Production of Superoxide Ion with Carbon Gas-Diffusion-Electrode And Reaction of Superoxide Ion with Aromatic Halide

Superoxide ion O~-_2 is prepared in aprotic media by carbon gas-diffusion-electrode for the first time. The experimental results indicate that this electrode is superior to carbon plane-electrode in the reaction of O~-_2 with p-bromonitrobenzene. When the gas-diffussion-electrode is used, the yield of the product nitrophenol increases by 20%, and the selectivity of the reaction is nearly doubled as compared with the plane-electrode.     

Room temperature phosphorescence of α-bromonaphthalene induced by β-cyclodextrin in the presence of cyclohexane

β-Cyclodextrin (β-CD) can induce a-bromonaphthalene (BrN) to emit strong room temperature phosphorescence (RTP) in the presence of micro amounts of cyclohexane (c-hexane). Experiments of luminescence spectra, phosphorescence lifetime and fluorescence polarization prove the formation of c-hexane/β-CD/BrN ternary inclusion complex. The apparent formation constant of the ternary inclusion complex was determined and the effect mechanism of c-hexane on the RTP of BrN induced by β-CD is discussed.     

Cyclization Reaction of α-Triazolyl-α, β-unsaturated Ketones with Phenyl hydrazine

InourpreviousworkwehavereportedthestudiesonthereactionofvinyItriazolcderivativeswithhydroxylamine,andfOundthatcycloadditiontookp1aceandthenewheterocycliccompoundsl,2-oxazocyclopentaneshavingplant-growthregulatingactivitywereobtainedl,2.InordertosynthesizenewheterocycliccompoundsandtosearchfOrnewcompoundshavingbioactivity,thereactionofa-triazolyl-a,ll-unsaturatedketones(Z)-or(E)-4,4-dimethyl-1-aryl-2-(l,2,4-triazol-l-yl)-l-penten-3-onesI.-bwithphenylhydrazinewasstudied.Theresultshowedthatcycl…     

Reaction of β-acyl-β-nitrostyrenes with benzenethiols

β-Acetyl- and β-benzoyl-β-nitrostyrenes reacted with benzenethiols under mild conditions to give previously unknown 4-aryl-4-(arylsulfanyl)-3-nitrobutan-2-ones and 3-aryl-3-(arylsulfanyl)-2-nitro-1-phenylpropan-1-ones, respectively, which were isolated as pure diastereoisomers or mixtures of two diastereoisomers.     

Kinetics of the Reaction of 2-Chloro-quinoxaline with Hydroxide Ion in ACN–H2O and DMSO–H2O Binary Solvent Mixtures

The kinetics of alkaline hydrolysis of 2-chloroquinoxaline (QCl) with hydroxide ion was investigated spectrophotometrically at different percentages of aqueous–organic solvent mixtures with acetonitrile (10–60% v/v) and with dimethylesulphoxide (10–80%) over the temperature range from 25 to 45 °C. The reaction was performed under pseudo first order conditions with respect to 2-chloroquinoxaline (QCl). An increase in the percentage of organic solvent (v/v) has different effects on the reaction rate constants, presumably due to hydrogen bond donor and acceptor differences of the media and other solvatochromic parameters. The data were discussed in terms of the Kamelt-Taft parameter and E _T(30). A nonlinear relation between the logarithm of the rate constant and reciprocal of the dielectric constant suggests the presence of selective solvation by the polar water molecules. Activation parameters ΔH ^#, ΔS ^# and ΔG ^# were determined and discussed.     

Study on Room-Temperature Phosphorescence of 1-Bromonaphthalene in Media of Surfactant and β-Cyclodextrin

CvcIodextrmsofutionsandnncellaTsolutionsareextenforeh'usedasthemediafoTtheat-tainmenofRTPAnUmbe1ofgrouPshavepresenedtheirworkonRThinthel;-=Howexler.feuhteraturesdeahwitbRTPintheededmediatwoseparate9'steunHowexler.feuhteraturesdeahwitbRTPintheededmediaofcyclodexirinsandedctansr'Jhidswork,acoInPrehentwestud}'ontheeffectofedctantsonRTPwasundertakeninaeratedaqueouso-CDsolUtions.Thepmposeistoad1'anceunderstandingofRTPandpro1ddefavorableinfonnationforapplicationofRTh.Ansdrictalltstrigge…     

Enantiomeric Separation of Drugs Using Ion Interaction Reagents in Combination with β-Cyclodextrin in HPLC

This work describes the use of β-cyclodextrin (β-CD) as a mobile phase additive in combination with ion interaction reagents (IIR) for the enantioresolution of cyclopentolate, 2,6-diketopiperazine derivative and methylphenobarbital. The effect of concentration and type of IIR and temperature on retention and enantioseparation were studied. It has been found that the addition of an IIR to β-CD solution can lead to the improvement in enantioresolution. Interestingly, the most significant enhancement of enantioresolution was achieved for cyclopentolate, most probably due to its highest basicity. Also the stability constants of the complexes formed between β-CD and model compounds in the presence of IIR were estimated. Significant increase of complexation rate of cyclopentolate with β-cyclodextrin in presence of IIRs was observed.     

Gas-Chromatographic Study of Hydrazine Reaction with Metal β-Diketonates

When treated with hydrazine, metal -diketonates undergo decomposition to form the corresponding pyrazoles, irrespective of the kinetic stability of the chelates. With substituted metal chelates, the main reaction products are pyrazoles bearing in position 4 the -substituent of the compex. Other products are formed when the substituent has centers sensitive to nucleophilic substitution and/or elimination. The reaction can be used for structural assessment of the starting -diketonate.     

Reaction of β-trifluoroethoxy vinamidinium salts with carbon nucleophiles

β-Trifluoroethoxy vinamidinium salts 1 reacted smoothly with various types of the carbanions, generated by treatment of ketones, esters, amide and nitriles with LDA, to give the corresponding trifluoroethoxylated multifunctional dienamine derivatives 3 in moderate to good yields. On the other hand, the reaction of 1 with lithium acetylide and other carbanions derived from methyl compounds bearing sulfonyl, sulfinyl, and phosphonyl groups produced the corresponding α,β-unsaturated aldehydes 5 in good yields.     

Reaction of carotenoids with CCl_3OO~· by using pulse radiolysis

CCl4 as a selective toxin to liver can be metabolized into the free radical 3CClg by cyto- chrome P450 through a reductive dehalogenation. In the presence of oxygen, 3CClg reacts rapidly with O2 to form CCl3OO·[1], which reacts with various biological molecules, including DNA bases, amino acids and lipids and leads to various types of tissue injury[2]. CCl3OO· is used as a model of alkyl peroxyl radicals because it can be generated in water/alcohol solution, in which sufficient solubi…     

Reaction of 8-chloro-5,7-dinitroquinoline with β-dicarbonyl compounds

3-(5,7-Dinitroquinolin-8-yl)pentane-2,4-dione, 5-(5,7-dinitroquinolin-8-yl)pyrimidine-2,4,6-trione, and 5-(5,7-dinitroquinolin-8-yl)-2,2-dimethyl-1,3-dioxane-4,6-dione cesium salts have been synthesized by a simple and efficient procedure via C-arylation of the corresponding β-dicarbonyl compounds with 8-chloro-5,7-dinitroquinoline.     

Reaction of 2-aminopyridines with α, β-unsaturated acids

The reaction of 2-amino- and 2-amino-5-halopyridines with acrylic, methacrylic, and crotonic acids forms N-(2-pyridyl)- and N-(5-halo-2-pyridyl)--alanines and the betaines 2-amino-1-(2-carboxylatoethyl)pyridinium or 3,4-dihydropyrido[1,2-a]pyrimidin-2-ones, or their homologs.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 1, pp. 80–85, January, 1992.     

Reaction of dianions derived from β-ketoesters with epoxides-utility in the preparation of synthetically useful tetrahydrofurans

Presented here are several examples which demonstrate that ether substituents α- or β- to an epoxide ring can be tolerated in the ring-opening reaction with β-keto ester dianions. Subsequent acid-promoted cyclisation of the γ-hydroxy β-ketoesters then leads to synthetically useful tetrahydrofurans, as demonstrated by application of this approach to the preparation of (±)-methyl nonactate and (±)-methyl 8-epi-nonactate.     

Hypervalent Iodine in Synthesis XXX: Palladium-Catalyzed Reaction of Diaryliodonium Salts with β-substituted-α, β-enones

The reaction of diaryliodonium salts with β-substituted-α,β-enones in the presence of a palladium catalyst affords H_β-substituted products with excellent yields.     

Reaction of [VO(OPr)3] with hexamethyldisylthiane in the presence of β-diketones

The reaction of [VO(OPr)₃] (Pr is n-propyl) with hexamethyldisylthiane Me₃SiSSiMe₃ in the presence of β-diketones (acetylacetone (HAcac), hexafluoroacetylacetone (Hfac), and dipivaloylmethane (Dpm)), is studied. In all cases, vanadium(IV) and vanadium(III) β-diketonate complexes of different types are formed. New crystalline modification [V(Acac)₃] is obtained in the reaction with HAcac. The mixedligand vanadium(III) complex of the composition [V₂(Hfac)₂(μ-OPr)]₂ is formed with Hfac. In the presence of Dpm, the known vanadium(IV) complex [V₂O₂(Dpm)₂(μ-OPr)₂] is obtained in which two vanadyl groups VO²⁺ are linked by two bridging propoxy groups. The structures of all products are determined by X-ray diffraction analysis.