Oxidative Coupling Of Phenols Research Articles

Design of the substrate for oxidative phenol coupling. An efficient synthesis of the C-homoerythrinan skeleton

Attention is drawn to the importance of conformational interactions in the cyclisation step of intramolecular phenolic coupling reactions. Careful design of the substrate molecule to minimise these interactions should result in better yields for this important strategy of natural product synthesis. The hypothesis is supported by the contrast in the behaviour of the 1-phenethylquinoline (5) and the 1-phenylacetamidoquinoline (8): when these diphenols were oxidised under identical conditions, (5) gave a complex intractable mixture whereas (8) gave in 67% yield the dienone (23) with the C-homoerythrinan skeleton.

Synthesis of C-homoerysodienone and its conversion into B-homoerysodienone via a dibenz[d,f]azecine; potential precursors of the homoerythrina alkaloids

C-Homoerysodienone (12) was synthesised by the unambiguous route (26)→(27)→(28)→(30)→(32)→(12) with a high-yielding oxidative phenolic coupling as the key step. The intermediate (27) was also converted via a reductive fragmentation into the dibenzazecine (9), oxidation of which gave a dienone different from (12), clearly having the 5;7-fused structure (10). A report of the synthesis of (10) by a different route is thus confirmed, and efficient routes are available to the phenols (9) and (10), likely biosynthetic precursors of the Schelhammera alkaloids.

A general approach to the synthesis of phenanthrenoid compounds. An alternative to oxidative phenolic coupling

A general approach to the synthesis of phenanthrenoid compounds. An alternative to oxidative phenolic coupling

Oxidative phenol coupling with cupric-amine complexes

Oxidative phenol coupling with cupric-amine complexes

Evidence of two distinct mechanisms for CC or CO bond formation in the oxidative coupling of phenols

AbstractThe oxidation of 2, 6‐xylenol by oxygen, catalysed by a copper complex, leads to poly‐phenylene ether or quinones according to the amount of added pyridine. The first oxidation step is common in the two processes giving aryloxy radicals. The pH of the medium plays a fundamental role so that at low values a second electron is removed and the diradical rearranges into a cation in acidic medium. This cation may add to the monomer or to H2O thus explaining the production of several quinones. It has been shown that in methanol solvent, a nucleophilic reagent, addition to the cation takes place giving a new product which was characterised by thin layer chromatography (tlc).

Formation of dityrosine cross-links in proteins by oxidation of tyrosine residues

1. 1.|Enzymic oxidation of proteins with peroxidase and hydrogenperoxide at a basic pH value leads to an oxidative phenolic coupling of adjacent tyrosine residues forming cross-linked proteins. 2. 2.|Dityrosine (3,3′-bityrosine) was identified as the cross-link in oxidised proteins by thin-layer chromatography, amino acid analysis and fluorescence measurements. 3. 3.|Gel filtration experiments with oxidised insulin showed that the cross-linkage is predominantly intermolecular. 4. 4.|In tetranitromethane treated proteins, dityrosine could be identified after hydrolysis.

Design of the substrate for oxidative phenol coupling: An efficient dienone synthesis

Design of the substrate for oxidative phenol coupling: An efficient dienone synthesis

First observed oxidative phenol coupling to the β-position of a chalcone

2′,4-Dihydroxy-4′,6′-dimethoxy-trans-chalcone couples at the β-position with 3,5-dimethoxyphenol under oxidative conditions to form stereoisomeric 2-[α-(4-hydroxy-2,6-dimethoxyphenyl)-4-hydroxybenzyl]-4,6-dimethoxybenzo [b]furan-3(2H)-ones.

Molecular spectrometric studies of complexes copper-pyridine catalysts of the oxidative coupling of phenols—I. Electronic and EPR studies of the catalytic complex

The EPR and optical spectra of compounds copper(I) chloride—pyridine-O 2, catalysts of the oxidative coupling polymerization reaction of 2,6 dimethyl phenol have been investigated. Analysis of the e.p.r. spectra indicate that, for active complexes in solution, the sigma bonding is appreciable covalent. A program relating the electronic and magnetic properties has shown that these complexes are varying from tetragonally elongated octahedrons, the ground state being d x 2– y 2 , to nearly square planar arrangement (negligible axial coordination). In the solid state, the complexes would be orthorhombic. In all cases, the active species would present CuO bonds.

Molecular spectrometric studies of complexes copper-pyridine catalysts of the oxidative coupling of phenols—II. Kinetic and infrared studies

Kinetic and quantitative infrared studies of the copper (I) Chloride—pyridine system in various solvents have allowed to determine the stochiometric composition, i.e., 1 CuCl, 1 Py, 1 2 O 2, and the solubilities of the complexes obtained. Assignments of the CuCl, CuN and CuO i.r. modes have been made and the effect of coordination on the fundamental vibrations of pyridine investigated. It appears that the copper acts through an oxidation—reduction cycle and that the oxygen bridge of the complex is the active part. The observed monomer—pyridine association would likely control the selectivity. The nature of the various compounds during the oxidative coupling of 2,6-dimethylphenol hea been studied by i.r. and u.v. experiments.

Synthetic Approach to Pakistanamine by Phenolic Oxidative Coupling

Synthetic Approach to Pakistanamine by Phenolic Oxidative Coupling

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

The coordination complexes (CuCl, pyridine, methanol) used for oxidative coupling – study by high resolution NMR determination of the structure of the catalyst

AbstractA structure of the solid catalyst used for oxidative coupling of phenols is proposed from an NMR study in various solvents. The stoichimetry of the solid prepared via oxidation of Cu2Cl2 by O2 in a pyridine/methanol mixture is discussed in view of the coordination of the ligands. The catalytic activity could be due to the magnified image group and the exchangeability of the pyridine ligands.

Intramolecular oxidative phenol coupling. III. Two-electron oxidation with thallium(III) trifluoroacetate

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTIntramolecular oxidative phenol coupling. III. Two-electron oxidation with thallium(III) trifluoroacetateMartin A. Schwartz, Bernard F. Rose, and Baburao. VishnuvajjalaCite this: J. Am. Chem. Soc. 1973, 95, 2, 612–613Publication Date (Print):January 1, 1973Publication History Published online1 May 2002Published inissue 1 January 1973https://doi.org/10.1021/ja00783a064RIGHTS & PERMISSIONSArticle Views978Altmetric-Citations72LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InReddit PDF (247 KB) Get e-Alerts Get e-Alerts

Synthesis of thomasic acid

Thomasidioic acid ( 2) has been synthesized in two steps by oxidative phenol coupling of sinapic acid ( 6) to the dilactone ( 7) followed by acid-catalyzed rearrangement. The diol dibenzyl ether ( 15), derived from thomasidioic acid dimethyl ester ( 9) by benzylation followed by LAH reduction, was selectively oxidized to yield thomasic acid ( 1) after debenzylation and base hydrolysis.

Application of Phenolic Oxidation to the Total Syntheses of the Isoquinoline and Related Alkaloids; Biogenetic Type Synthesis

Oxidative radical coupling of phenols between the phenolic oxygen atom or a carbon atom ortho or para to the hydroxy group and those of another phenol to form C-C or C-O bonds is called phenolic oxidation. This type of reaction plays an important role in the biogenesis of many natural products. The present article gives a survey of the total synthesis of isoquinoline alkaloids by phenolic oxidation. 1. Simple Isoquinoline Alkaloids 2. 2-Benzylisoquinoline Series 3. 1-Benzylisoquinoline Series 3.1. Cularine and Related Alkaloids 3.2. Bis-benzylisoquinoline Alkaloids 3.3. Aporphine and Proaporphine Alkaloids 3.4. Dibenzopyrrocoline Alkaloids (Indolo[2,1-a]isoquinoline Alkaloids) 3.5. Morphinanedienone Alkaloids 3.6. Erythrina Alkaloids 3.7. Phenanthroquinolizidine Alkaloids 4. Amaryllidaceae Alkaloids 5. Phenethylisoquinoline Alkaloids

Biosynthesis of magnoflorine from reticuline by direct oxidative coupling

Magnoflorine (2) has been shown by tracer experiments to be derived from reticuline (1) in Aquilegia plants, presumably via direct oxidative phenol coupling; labelled norprotosinomenine produced no incorporation of radioactivity, thus excluding a mechanism involving the dienone (3a).

Some Studies of Oxidative Coupling of Phenols

Some Studies of Oxidative Coupling of Phenols

Vernetzung von Phenolcarbonsäureestern von Polysacchariden durch oxydative phenolische Kupplung

AbstractGuaran, a watersoluble polysaccharide, was esterified with various phenolic acids. Solutions of these esters formed gels upon oxidation. In these gels the phenolic ester groups were crosslinked by oxidative phenolic coupling, the corresponding dimeric phenolic acids being liberated by saponification.

Formation of indole derivatives by phenolic oxidative coupling

Ferric chloride oxidation of 3-hydroxy-4-methoxyphenethylamine (3) and N-(3-hydroxy-4-methoxyphenethyl)-ethylamine (6) afforded the corresponding indole derivatives (10) and (11), respectively, in moderate yield. The synthesis of the indole derivative (13) from N-(3-hydroxybenzyl)dopamine (7) by phenolic oxidative coupling with potassium ferricyanide is also described.