Phenol Oxidation Reaction Research Articles

Purification and characterization of dihydrogeodin oxidase from a fungal strain of Aspergillus terreus producing (+)-geodin.

Dihydrogeodin oxidase (DHGO), an enzyme catalyzing regio- and stereo-specific intramolecular phenol oxidative coupling reaction of dihydrogeodin to give (+)-geodin, was purified up to homogeneity. DHGO was shown to be a blue copper protein with an absorption maximum at 600 nm. The presence of copper atoms was confirmed by atomic absorption analysis. A molecular weight of 153, 000 was estimated for the oxidase and it was composed of two equal molecular weight subunits. DHGO had no phenolase activity and showed strict substrate specificity.

Cooxidation of Carcinogenic Benzo(a) Pyrene and Phenols by Horseradish Peroxidase (Armoracia lapathifolia)

AbstractThe catalytic activity of horseradish (Armoracia lapathifolia) peroxidase in the oxidation reactions of benzo(a)pyrene (BP) and phenols, separately and in admixture, has been studied. Experiments were carried out with model phenols from industrial sewage (phenol, m‐, p‐cresols, catechol, hydroquinone, resorcinol, orcinol), keeping to the real concentration ratio of reagents, 0.5 mM for phenols, 0.1 nM for benzo(a)pyrene.The total oxidation process for all reagents tested is described by the second‐order formal kinetic equation up to 60 … 90% of their conversion. Addition of peroxidase increases the rate of oxidation of benzo(a)pyrene and phenols 2 … 6 times as compared with the control test (with hydrogen peroxide), whereas a linear dependence of the rate of benzo(a)pyrene oxidation on the enzyme concentration is observed.By cooxidation a mutual inhibition of benzo(a)pyrene and phenols is established whose degree depends on the phenol‐chemical structure and varies in the range of 23 … 58% for BP under the influence of phenols and 35 … 80% for phenols under the influence of benzo(a)pyrene.The results obtained permit a supposition that peroxidase containing plants are capable of simultaneously transforming carcinogenic benzo(a)pyrene and toxic phenols in water reservoirs and in the soil, thus promoting the detoxication of environment.

Quinones and quinone-methides—I : Cyclization and dimerisation of crystalline ortho-quinone methides from phenol oxidation reactions

Silver oxide or 2,3-dichloro-5,6-dicyanobenzoquinone oxidation of 2-cinnamyl-4,5-methylenedioxyphenol yields a crystalline ortho-quinone methide, which undergoes thermal or acid-catalysed cyclization to 6,7-methylene-dioxyflav-3-ene. Oxidation of 2-(4-methoxybenzyl)-4,5-methylenedioxyphenol yields a crystalline ortho-quinone methide which rapidly dimerises in polar solvents. The structure of the colorless dimer, which is of a type not previously reported, suggests that an ionic reaction is involved in its formation.

Determination of Copper by Catalysis of the Oxidation Reaction of O-Amino Phenol

Abstract The oxidative dimerization reaction of o-amino phenol with dissolved oxygen is catalyzed by the presence of an extremely small amount of copper(II) ion. In a. c. polarography, the oxidation product of o-amino phenol gives a very sensitive tensammetric wave in the pH range 5 to 9. This tensammetric wave is used for the determination of copper(II) ion from 0.3 to 3.5 μg/100 ml final solution.

2-フェノキシメチルクロマノン類縁体の合成と反応 ロテノイドに関する研究(第2報)

Preparation of 2-phenoxymethylchromone (10 a, b), chromanol (11 a, b) and chromanone (12 a, b) and the attempt to convert to rotenoids were described. Condensation of ethyl phenoxyacetate (7 a, b) and acetophenone (8) afforded 2-phenoxymethylchromone (10 a, b). Bromination of the corresponding chromanone (5 a) gave a mixture of mono-bromides (12 a, b) and a dibromide (12 c). Reaction of 12 c with KNH2 afforded bromochromone (13). Treatment of chromanol (11 a) with PPA or H2SO4 and chromene (14) with HBr-AcOH gave the same bicyclo-3, 9-dioxa-(4, 3, 1)-decane derivative (17 a). Reaction of chromone alcohol (19) with PPA gave coumaranone derivative (20). Phenol oxidation reaction of dihydroxyphenoxymethylchromanone (5 b) afforded hydroxymethylchromanone (23 a).

Mechanism of phenolic oxidative coupling reactions. Ferricyanide oxidation of 2,3',4-trihydroxybenzophenone, an example of a radical aromatic substitution mechanism

Mechanism of phenolic oxidative coupling reactions. Ferricyanide oxidation of 2,3',4-trihydroxybenzophenone, an example of a radical aromatic substitution mechanism

Studies on the syntheses of heterocyclic compounds. Part CCCLXXXVI. Alternative total syntheses of galanthamine and N-benzylgalanthamine iodide

Alternative total syntheses of galanthamine (Ia) and N-benzylgalanthamine iodide (VIa) were carried out by phenolic oxidative reactions of the corresponding amides (IIIf and e). Both (–)-and (±)-galanthamine showed analgesic activity comparable to that of morphine.

Phenol Oxidation of Isoquinoline Alkaloids. II. Oxidative Coupling of dl-N-Methylisosalsoline

Oxidative coupling of dl-N-methylisosalsoline (III) with potassium ferricyanide was carried out, and the structures of the products were determined. It was found that III gives rise both to biphenyl derivatives (VI, VII) and diphenyl ether derivative (IV), and a steric participation of 1-substituent of 2-methyl-6-methoxy-7-hydroxy-1, 2, 3, 4-tetrahydroisoquinoline derivative in the product development in the phenol oxidation reactions was observed.

Phenol Oxidation Reactions

AbstractThe use of well‐known phenol oxidation reactions for the preparation of compounds arising from CC and CO coupling has recently received increased attention. A selection from the large number of products obtainable by oxidation of mono‐ and polyhydric phenols and a discussion of the reaction mechanisms indicate the scope of this method. The formation of hydroxyphenylquinones and orceine dyes from resorcinol derivatives is explained. The synthesis of natural products by way of phenol oxidations is briefly discussed.