Quinones, polycycle

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bond, such as o-naphthoquinone, since an analogous reaction of the latter provides a product of undetermined structure (unpublished result).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. 

While the reduction of polycyclic quinones to phenols, hydroquinones,... 

Enantiomers (M)- and (P)-helicenebisquinones [32] 93 have been synthesized by high pressure Diels-Alder reaction of homochiral (+)-(2-p-tolylsulfo-nyl)-l,4-benzoquinone (94) in excess with dienes 95 and 96 prepared from the common precursor 97 (Scheme 5.9). The approach is based on the tandem [4 + 2] cycloaddition/pyrolitic sulfoxide elimination as a general one-pot strategy to enantiomerically enriched polycyclic dihydroquinones. Whereas the formation of (M)-helicene is explained by the endo approach of the arylethene toward the less encumbered face of the quinone, the formation of its enantiomeric (P)-form can be the result of an unfavourable interaction between the OMe group of approaching arylethene and the sulfinyl oxygen of 94. 

Azulene quinones [49b] are compounds related to the family of tropones and are considered to possess great biological and physiological potential. Several polycyclic compounds have been prepared by high pressure (3kbar, PhCl, 130°C, 15h) Diels-Alder reaction of 3-bromo-l,5-azulene quinone (137) and 3-bromo-l,7-azulene quinone (138) with several dienophiles. The cycloadditions were regioselective and afforded cycloadducts in reasonable to good yields (Scheme 5.20). 

Hulbert, P. B. Grover, P. L. Chemical rearrangement of phenol-epoxide metabolites of polycyclic aromatic hydrocarbons to quinone-methides. Biochem. Biophys. Res. Commun. 1983, 117, 129-134. 

Although phenanthrene is noncarcinogenic, some of its methylated derivatives exhibit significant activity as mutagens (52,53). The 1,2- and 3,4-dihydrodiols of phenanthrene were first synthesized by Jerina et al. (54) by a method involving reduction of the corresponding quinones with LiAlH. However, the yields in the rein Polycyclic Hydrocarbons and Carcinogenesis Harvey, R. ... 

An alternative route to pyranthrone, involving baking 1,6-dibenzoylpyrene (6.96) with aluminium chloride, was also devised by Scholl (Scheme 6.18). The Scholl reaction is a key step in the synthesis of several polycyclic quinones the cyclisation of 1-benzoylnaphthalene to give benzanthrone (6.73) has already been mentioned. The mechanism of this cyclodehydrogenation reaction may involve an initial protonation step, if traces of water are present, or complexation with aluminium chloride. Electrophilic substitution is thereby... 

Isoviolanthrone (109) is an highly anellated polycyclic quinone system. It is derived from the chemical structure of isodibenzanthrone, which may be visualized as being obtained by unsymmetrical condensation of two benzanthrone molecules. The compound itself affords an intense blue shade. 

The brown algal order Fucales accounts for just over a third of known chemistry, with the genus Cystoseira accounting for more than 100 reported structures (Munro and Blunt 2005). The compounds are primarily prenylated quinones and hydroqui-nones, ranging from simple and linear to often complex and polycyclic forms as seen in cystoketal (sis to ke tal) (Fig. 1.61) (Amico et al. 1984) from C. balearica and from C. stricta (Fig. 1.6m)[B2] (Amico et al. 1987). 

Aliphatic amines are simple lone-pair n-donors, similarly to other n-donors like phosphines, ethers, alcohols, iodides etc. Aromatic amines may be both n- and rr-donors132. Typical rr-donors are polycyclic aromatic derivatives 7r-acceptors are polynitro aromatic derivatives, quinones etc. 

Anthralin (59), used clinically as an antipsoriatic, inhibited human ISN (7 /zM) the oxidation products of (59) (the corresponding quinone and dimer) were not active [164]. A non-specific antioxidant effect was suggested, since co-oxidation of LTB4 and mouse ear 12-LO were inhibited at similar concentrations [165]. However, some other phenolic polycyclic aromatic compounds appear more specific in their actions. 

In 1984, Giibble et al. reported for the first time a novel l,10-bis-(6-methyl-5H-benzo[fc]carbazol-ll-yl)decane (469) which has potential bifunctional nucleic acid intercalating properties (406). To function as anti-tumor active drugs, one of the most important cytostatic mechanisms of action of coplanar annelated polycyclic compounds is their intercalation with DNA (405). Ten years later, Kucklander et al. studied a series of 5H-benzo[ 7]carbazole quinone derivatives for their cytotoxic activity against colon and lung cancer cells, and found that the heteroannelated 5H-benzo[ 7]carbazole quinone derivative 470 was the most active among the various analogs (407) (Scheme 4.2). 

Porif.> (hydro)pyrimidine, macroQ clic and oligomeric pyridine or pyridinium, naphthyridine, oxazole, pteridine, pyridoacridine, pyrrole, pyrroloimiiMquinone, (oxa)quinoli2idine, terpenoid indolizidine. ISOPR. Monotero. rare Sesouitem. . Ditero.. Sestertero. also degraded C>i Tritero.. POLYKET. macrolides, polyacetylenes, polycyclic (hydro)quinones, polyethers, (epidioxy)polyp ionates. ... 

Orphan skeletons are emphasized in boldfece characters. Found both in the Tertiary and the Triassic eras, they have no equivalent in extant organisms and cannot be accounted for by di enetic transformations alone. They comprise xanthenoxanthene quinones, quincyte pigments of likely polyketide origin (Prowse 1991), and three series of isoprenoids polycyclic hydrocarbons from the... 

Pierce, R., and M. Katz, Chromatographic Isolation and Spectral Analysis of Polycyclic Quinones. Application to Air Pollution Analysis, Environ. Sci. Technol., 10, 45-51 (1976). 

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