Oxidation of 1-methyl-1H-imidazole-2-thiol with chlorine dioxide

Oxidation of 1-methyl-1H-imidazole-2-thiol with chlorine dioxide was performed for the first time, and the results were shown to depend on the oxidation conditions. Optimal conditions were found for the preparation of 1-methylimidazole-2-sulfonic acid, 2,2′-disulfanediylbis(1-methylimidazole) hydrochlorite, and 1-methyl-3-sulfo-3H-imidazolium chloride. A new salt, 4-methylanilinium 1-methyl-1H-imidazole-2-sulfonate, was isolated.     

Electrochemical oxidation of catechol in the presence of 2-thiouracil: application to electro-organic synthesis

The electrochemical oxidation of catechol in the presence of 2-thiouracil (as a nucleophile) has been studied in aqueous solutions using cyclic voltammetry and controlled-potential coulometric techniques. The results indicate that catechol participating in a 1,4 (Michael) addition reaction converts to a new thiadiazafluorenone compound. The electrochemical synthesis of this compound has been successfully performed in an undivided cell in a good yield and purity and was characterized by IR, ¹H and ¹³C NMR, mass spectrometry and elemental analysis.     

Electrochemical oxidation of some catechol derivatives in the presence of some betadicetone derivatives: mechanistic and thermodynamic study

Electrochemical oxidations of 4-methylcatechol (1), 4-tert-butylcatechol (5) and catechol (7) in the presence of different nucleophiles have been investigated both experimentally and theoretically. Experimental results have been obtained by means of cyclic voltammetry and controlled-potential coulometry. Also the theoretical results were calculated at DFT (B3LYP) level of theory and 6–311+G (p, d) basis set. The calculated results indicate that oxidation potential of catechols (1, 5, 7) and their substituted species are directly dependent on the ?G _tot, and continuance of reactions during electrolysis is dependent on ?G _tot of produced species on the surface of electrode. The current study indicates that theoretical studies along with empirical research can be useful in displaying electrochemical reaction mechanisms.     

Electrochemical oxidation of catechol in the presence of cyclopentadiene. Investigation of electrochemically induced Diels-Alder reactions

We describe the synthesis and kinetic evaluation of compounds from [4 + 2] alone and [4 + 2] followed by [2 + 2] cycloaddition reactions of electrochemically generated o-benzoquinone with 1,3-cyclopentadiene.     

Electrochemical synthesis of heterocyclic compounds. XII. Anodic oxidation of catechol in the presence of nucleophiles

The electrochemical synthesis of coumestan derivatives and some related heterocyclic system ( 2a-11a ) by anodic oxidation of catechol ( 1 ) in the presence of various nucleophiles 2-11 is described. Products were obtained in good yields and purity. The mechanism of oxidation was deduced from voltammetric data and by coulometry at controlled potential.     

Electrochemical behavior of catechol in the presence of 2-methyl-1,3-cyclopentanedione: application to electrosynthesis

Abstract  Electro-oxidation of catechol in the presence of 2-methyl-1,3-cyclopentanedione as a nucleophile was investigated in water–acetonitrile (90:10 v/v) solution. The results indicate that the o-benzoquinone electrogenerated participates in a Michael addition reaction with this nucleophile. The electrosynthesis of 2-(3,4-dihydroxyphenyl)-2-methylcyclopentane-1,3-dione was carried out. The product was characterized by NMR, MS, FT-IR, and elemental analysis. An EC mechanism was deduced from voltammetric and spectroscopic data. Also, the Michael addition reaction rate constant (k _m) was estimated using digital simulation of voltammograms. Graphical abstract   Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorized users.     

Electrochemical behavior of catechol in the presence of 2-methyl-1,3-cyclopentanedione: application to electrosynthesis

Abstract  

Electro-oxidation of catechol in the presence of 2-methyl-1,3-cyclopentanedione as a nucleophile was investigated in water–acetonitrile (90:10 v/v) solution. The results indicate that the o-benzoquinone electrogenerated participates in a Michael addition reaction with this nucleophile. The electrosynthesis of 2-(3,4-dihydroxyphenyl)-2-methylcyclopentane-1,3-dione was carried out. The product was characterized by NMR, MS, FT-IR, and elemental analysis. An EC mechanism was deduced from voltammetric and spectroscopic data. Also, the Michael addition reaction rate constant (k _m) was estimated using digital simulation of voltammograms.     

Electrochemical oxidation of catechol in the presence of indole: a facile and one-pot method for the synthesis of trisindolyl-o-benzoquinone

The electrochemical oxidation of catechol has been studied in the presence of indole as the nucleophile in water/acetonitrile (50:50) using cyclic voltammetry and controlled-potential coulometry methods. The results revealed that the quinone derived from the oxidation of catechol participates in Michael addition reactions with indole, and via a novel ECECECE mechanism, converts it to the trisindolyl-o-quinone in a good yield via electrochemical oxidation under controlled-potential conditions without any toxic reagents at the carbon electrode in a two-compartment cell.     

Electrochemical oxidation of catechols in the presence of ethyl‐2‐chloroacetoacetate. Synthesis and mechanistic study

Electrochemical oxidation of catechol and some of 3‐substituted catechols ( 1a‐c ) has been studied in the presence of ethyl‐2‐chloroacetoacetate ( 3 ) in water/acetonitrile (90:10) solution using cyclic voltammetry and controlled‐potential coulometry. The results indicate that the quinones derived from catechols ( 1a‐c ) participate in Michael addition reactions with ethyl‐2‐chloroacetoacetate( 3 ), with consumption of only two electrons per molecule of 1 , to form the corresponding benzofurans ( 10a‐c ). The electrochemical synthesis of benzofurans ( 10a‐c ) has been successfully performed at a carbon rod electrode and in an undivided cell with good yields and purity. A new two‐electron mechanism for the electrode process is proposed.     

Electrochemical and kinetic study of the coupling reaction between 4-nitroso and 4-hydroxylaminopyridine-1-oxide

The study of the reduction process of nitrosopyridine-1-oxide at platinum electrodes in aqueous solution by controlled potential coulometry is reported. The results obtained are consistent with the hypothesis that a pH dependent reaction takes place between the depolarizer and the reduction product. Such results have been confirmed by conventional kinetic experiments. The pH dependence of the rate constant can be accounted for in terms of a base catalyzed mechanism.     

Synthesis of 2-Methyl-4-quinolyl Isothiocyanate

A procedure has been developed for the synthesis of substituted 2-methylquinolin-4-ylthiuronium salts by reaction of 2-methyl-4-chloroquinoline with N-substituted thioureas. Alkaline hydrolysis of these salts yields 2-methyl-4-quinolyl isothiocyanate instead of the expected 2-methylquinoline-4-thiol.     

Quantum Chemical Study of the Mechanism of Formation of a Fused Heterocyclic System from 4,5-Dihydro-1H-imidazole-2-thiol and 1-Iodopropan-2-one

Russian Journal of Organic Chemistry - Five possible paths of the formation of imidazo[2,1-b][1,3]thiazole fused heterocyclic system in the reaction of 4,5-dihydro-1H-imidazole-2-thiol with...     

Polyfunctional imidazoles: VI. Synthesis of 2-amino-1-aryl-4-chloro-1H-imidazole-5-carboxylic acids derivatives

Aryl-2,4-dichloro-5-formylimidazoles by a successive treatment with hydroxylamine and thionyl chloride were converted into 1-aryl-2,4-dichloroimidazole-5-carbonitriles which by the action of sodium azide and tin(II) chloride were transformed into 2-amino-1-aryl-4-chloroimidazole-5-carbonitriles. The consecutive reactions of 2-azido-1-aryl-4-chloro-5-formylimidazoles with N-bromosuccinimide, methanol, or amides led to the formation of methyl esters and amides of 2-azido-1-aryl-4-chloroimidazole-5-carboxylic acids. The reduction of the latter with tin(II) chloride resulted in the corresponding derivatives of 2-amino-1-aryl-4-chloroimidazole-5-carboxylic acids, and the reduction of 2-azido-1-aryl-4-chloroimidazole-5-carboxylic acids was accompanied with decarboxylation and yielded 2-amino-1-aryl-4-chloroimidazoles.     

3-甲基-4-乙氧甲酰-2-环己烯酮合成方法的改进

甲基乙氧羰基环己烯酮;多聚甲醛;3-甲基-4-乙氧甲酰-2-环己烯酮合成方法的改进     

Oxygenation of 4-tert-butylcatechol catalysed by a manganese(II) complex: implications for extradiol catechol dioxygenases

An N donor tetradentate manganese complex, [Mn^II(bispicen)Cl₂] (A) [bispicen = N,N-bis(2-pyridylmethyl)-1,2-ethanediamine)] catalyses the oxidative cleavage of 4-tert-butylcatechol (1) in the presence of O₂. The oxygenated products were isolated by t.l.c. and column chromatography and characterised by ¹H-, ¹³C-n.m.r., DEPT, i.r. and u.v.–vis. spectroscopy. The oxygenated products as well as other spectral evidence suggest that the oxygenation occurs via a 4-tert-butylsemiquinone bound complex, [Mn^II(bispicen)(4-sq)]⁺ (4-sq = 4-tert-butylsemiquinone). ¹H-n.m.r. spectroscopy suggests that the oxygenation follows multiple pathways. Isolation of the products suggests that the oxygenations proceed in an extradiol fashion and a probable mechanism is suggested. Some intradiol cleaved products have also been detected. E.s.r. spectroscopy suggests that manganese(II) is ultimately converted into the manganese(IV) species.     

Electrochemical study of catechol and some 3-substituted catechols in the presence of 4-hydroxy coumarin: application to the electro-organic synthesis of new coumestan derivatives

Electrochemical oxidation of catechol (1d), 3-methylcatechol (1a), 3-methoxycatechol (1b) and 2,3-dihydroxybenzoic acid (1c) in the presence of 4-hydroxycoumarin as nucleophile in aqueous solution has been studied using cyclic voltammetry and controlled-potential coulometry. The results indicate that (1a–1d) participating in a 1,4 (Michael) addition reaction convert to coumestan derivatives (5a–5d). The electrochemical synthesis of 5a–5d has been successfully performed in an undivided cell in good yield and purity.     

4—甲基—7—巯基—2（1H）—喹啉酮的合成

以间氨基苯硫酚为起始原料,与乙酰乙酸乙酯一步环合得目标产物4－甲基－7－巯基－2（1H)-喹啉酮（4）,收率：22％;以间苯二胺为起努原料,经乙酰乙酸乙酯环合,重氮化,二硫化合物的形成及盐酸锌和粉还原获得目标产物4,收率：59％。     

Investigation of the electro-oxidation and oxidation of catechol in the presence of sulfanilic acid

The electrochemical oxidation of catechol (1) in the presence of sulfanilic acid (2) was investigated. Some electrochemical (EC) techniques such as cyclic voltammetry and controlledpotential coulometry were used. The oxidation reaction of catechol (1) with periodate in the presence of sulfanilic acid (2) was also investigated spectrophotometrically. The results indicate that the o-quinone derived from catechol participate in Michael addition reaction with sulfanilic acid (2). In addition, according to the ECE mechanism, the observed homogeneous rate constant (k _obs) for the reaction ofo-quinone derived from catechol (1) with sulfanilic acid (2) has been estimated by digital simulation of cyclic voltammograms.     

Ruthenium(VI) in the oxidation of 2-propanol and 1-propanol: A kinetic study

Transition Metal Chemistry - Sodium ruthenate catalyses the oxidation of 2-propanol by hexacyanoferrate(III) ([Fe(CN)6]3?), diperiodato-cuprate(III) (DPC), periodate $ (IO_{4}^{-}) $ and...