Fused ring aromatic compounds

Kosan Biosciences was formed almost 6 years ago, founded on an interest in polyketides, microbial metabolite-based drugs. Polyketides have many diverse chemical structures including erythromycin, which will be mentioned again later. These chemicals include fused-ring aromatic compounds, compounds decorated with sugars, and compounds with large stretches of double bonds. Each of these compounds has different biological activities and utilities, but they are all made in nature by very similar biochemistry. 

With regard to possible relations between homogeneous hydrogenation systems and heterogeneous HDS catalysts, polynuclear aromatic molecules are easier to reduce by metal complexes than isolated benzene rings, since the partial saturation of fused-ring aromatic compounds does not suffer from as dramatic a loss of resonance stabilization ... 

Benzopyrene, C20H12, is a fused ring aromatic compound. Write its structural formula. 

The fused 3+ ring aromatics in petroleum include both cata- and peri-condensed stmctures (see Table 4, Fig. 8). The cata-condensed species are those stmctures where only one face is shared between rings, the peri-condensed molecules are those that share more than one face. The fused ring aromatics form the class of compounds known as polynuclear aromatic hydrocarbons (PAH) which includes a number of recognized carcinogens in the 4+ ring family (33). Because of the potential health and environmental impact of PAH, these compounds have been studied extensively in petroleum. 

The use of the stannylquinones 81 results in the regioselective formation of 1,4-naphthoquinones or 9,10-anthraquinones 82 [40]. Highly-oxygenated angularly-fused polycyclic aromatic compounds are prepared by the ring enlargement [41]. (Scheme 29)... 

For the above reaction to occur, the aromatic nuclei in compound 1 should carry activating groups, such as hydroxyl, alkoxy, or fused ring aromatics". As a result of reaction with BF3 and phenol, the macromolecular structure of coal should undergo rupture at the aliphatic bridges, and these bridges are transferred to phenol molecules to produce bisphenols. Analysis of the bisphenols should provide information on the aliphatic bridges present in coal structure. 

Similar to the benzynezirconocene, cyclohexyne, cyclopen-tyne, alkyne, alkene, cycloaUcene zirconocenes, and related species insert various substrates such as alkynes, alkenes, aldehydes, ketones, nitriles or phosphaalkynes. They lead in general five-membered zirconacycles, which can be converted by transmetalation or exchange reactions into fused-ring aromatic or heterocyclic compounds. The extension of this chemistry to heterobenzyne complexes can be realized, for instance, in phosphinine compounds. Consequently, under mild conditions, ) -phosphabenzyne-zirconocene complexes are formed and can be isolated either as PMes adducts or as dimers when the elimination reaction is carried out without added phosphane (Scheme 28). 

Multiple ring aromatic compounds are commonly referred to as polynuclear aromatic hydrocarbons or PAHs. The most common PAH is naphthalene. Naphthalene is a two-ringed unit. Three, four or more fused ring compounds also exist. 

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