Phenols catechols

Tao Y, A Fishman, WE Bentley, TK Wood (2004) Oxidation of benzene to phenol, catechol, and 1,2,3-trihydroxybenzene by toluene 4-monooxygenase of Pseudomonas mendocina KR 1 and toluene... 

The partial dechlorination of chlorinated anilines has been examined in anaerobic slurries, which has already been noted (Kuhn et al. 1990), while D. hafniense (frappieri) strain PCP-1 is able to dechlorinate a wide range of polychlorinated aromatic substrates including phenols, catechols, anilines, pentachloronitrobenzene, and pentachloropyridine (Dennie et al. 1998). Both pentachloro-aniline and 2,3,5,6-tetrachloroaniline were partially dechlorinated to dichloroanilines, although the orientation of the substituents was unresoved. The kinetics of dechlorination of pentachloroaniline have been described (Tas et al. 2006). 

Description of the model. Benzene and its metabolites (phenol, catechol, and hydroquinone) were assumed to compete for the same reaction site on the enzyme cytochrome P-450 2E1. In addition, phenol can undergo both oxidation and conjugation, although the enzymes for each of these reactions are localized in different compartments of the liver, and competition between them is thereby regulated. 

This model incorporates observations made in an earlier kinetic study that investigated benzene and phenol metabolism in vitro in mouse and rat liver microsomes (Schlosser et al. 1993). In that study, the following reaction sequences were postulated benzene phenol catechol trihydroxybenzene and phenol hydroquinone trihydroxybenzene. 

Grodnick JS, Dupre GD, Gulizia BJ, et al. 1983. Determination of benzene, phenol, catechol and hydroquinone in whole blood of rats and mice. J Chromatog Sci 21 289-292. 

Hattula, M.L., Wasenius, V.-M., Reunanen. H., and Arstila, A.U. Acute toxicity of some chlorinated phenols, catechols and cresols in trout, Bull. Environ. Contam. Toxicol, 26(3) 295-298, 1981. 

E. Kimura, Pure Appl. Chem. 58, 1461 (1986) Macrocyclic Polyamines with Pendent Phenol, Catechol, Hydroquinone, and Pyridine Group". 

The pH values of efficient extraction correspond to the pH range where the molecular form of the respective phenol dominates. The recovery of 4-nitro-phenol, 2,4-dinitrophenol, 2,6-dinitrophenol, 4-chlorophenol, 1-naphthol, and 2-naphthol is above 90% (the ratio of aqueous organic phase volume is 3 1). The extraction of naphthol and 4-chlorophenol is significant even at pH > pffa, more than 40 and 24% at pH > 10, respectively. Recovery of picric acid (2,4,6-trinitrophenol) is about 90% at pH 1.5-12.0, where the anionic form of picric acid dominates. Obviously, the high extraction is caused by high hydrophobicity of picrate anions. Recovery of the phenol itself and diatomic phenols, catechol and resorcinol is rather moderate (79,58, and 20%, respectively pH 1-7), which could be explained by relatively high hydrophi-licity of these compounds. 

Catechol may be oxidized by peroxidases to the reactive intennediate benzo-1,2-quinone, which readily binds to proteins (Bhat et al., 1988) this process, catalysed by rat or human bone-marrow cells in the presence of H2O2 (0.1 mM), is stimulated by phenol (0.1-10 mM), and decreased by hydroquinone and by glutathione, which conjugates with benzo-l,2-quinone. These phenols (phenol, catechol and hydroquinone) may play a role in benzene toxicity to bone marrow all three are formed as benzene metabolites (Smith et al., 1989) and they interact in several ways as far as their bioactivation by (myelo)peroxidases is concerned (Smith et al., 1989 Subrahmanyam et al., 1990). 

Rasanen, L., Hattula, M.L. Arstila, A.U. (1977) The mutagenicity of MCPA and its soil metabolites, chlorinated phenols, catechols and some widely used slimicides in Finland. Bull, environ Contam. Toxicol., 18, 565-571... 

Hypertensin is soluble in alcohol, glacial acetic acid, phenol, and water, and insoluble in ether (61). Because it is inactivated by tyrosinase it probably contains a catechol or phenol group, and by amine oxidase, an amine group on an a-carbon atom (Figure 2). Hypertensin is inactivated by certain phenolic, catecholic, and amine oxidases, by pepsin, trypsin, chymotrypsin, and carboxypeptidase, and by hypertensinase found in plasma. The nature of hypertensinase is unknown, but it is probably not an oxidative enzyme. Because it is heat-labile, hypertensinase can be removed from blood and renin preparations by heating hypertensin itself is heat-stable. Lack of pure preparations of hypertensin has delayed its further chemical identification. 

Naphthoquinone/perchloric acid Yellow spots (phenol, catechol) dark blue spots (resorcinol) 65... 

Triazaphosphaadamantane forms complexes with phenol, catechol, resorcinol, and hydroquinone. These compounds are similar to those formed by hexamethylenetetramine, and were proposed as intermediates for the preparation of Bakelite-type resins (76MI1). 

Ferapontova EE, Castello J, Gorton L (2006) Bioelectrocatalytic properties of lignin peroxidase from Phanerochaete chrysosporium in reactions with phenols, catechols and lignin-model compounds. Biochim Biophys Acta 1760 1343-1354... 

The hydrogenation of phenols may proceed more readily than other aromatic compounds under proper use of catalyst and conditions. Over Ni-kieselguhr, hydroxyben-zenes such as phenol, catechol, and resorcinol are hydrogenated rapidly at 120-150°C under high pressure. Usually, the yields of the corresponding cyclohexanols are quantitative except for resorcinol, which gave only a 90% yield of cyclohexane-1,3-diol.70 An example is shown in eq. 11.11 for the hydrogenation of phenol. 

Benzene was also distributed to the kidney, lung, liver, brain, and spleen. The benzene metabolites phenol, catechol, and hydroquinone were detected in blood and bone marrow following 6 hours of exposure to benzene, with levels in bone marrow exceeding the respective levels in blood. The levels of phenol in blood and bone marrow decreased much more rapidly after exposure ceased than did those of catechol or hydroquinone, suggesting the possibility of accumulation of the latter two compounds. 

There are quantitative differences in the benzene metabolites produced by different species (Sabourin et al. 1988). Fischer 344 rats exposed to 50 ppm benzene had undetectable amounts of phenol, catechol, and hydroquinone in the liver, lungs, and blood. The major water-soluble metabolites were muconic acid, phenyl sulfate, prephenyl mercapturic acid, and an unknown The unknown was present in amounts equal to the amounts of phenyl sulfate in the liver phenyl sulfate and the unknown were the major metabolites in the liver. B6C3Fj mice exposed to 50 ppm benzene had detectable levels of phenol and hydroquinone in the liver, lungs, and blood catechol was detectable only in the liver and not in the lungs or blood. As in the rat, the unknown was present in amounts equal to the amounts of phenyl sulfate in the liver. Mice had... 

Complexes of Phenols, Catechols, Quinones and Related Systems 230... 

Aryl sulfotransferases catalyze the transfer of the sulfuryl moiety from 3 -phosphoadenosine 5 -phosphosulfate to phenols, catechols, benzylic alcohols, arylhydroxylamines, and arylhydroxamic acids. This assay measures adenosine 3, 5 -diphosphate and is thus suited to quantitate enzyme activity when the sulfate esters formed are chemically unstable. 

Mostafa et al. [416] noted that the uptake of substituted phenols did not follow Traube s rule but instead did decrease in the order of their increasing pK values o-chlorophenol > hydroquinone > resorcinol > phenol > catechol > pyrogallol. Even though the experiments were performed at (unspecified) pH where the adsorbates were predominantly in an undissociated form, the authors noted that the acidity of the adsorbate is an important factor in determining its adsorption capacity this was not surprising to them because, presumably, the ability [of steam-activated and thus alkaline carbons] to remove phenols is expected to... 

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