Arenes biological oxidation

Anti-Markovnikov addition, 220 D-Apiose, 988, 1011 Aprotic solvents, 322, 875 D-Arabinitol, 1009 D-Arabinose, 977, 1006, 1009 L-Arabinose, 976, 1001 Arachidic acid, 1018, 1025 Arachidonic acid, 1018, 1025 Aramid polymers, 809 Archaea, 58, 299 Arene oxides, 409, 948, 1064 Arenes, 54, 398-442 biological oxidation, 409, 417, 948, 1064 infrared spectra, 519 table nuclear magnetic resonance spectra carbon, 513 table proton, 495-496 Arenium ion, 444 L-Arginine, 1055, 1059... 

The current views about aerobic biological oxidation of alkanes and arenes involving various oxygenases. Its chemical simulations are discussed in this chapter, which gives only a brief survey of the most recent data for biological C-H activation and hydrocarbon oxidation. It is noteworthy that, somewhat unexpectedly, important and profound analogies exist between chemical activation by metal complexes and biological C-H oxidation. It is necessary to note that many books [14] and reviews [15] have been devoted to enzymatic oxidations and processes that more or less closely model these oxidations. 

One ammo acid often serves as the biological precursor to another L Phenylala nine is classified as an essential ammo acid whereas its p hydroxy derivative L tyro sine IS not This is because animals can convert L phenylalanine to L tyrosine by hydrox ylation of the aromatic ring An arene oxide (Section 24 7) is an intermediate... 

Any biologically produced molecular entity or species having substituents derived from different origins or pathways. For example, glutathione reacts with many arene oxides, and the bioconjugate product is then processed for excretion. Bioconjugates are often more water-soluble, and they are typically more readily com-partmentahzed and/or metabohzed. 

Cerniglia, C. E., Althaus, J. R., Evans, F. E., Freeman, J. P., Mitchum, R. K. Yang, S. K. (1983). Stereochemistry and evidence for an arene-oxide-NIH shift pathway in the fungal metabolism of naphthalene. Chemico-Biological Interactions, 44, 119-32. 

The main focus of interest in arene oxides, however, has been their formation and role under biological conditions. There are a number of reviews.1-8 Every attempt has been made in this article to cover the literature... 

Because of the great biological significance of arene oxides and the large number of different reactions they could undergo in water and with animal tissues, detailed quantitative studies have been carried out with a variety of arene oxides in aqueous medium. (See Table VI). 

One of the main points of interest in arene oxides arises from their biological reactions. At one time it was believed that arene oxides were the proximate intermediates responsible for carcinogenesis, mutagenesis, and necrosis. It will be useful to trace briefly the development of the current ideas of the involvement of arene oxides in carcinogenesis. 

The least reactive (354) is mutagenic and the most reactive (253) is not mutagenic. This indicates that the chemical reactivity (both SN1 and SN2 reactions) forming a covalent carbon-nitrogen bond is not the only factor that determines the biological activity of arene oxides, though a certain minimum reactivity may be required. 

M. M. Marsh and D. M. Jerina, J. Med. Chem., 21 1298 (1978). Calculated Properties of Arene Oxides of Biological Interest. I. Molecular Orbital Examination of Simple Models. 

The catalytic oxidations of alkanes, alkenes, and other substances are of enormous technological and biological importance. In addition to classical oxidations of unsaturated substances like alkenes and arenes there is an increasing number of systems capable of catalyzing the selective oxidation of saturated hydrocarbons. 

The Udenfiiend system of 1954 was perhaps the first to be specifically presented as a model of a biological process. In this system, Fe(II) is the catalyst, EDTA the ligand, air is the primary oxidant and ascorbic acid provides the reducing equivalents called for in this monooxygenase system. Arenes can be hydroxylated to phenols, alkanes to alcohols, and alkenes to epoxides, although with modest efficiency. The NIH shift was not observed in the model, however. 

The principal pathway by which unsubstituted and many substituted aromatic hydrocarbons are metabolized in mammals consists of the initial formation of arene oxides, which undergo a variety of enzymatic and nonenzymatic reactions prior to excretion of the resulting more polar, oxidized hydrocarbons via bile or urine. Taken together, these pathways represent an attempt on the part of the animal to detoxify or eliminate such nonpolar xenobiotic substances for which it has no apparent use. Although detoxification is the probable role of the arene oxide pathway, it is equally clear that chemically reactive species mediate this process. Thus, studies over the past several years have either implicated or established arene oxides in a causative role in such adverse biological reactions as cytotoxicity, mutagenesis, and carcinogenesis via covalent interaction of arene oxides with biopolymers,... 

The metabolic oxidation of otefinic carbon-carbon double bonds leads to the corresponding epoxide (or oxiranc). Epoxides derived from olefins generally tend to be somewhat more stable than the arene oxides formed from aromatic-compounds. A few epoxides arc stable enough to be direclly mcasurable in biological fluids (e.g.. plasma, urine). Like their arene oxide counterparts, epoxides- are susceptible to cnz.ymatic hydration by epoxide hydra.se to form lran,s-. 2-dihydrodiols (al.so called 1,2-diols or 1.2-dihydroxy com-... 

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