Oxidative Stress, Inflammation, and Cancer: How Are They Linked?

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Aryl-aryl bond formation one century after the discovery of the Ullmann reaction.

The biaryl structural motif is a predominant feature in many pharmaceutically relevant and biologically active compounds. As a result, for over a century 1 organic chemists have sought to develop new and more efficient aryl -aryl bond-forming methods. Although there exist a variety of routes for the construction of aryl -aryl bonds, arguably the most common method is through the use of transition-metalmediated reactions. 2-4 While earlier reports focused on the use of stoichiometric quantities of a transition metal to carry out the desired transformation, modern methods of transitionmetal-catalyzed aryl -aryl coupling have focused on the development of high-yielding reactions achieved with excellent selectivity and high functional group tolerance under mild reaction conditions. Typically, these reactions involve either the coupling of an aryl halide or pseudohalide with an organometallic reagent (Scheme 1), or the homocoupling of two aryl halides or two organometallic reagents. Although a number of improvements have developed the former process into an industrially very useful and attractive method for the construction of aryl -aryl bonds, the need still exists for more efficient routes whereby the same outcome is accomplished, but with reduced waste and in fewer steps. In particular, the obligation to use coupling partners that are both activated is wasteful since it necessitates the installation and then subsequent disposal of stoichiometric activating agents. Furthermore, preparation of preactivated aryl substrates often requires several steps, which in itself can be a time-consuming and economically inefficient process.

http://aether.cmi.ua.ac.be/artikels/Artikels%20Gitte/Artikels/Reviews/Heck-Type-lautens.pdf

Aryl-aryl bond formation by transition-metal-catalyzed direct arylation.

Graphenes as potential material for electronics.

Reduced graphene oxides (RG-Os) have attracted considerable interest, given their potential applications in electronic and optoelectronic devices and circuits. However, very little is known regarding the chemically induced reduction method of graphene oxide (G-O) in both solution and gas phases, with the exception of the hydrazine-reducing agent, even though it is essential to use the vapour phase for the patterning of hydrophilic G-Os on prepatterned substrates and in situ reduction to hydrophobic RG-Os. In this paper, we report a novel reducing agent system (hydriodic acid with acetic acid (HI-AcOH)) that allows for an efficient, one-pot reduction of a solution-phased RG-O powder and vapour-phased RG-O (VRG-O) paper and thin film. The reducing agent system provided highly qualified RG-Os by mass production, resulting in highly conducting RG-O(HI-AcOH). Moreover, VRG-O(HI-AcOH) paper and thin films were prepared at low temperatures (40 °C) and were found to be applicable to flexible devices. This one-pot method is expected to advance research on highly conducting graphene platelets.

/pdf/reduced-graphene-oxide-by-chemical-graphitization-nhqs5c2ati.pdf

Reduced graphene oxide by chemical graphitization

Evidence has been obtained that a specific isomer of a diol epoxide derivative of benzo(a)pyrene, (+/-)-7 beta,8alpha-dihydroxy-9alpha, 10alpha-epoxy-7,8,9,10-tetrahydrobenzo(a)pyrene, is an intermediate in the binding of benzo(a)pyrene to RNA in cultured bovine bronchial mucosa. An adduct is formed between position 10 of this derivative and the 2-amino group of guanine.

https://science.sciencemag.org/content/sci/193/4253/592.full.pdf

Benzo(a)pyrene diol epoxides as intermediates in nucleic acid binding in vitro and in vivo.

PUBLICATION by Sims et al. of evidence that the 7,8-dihydrodiol-9,10-oxide of benzo(a)pyrene (BP) is a metabolic intermediate in the covalent binding of this ubiquitous polycyclic aromatic hydrocarbon to DNA in hamster embryo cells1 was followed by many related publications2. Grover et al.3 also obtained evidence that the same derivative is involved in the binding of BP to the DNA of human bronchial explants, although details of the specific isomer involved and of the structure of the adduct were not reported. We describe here studies on RNA and DNA adducts formed by human bronchial explants and provide evidence that the structures of the major adducts are similar to those formed in the analogous bovine system.

Structures of benzo(a)pyrene–nucleic acid adducts formed in human and bovine bronchial explants

Dehydrogenation of polycyclic hydroaromatic compounds

Benzo[a]pyrene-nucleic acid derivative found in vivo: structure of a benzo[a]pyrenetetrahydrodiol epoxide-guanosine adduct

http://www.jbc.org/content/277/27/24799.full.pdf

Activation of polycyclic aromatic hydrocarbon trans-dihydrodiol proximate carcinogens by human aldo-keto reductase (AKR1C) enzymes and their functional overexpression in human lung carcinoma (A549) cells.

Ronald G. Harvey

Papers

Benzo(a)pyrene diol epoxides as intermediates in nucleic acid binding in vitro and in vivo.

Structures of benzo(a)pyrene–nucleic acid adducts formed in human and bovine bronchial explants

Dehydrogenation of polycyclic hydroaromatic compounds

Benzo[a]pyrene-nucleic acid derivative found in vivo: structure of a benzo[a]pyrenetetrahydrodiol epoxide-guanosine adduct

Activation of polycyclic aromatic hydrocarbon trans-dihydrodiol proximate carcinogens by human aldo-keto reductase (AKR1C) enzymes and their functional overexpression in human lung carcinoma (A549) cells.