21086-65-7Relevant academic research and scientific papers
Synthesis of 4, 5-Dimethoxy-o-benzoquinone by formal [4+2] cyclization of 2, 3-dimethoxy-1, 3-butadiene with oxalyl chloride
MroB, Gerson,Langer, Peter
, p. 189 - 190 (2009)
The cyclization of 2, 3-dimethoxy-1, 3-butadiene with oxalyl chloride provides a new method for the synthesis of 4, 5-dimethoxy-o-benzoquinone. 2009. Bentham Science Publishers Ltd.
A divergent and selective synthesis of ortho- and para-quinones from phenols
Huang, Zheng,Kwon, Ohhyeon,Esguerra, Kenneth Virgel N.,Lumb, Jean-Philip
, p. 5871 - 5885 (2015/08/04)
Abstract We describe a divergent synthesis of substituted ortho- and para-quinones by catalytic aerobic oxygenation of phenols. Substituted quinones are omnipresent in chemistry and biology, but their synthesis frequently suffers from low efficiency and poor scope. Our methodology employs a catalytic aerobic di-functionalization of phenols to aryloxy-ortho-quinones. Regioselective substitution with an alcohol provides the alkoxy substituted ortho- or para-quinone, while hydrolysis affords the para-hydroxyquinone. These are mild and selective conditions for the synthesis of diversely substituted quinones from readily available phenol starting materials.
Synthesis, structure, and reactivity of [Cu(phen)2]ClO 2: Aerobic oxidation of Cl- to ClO2- at room temperature
Hossain, Md. Munkir,Tseng, Mei-Chun,Lee, Chi-Rung,Shyu, Shin-Guang
, p. 36 - 40 (2014/01/17)
An unusual 4e- oxidation of Cl- into ClO 2- occurred during the reaction between CuCl and phenanthroline (phen) in air to form a [Cu(phen)2]ClO2 complex, which is capable of oxidizing catechol into the highly substituted pentenone derivative methyl 1-hydroxy-2-oxo-4,5,5-trimethoxycyclopent-3-ene-1- carboxylate through contraction of the aromatic ring by extradiol C-C bond cleavage concomitant with the further formation of a C-C bond. Copyright
Synthesis, structure, and reactivity of [Cu(phen)2]ClO2: Aerobic oxidation of Cl- to ClO2- at room temperature
Hossain, Md. Munkir,Tseng, Mei-Chun,Lee, Chi-Rung,Shyu, Shin-Guang
, p. 36 - 40 (2015/04/27)
An unusual 4e- oxidation of Cl- into ClO2- occurred during the reaction between CuCl and phenanthroline (phen) in air to form a [Cu(phen)2]ClO2 complex, which is capable of oxidizing catechol into the highly substituted pentenone derivative methyl 1-hydroxy-2-oxo-4,5,5-trimethoxycyclopent-3-ene-1-carboxylate through contraction of the aromatic ring by extradiol C-C bond cleavage concomitant with the further formation of a C-C bond. The copper(II)-catalyzed aerobic oxidation of Cl- to ClO2- to form the [Cu(phen)2]ClO2 (phen = phenanthroline) complex at room temperature is reported. The oxidation of catechol by using [Cu(phen)2]ClO2 yields methyl 1-hydroxy-2-oxo-4,5,5-trimethoxycyclopent-3-ene-1-carboxylate including 4,5-dimethoxy-1,2-benzoquinone
Total synthesis and biological evaluation of the nakijiquinones
Stahl,Kissau,Mazitschek,Huwe,Furet,Giannis,Waldmann
, p. 11586 - 11593 (2007/10/03)
The Her-2/Neu receptor tyrosine kinase is vastly overexpressed in about 30% of primary breast, ovary, and gastric carcinomas. The nakijiquinones are the only naturally occurring inhibitors of this important oncogene, and structural analogues of the nakijiquinones may display inhibitory properties toward other receptor tyrosine kinases involved in cell signaling and proliferation. Here, we describe the first enantioselective synthesis of the nakijiquinones. Key elements of the synthesis are (i) the reductive alkylation of a Wieland - Mieschertype enone with a tetramethoxyaryl bromide, (ii) the oxidative conversion of the aryl ring into a p-quinoid system, (iii) the regioselective saponification of one of the two vinylogous esters incorporated therein, and (iv) the selective introduction of different amino acids via nucleophilic conversion of the remaining vinylogous ester into the corresponding vinylogous amide. The correct stereochemistry and substitution patterns are completed by conversion of two keto groups into a methyl group and an endocyclic olefin via olefination/reduction and olefination/isomerization sequences, respectively. This synthesis route also gave access to analogues of nakijiquinone C with inverted configuration at C-2 or with an exocyclic instead of an endocyclic double bond. Investigation of the kinase-inhibiting properties of the synthesized derivatives revealed that the C-2 epimer 30 of nakijiquinone C is a potent and selective inhibitor of the KDR receptor, a receptor tyrosine kinase involved in tumor angiogenesis. Molecular modeling studies based on the crystal structure of KDR and a model of the ATP binding site built from a crystal structure of FGF-R revealed an insight into the structural basis for the difference in activity between the natural product nakijiquinone C and the C-2 epimer 30.
The kinetics of lignin reactions during chlorine dioxide bleaching. Part 1. Influence of pH and temperature on the reaction of 1-(3,4-dimethoxyphenyl)ethanol with chlorine dioxide in aqueous solution
Gunnarsson, N. Per-Ivar,Ljunggren, Sten C. Hj.
, p. 422 - 431 (2007/10/03)
Rate constants as well as the products formed from the reaction between chlorine dioxide and the non-phenolic lignin model compound 1-(3,4-dimethoxyphenyl)ethanol have been determined in the pH interval 3-8. Spectroscopic data for the substrate and some products are given. The pH of the reaction mixture has a large influence on both the rate constant and the product distribution. Under technical chlorine dioxide bleaching conditions (pH 3, 40°C and an ionic strength of 0.3 mol kg-1 ) the rate constant has been found to be 0.12(2) M-1 s-1, which corresponds to a half-life of approximately 7 min in 0.01 M solution. The influence of temperature [Ea = 29(7)kJ mol-1] on the rate of reaction of this lignin model is small. At acidic pH (35) a large variety of both oxidized (quinones, lactones and ketones) and chlorinated products are formed. Above pH 8, one oxidation product, 3,4-dimethoxyacetophenone, predominates. No chlorinated products are found at a high pH. The mechanisms of formation of all these products are discussed. Acta Chemica Scandinavica 1996.
A SIMPLE ROUTE TO 4,5-DIALKOXY-o-QUINONES BY CATALYTIC OXIDATION OF PHENOL
Prati, Laura,Rossi, Michele
, p. 83 - 86 (2007/10/02)
A convenient synthesis of 4,5-disubstituted-o-quinones from phenol and alcohols through copper-mediated activation of molecular oxygen is reported.The influence of different experimental conditions on the reaction products is evaluated.
Iron Porphyrin-Catalyzed Oxidation of 1,2-Dimethoxyarenes: A Discussion of the Different Reactions Involved and the Competition between the Formation of Methoxyquinones or Muconic Dimethyl Esters
Artaud, Isabelle,Ben-Aziza, Khaled,Mansuy, Daniel
, p. 3373 - 3380 (2007/10/02)
This paper describes the oxidation of an α,β-diarylpropane lignin dimer model and other dimethoxyarenes by several iron porphyrin-based biomimetic systems.From 1-(3,4-dimethoxyphenyl)-2-phenylpropanol (1), three types of products are identified: the 3,4-dimethoxybenzaldehyde derived from the Cα-Cβ cleavage of the propyl side chain and either quinones or muconic dimethyl esters resulting from oxidations at level of the dimethoxyaryl group.The selectivity of the reaction is discussed with respect to the nature and reactivity of the high-valent iron-oxo species formed upon reaction of the oxidants, H2O2 or magnesium monoperoxyphthalate (MMP), with the iron porphyrins.Fe(TF5PP)Cl-catalyzed oxidation of 1 by H2O2 in an aprotic medium (CH3CN/CH2Cl2), yields a clean "lignin peroxidase-like" reaction with selective formation of the aldehyde.In an aqueous buffered solution, MMP oxidation of para-substituted 1,2-dimethoxyarenes catalyzed by an iron tetrakis(pentafluorophenyl)-β-tetrasulfonatoporphyrin, Fe(TF5PS4P), clearly depends on the electronic properties of the para-substituent.The reaction is selective for para-quinone formation in the case of an electron-releasing group and for muconic dimethyl ester formation in the case of an electron-withdrawing group.
Method for dyeing keratinous fibres using an aminoindole in combination with a quinone derivative
-
, (2008/06/13)
Method for dyeing keratinous fibres, characterized in that at least one composition (A) containing at least one aminoindole in a medium appropriate for dyeing is applied to these fibres, the application of the composition (A) being preceded or followed by the application of a composition (B) containing, in a medium appropriate for dyeing, at least one quinone derivative chosen from ortho- or para-benzoquinones, ortho- or para-benzoquinone monoimines or diimines, 1,2- or 1,4-naphthoquinones, ortho- or para-benzoquinone sulphonimides, α,ω-alkylene-bis-1,4-benzoquinones, or 1,2- or 1,4-naphthoquinone monoimines or diimines, the aminoindoles and the quinone derivatives being chosen such that the difference in redox potential ΔE between the redox potential Ei of the aminoindoles, determined at pH 7 in a phosphate medium on a vitreous carbon electrode by voltametry, and the redox potential Eq of the quinone derivative, determined at pH 7 in a phosphate medium by polarography on a mercury electrode relative to the saturated calomel electrode, in such that
Iron porphyrin catalyzed oxidation of lignin model compounds: the oxidation of veratryl alcohol and veratryl acetate
Cui, Futong,Dolphin, David
, p. 2314 - 2318 (2007/10/02)
meso-Tetra(2,6-dichloro-3-sulfonatophenyl)porphyrin iron chloride catalyzes the oxidation of 3,4-dimethoxybenzyl alcohol (veratryl alcohol) in aqueous solution to give veratraldehyde along with demethoxylation and ring-cleavage products.The isolation of a direct ring-cleavage product from the oxidation of veratryl acetate in aqueous solution supports the previously proposed ring-cleavage mechanisms.The oxidation in methanol, however, does not lead to ring-cleavage products.When veratryl alcohol was oxidized in methanol, solvent was found to be incorporated into the 3-position of veratryl alcohol, giving new insight into the mechanism of oxidation.
