Two directions of the reaction of 3,4-dihydroxy-6-oxoalka-2,4-dienoic acid esters with anthranilic acid hydrazide

Methyl 3,4-dihydroxy-6-oxoalka-2,4-dienoates reacted with anthranilic acid hydrazide to give methyl [5-alkyl-1-(2-aminobenzamido)-2-hydroxy-3-oxo-2,3-dihydro-1H-pyrrol-2-yl]acetates. The reaction of anthranilic acid hydrazide with ethyl 3,4-dihydroxy-6-oxohepta-2,4-dienoate afforded ethyl (2Z)-(3a-hydroxy-2-methyl-10-oxo-3,3a,5,10-tetrahydro-4H-pyrazolo[5,1-c][1,4]benzodiazepin-4-ylidene)acetate as solvate with one methanol molecule. The structure of the isolated compounds was determined on the basis of IR and NMR spectra and X-ray diffraction data.     

Two directions in spiroheterocyclization of 1H-pyrrole-2,3-diones upon the action of 3-arylamino-1H-inden-1-ones

4-Ethoxycarbonyl-5-phenyl-substituted 1H-pyrrole-2,3-diones react with 3-arylamino-1H-inden-1-ones in the ratios 1: 1 and 1: 2 to form substituted spiro{indeno[1,2-b]quinoline-10,3??-pyrroles} and substituted spiro{diindeno[1,2-b:2??,1??-e]pyridine-11,3??-pyrroles}, respectively.     

间硝基苯甲醛或间氯苯甲醛与芳香胺和芳香酮的Mannich反应

间硝基苯甲醛或间氯苯甲醛与芳香胺和芳香酮在20~25℃和催化量的浓盐酸催化下能直接进行Mannich反应, 用一步合成法合成15个1-芳基-3-芳胺基(3-硝基苯基)丙酮。产率为68~87%。产物结构经元素分析, IR, ^1H NMR, MS鉴定。本文还讨论了反应的适宜条件。     

The reaction between 3-aminocrotonates and oxindole-3-ylidene derivatives: synthesis of highly substituted pyrroles

The reaction between 3-aminocrotonates and 3-acetonylideneoxindole in refluxing toluene resulted in 2-pyrrolo-3′-yloxindoles in high yields (around 90%). At room temperature the 2-pyrrolo-3′-yloxindoles exists as keto-enol tautomers. Treatment with POCl₃ yielded the 2-chloro-3-pyrrolyl indole, which gave the pyrrolo annulated indolopyran-2-one upon basic hydrolysis of 2-chloro-3-pyrrolyl indole methyl ester.     

Room temperature rate coefficient for the reaction between CH3O2 and NO3

The molecular modulation spectroscopic technique was employed to study the kinetics of NO₃ radicals produced in the 253.7 nm photolysis of flowing gas mixtures of HNO₃/CH₄/O₂ at room temperature. By computer fitting of the NO₃ temporal behavior, a rate coefficient of (2.3 ± 0.7) × 10^?12 cm³ molecule^?1 s^?1 was obtained for the reaction between NO₃ and CH₃O₂ at 298 K.     

The specificity of the colour reaction between ammonia and 3-phenyl-2-thiohydantoin

The colour reaction between 3-phenyl-2-thiohydantoin and ammonia is studied quantitatively. Determinations of 0.1–0.6 μmoles of 3-phenyl-2-thiohydantoin are possible with a precision close to 2%. In analyses of amino acid mixtures for glycine after conversion to 3-phenyl-2-thiohydantoin, only derivatives of serine and threonine interfere to a slight extent. The specificity of the primary colour reaction with ammonia, and the structural requirements for it are discussed; a structure for the pigment species is proposed.     

Rate coefficient for the reaction between NO3 radicals and dimethyl sulphide

The rate coefficient for reaction between NO₃ and dimethyl sulphide has been measured to be (1.0 ± 0.2) × 10⁻¹² cm⁻³ molecule ⁻¹ s⁻¹ independent of temperature between 278 and 318 K. No evidence was found for a reaction channel producing NO₂ and dimethyl sulphoxide.     

Base-catalyzed reaction between isatins and N-Boc-3-pyrrolin-2-one

The base-catalyzed reaction between isatins and N-Boc-3-pyrrolin-2-one yields Morita–Baylis–Hillman (MBH) adducts instead of the expected aldol products in good to high yields (up to 97%). Various organic and inorganic bases are efficient catalysts for this reaction. Our study excluded the Morita–Baylis–Hillman mechanism for the formation of the MBH-type products. The MBH products are most likely formed as a result of the subsequent isomerization of the original aldol products between isatins and N-Boc-3-pyrrolin-2-one.     

Study of interface diffusion and reaction between Zr3N4 and stainless steel

The effect of annealing treatment on the interface diffusion and reaction between Zr₃N₄/stainless steel was studied by AES depth profiling along with line shape analysis. The Zr₃N₄ film was deposited on stainless‐steel substrates by reactive magnetron sputtering. Scanning electron microscopy, electron diffraction, AES and UV–VIS reflection were performed to characterize the deposited film. The results indicated that the interface diffusion between Zr₃N₄ and stainless steel took place during deposition and can be promoted by annealing treatment, but no interface reaction took place before or after annealing treatment. High‐temperature and long‐time annealing treatment resulted in obvious oxidation of the Zr₃N₄ layer. The UV–VIS reflection results indicated that the absorption band of Zr₃N₄ film shifted to shorter wavelength after annealing treatment. Copyright © 2003 John Wiley & Sons, Ltd.     

Association reaction between SiH3 and H2O2: a computational study of the reaction mechanism and kinetics

The association reaction between silyl radical (SiH₃) and H₂O₂ has been studied in detail using high-level composite ab initio CBS-QB3 and G4MP2 methods. The global hybrid meta-GGA M06 and M06-2X density functionals in conjunction with 6-311++G(d,p) basis set have also been applied. To understand the kinetics, variational transition-state theory calculation is performed on the first association step, and successive unimolecular reactions are subjected to Rice–Ramsperger–Kassel–Marcus calculations to predict the reaction rate constants and product branching ratios. The bimolecular rate constant for SiH₃–H₂O₂ association in the temperature range 250–600 K, k(T) = 6.89 × 10^?13 T ^?0.163exp(?0.22/RT) cm³ molecule^?1 s^?1 agrees well with the current literature. The OH production channel, which was experimentally found to be a minor one, is confirmed by the rate constants and branching ratios. Also, the correlation between our theoretical work and experimental literature is established. The production of SiO via secondary reactions is calculated to be one of the major reaction channels from highly stabilized adducts. The H-loss pathway, i.e., SiH₂(OH)₂ + H, is the major decomposition channel followed by secondary dissociation leading to SiO.     

Nonlinear chemical reaction between Na2S2O3 and Peroxide compound

Kinetics of reaction between Na₂S₂0₃ and peroxide compound (H₂0₂ or Na₂S₂O₃) in a batch reactor and in a continuous stirring tank reactor (CSTR) were studied. Steady oscillations in uncatalyzed reactions in a CSTR were first discovered. In Na₂S₂0₃-H₂O₂-H₂S0₄ reaction system, Pt potential and pH of higher and lower flow rates beyond oscillation flow rates were in around the same extreme values. The reaction catalyzed by Cu²⁺ consists of the catalyzed oscillation process and the uncatalyzed osciliation one. On the basis of experiment, a reaction mechanism consisting of three stages was put forward. The three stages are H⁺ positive-feedback reactions, proton negative-feedback (uncatalyzed negative-feedback and catalyzed negative-feedback) reactions and transitional reactions. The mechanism is able to explain reasonably the nonlinear chemical phenomena appearing in the thiosulfate oxidation reaction by peroxide compounds. Project supported by the National Natural Science Foundation of China.     

Nonlinear chemical reaction between Na_2S_2O_3 and Peroxide compound

Kinetics of reaction between Na2S2O3 and peroxide compound ( H2O2 or Na2S2O8) in a batch reactor and in a continuous stirring tank reactor (CSTR) were studied.Steady oscillations in uncatalyzed reactions in a CSTR were first discovered.In Na2S2O3-H2O2-H2SO4 reaction system,Pt potential and pH of higher and lower flow rutes beyond oscillation flow rates were in around the same extreme values.The reaction catalyeed by Cu2+ corsist of the catalyzed oscillation process and the uncatalyzed osciliation one.On the basis of experiment,a reaction mechanism consisting of three stages was put forward.The three stages are H positive-feedback reactions,proton negative-feedba k (uncatalyzed negative-feedback and catalyzed negative-feedback) reactions and transitional reactions.The mechanism is able to explain reasonably the nonlinear chemical phenomena appearing in the thiosulfatc oxidation reaction by peroxide-compounds.     

Two directions of interaction of 2-aryl-1,2,3,4-tetrahydropyridine-3,3,4,4-tetracarbonitriles with nucleophiles

Depending on the reaction conditions, 2-aryl-1,2,3,4-tetrahydropyridine-3,3,4,4-tetracarbonitriles react with alcohols, thiols and ketoximes to give 3-amino-4-aryl-1,1-di[R-oxy(thio)]-6,7-dialkyl-3a,4,5,7a-tetrahydro-1H-pyrrolo[3,4-c]pyridine-3a, 7a-dicarbonitrles or 2-aryl-5,6-dialkylpyridine-3,4-dicarbonitriles.Chuvash State University, Cheboksary 428015. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 3, pp. 367–375, March, 1997.     

H原子与CH3NH2抽氢反应的动力学计算

用QC ISD(T)/6-311 G(3DF,3PD)/MP2/6-311G(D,P)方法研究了H原子与CH3NH2的抽氢反应过程。该反应包含两个反应通道:H分别从CH3基团(R1)和NH2(R2)基团上抽氢。R1势垒比R2势垒低3.42kJ/mol,表明R1是主反应通道。在从头算的基础上,用变分过渡态理论(CVT)加小曲率隧道效应(SCT)研究了各反应温度范围为200~4000K内的速率常数,所得结果与实验值符合的很好。动力计算表明,在所研究的温度范围内,变分效应对速率常数的计算影响不大,而在低温范围内,隧道效应起了很重要的作用。     

The gas-phase reaction between O3 and HO radical: a theoretical study.

We report a theoretical study on the reaction of ozone with hydroxyl radical, which is important in the chemistry of the atmosphere and in particular participates in stratospheric ozone destruction. The reaction is a complex process that involves, in the first stage, a pre-reactive hydrogen-bonded complex (C1), which is formed previous to two transition states (TS1 and TS2) involving the addition of the hydroxyl radical to ozone, and leads to the formation of HO4 polyoxide radical before the release of the products HO2 and O2. The reaction is computed to be exothermic by 42.72 kcal mol(-1), which compares quite well with the experimental estimate, and the energy barriers of TS1 and TS2 with respect to C1 are computed to be 1.80 and 2.26 kcal mol(-1) at 0 K. A kinetic study based on the variational transition state theory (VTST) predicts a rate constant, at 298 K, of 7.37 x 10(-14) cm3 molecule(-1) s(-1), compared to the experimentally recommended value of 7.25 x 10(-14) cm3 molecule(-1) s(-1).