs to give the unprotected phenols 76a-c directly (Scheme 17) [65]. 

Tab. 18. Synthesis of triphenylenes 75 by oxidative coupling of biphenyl and phenyl ether components.

Scheme 22. Triphenylene synthesis by VOC -mediated oxidative coupling of catechol ethers with biphenyls.

Scheme 23. Triphenylene synthesis by VOCl3-mediated oxidative coupling of trialkoxybenzenes with biphenyls.

Crown ether-functionalized polyphenylenes are a class of electroactive polymers obtained by electropolymerization (anodic coupling) of (di)benzo- or (bi)naphthalene-crown ethers <1998CCR1211, 1998PAC1253>. Tricyclic triphenyl-ene derivatives, such as 78, can be electrogenerated from benzo-15-crown-5 <1989NJC131> and benzo-18-crown-6 <1992JEC399>. Similarly, the anodic oxidation of dibenzo-crown ethers has produced poly(dibenzo-crown ethers), best represented by 79, where triphenylene moieties are presumably two-dimensionally linked via polyether bridges. 

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>. 

Fukui et al. s (8) ideas were refined to extend their validity to other types of reactions, but here I need only mention an interesting remark in the original paper. The authors observed that triphenylene is more stable to oxidation than naphthacene and phenantrene more than anthracene they concluded that, at a constant number of carbons and tt electrons, those... 

Oxidation of arenes under nonaqueous conditions often results in polymerization [93], which has been observed for most of the simple arenes, such as benzene [94-97], naphthalene [98], pyrene [99], biphenyl [96], triphenylene [99], fluoranthene [99], and fluor-ene [99-101]. (See Chapter 32 for details.) Polymerization is often accompanied by severe electrode passivation [100]. 

Triphenylenes provided with nonionic di(ethylene oxide) side-chains (25f)132 134 or with ionic alkyl chains (25g)135 form supramolecular polymers in water.136 The arene—arene interactions of the aromatic cores allow for the formation of columnar micelles . At low concentrations the columns are relatively short, and the solutions are isotropic. At higher concentrations the longer columns interact and lyotropic mesophases are formed.133 Computer simulations showed that in the isotropic solution the polymerization of the discotics is driven by solute-solute attraction and follows the theory of isodesmic linear aggregation the association constants for dimerization, trimerization, and etc., are equal and the DP of the column thus can easily be tuned by concentration and temperature.137 138 At higher concentrations the sizes of the columns are influenced by their neighbors, the columns align, and the DP rises rapidly. 

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