Synthesis and new rearrangements of 4-isoxazolin-4,5-dicarboxylic acid derivatives

Acyclic nitrones react with dimethyl acetylenedicarboxylate (DMAD) to give stable isoxazolines, from which the ones that contain electron-donating aromatic rings at the C3 position (R¹) were shown to undergo unprecedented fragmentation at room temperature, giving the R¹-aldehyde and inseparable product mixtures, probably due to the formation of highly reactive species such as iminocarbenes. Attempts to convert the isoxazolines to the corresponding stable azomethine ylides, by refluxing in toluene, again led to the same product mixtures as above (e.g., the room temperature decomposition). Isoxazolines when reacted with methoxide at room temperature afforded highly functionalised diastereomeric mixtures. Also, isoxazolines, when reacted with propylamine, gave the corresponding amides regioselectively, all of which were more stable than the parent isoxazolines.     

Lu2O3对球形Ni(OH)2高温充放电性能的影响

为了改善镍电极的高温充电效率，采用机械混合的方式将球形Ni(OH)2与不同比例的Lu2O3混合后制成粘结式镍正极。充放电测试、循环伏安和XRD等实验结果表明，掺杂Lu2O3后镍电极的析氧过电位明显提高，高温充电效率得到了很大改善，在充电后的电极中β-NiOOH生成；而且Lu2O3的掺杂比例对镍电极的高温性能在不同的充放电倍率下有不同程度的影响，3．5％是最好的掺杂比例，掺杂对高温小电流充电效率的改善作用要大于高温大电流充电。     

固体超强酸（SO4^2-／ZrO2）的异丁烷／1-丁烯烷基化反应性能和失活研究

研究了固体超强酸(SO4^2-／ZrO2)催化剂的酸性及异丁烷-1-丁烯烷基化反应性能，结果表明，固体超强酸的酸性与焙烧温度有关，适当提高焙烧温度有利于样品酸强度的提高，但焙烧温度过高会导致脱硫，使样品酸强度和酸量降低，固体超强酸的异丁烷／1-丁烯烷基化催化反应活性与其酸性相对应，酸性强，反应活性高，但催化剂的活性衰减很快，这是催化剂表面的快速积炭所致。     

Tetrakis(thiadiazolo)porphyrazines. 3. Acid-base Properties and Stability of Tetrakis-3,4-(1,2,5-thiadiazolo)porphyrazine in Sulfuric Acid Solutions

AM1 calculations gave the proton affinities of different types of donor sites in tetrakis-3,4-(1,2,5-thiadiazolo)porphyrazine, H₂{[SN₂)₄PA}, and protonation of the meso-nitrogen atoms was found to be favored. A spectrometric study showed that the basicity of the meso-nitrogen atoms of the porphyrazine macrocycle is strongly diminished and these atoms in CF₃CO₂H are involved in an incomplete acid-base interaction (ABI) to give acid solvates, while a complete ABI (protonation) is found only in the presence of sulfuric acid. The basicity constants of the meso-nitrogen atoms were determined spectrophotometrically in CF₃CO₂H-H₂SO₄. The kinetics of decomposition of the macrocyclic chromophore in concentrated sulfuric acid was studied and a possible mechanism for this process was proposed.__________Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 2, pp. 278–287, February, 2005.     

Synthesis and characterization of oligo-4-[(pyridin-3-ylimino)methyl]phenol

The oxidative polycondensation of 4-[(pyridin-3-ylimino)methyl]phenol (4-PIMP) with O₂, H₂O₂, and NaOCl was studied in an aqueous alkaline medium between 50°C and 90°C. Oligo-4-[(pyridin-3-ylimino)methyl]phenol (O-4-PIMP) prepared was characterized by ¹H-NMR, ¹³C-NMR, FT-IR, UV-VIS, size-exclusion chromatography, and elemental and thermal analyses techniques. At the optimum reaction conditions, the yield of O-4-PIMP was 18.9%, 39.4%, and 46.8% using H₂O₂, O₂, and NaOCl oxidant, respectively. According to the TG analysis, the initial degradation temperature of O-4-PIMP was 218°C, which was by 50°C higher than that of 4-PIMP. Thermal analyses of 4-PIMP and O-4-PIMP were carried out in N₂ atmosphere at 15–1000°C. The highest occupied molecular orbital, the lowest unoccupied molecular orbital, and electrochemical energy gaps of 4-PIMP and O-4-PIMP were determined from the onset potentials for n-doping and p-doping, respectively. Also, optical band gaps of 4-PIMP and O-4-PIMP were determined according to UV-VIS measurements.     

MoO3、NiO、ZnO在小表面金红石上的分散行为

Dispersion of MoO3, NiO, ZnO on rutile TiO2 with low specific surface area was studied with Mercury Porosimeter, SEM, XPS and Ammonia Extraction method. The dispersion thresholds of MoO3, NiO, ZnO on three rutile TiO2 carriers were obtained with XPS, and com-pared with those on anatase TiO2 with high specific surf are area. Ammonia Extraction method was used to identify the surface oxide species interarting with support surface in different strength and it was found that the proportions of oxides that can not be extracted by ammonia extraction are different for MoO3, NiO and ZnO which are supported on rutile TiO2.     

Sulfide oxygenation by tert-butyl hydroperoxide with mononuclear (Me3TACN)Mn catalysts

Mononuclear (Me₃TACN)MnX₃ compounds, where X is Cl⁻, Br⁻, or N₃⁻, and Me₃TACN is 1,4,7-N,N′,N″-trimethyl-1,4,7-triazacyclononane, have been tested for catalyzing both sulfide oxygenation and styrene epoxidation by tert-butyl hydroperoxide (TBHP) and display turnover frequencies (TOF) up to 200 h⁻¹ at room temperature. Sulfoxides or sulfones may be produced selectively by varying reaction conditions. Product distribution from the oxygenation reactions of ethyl phenyl sulfide, 2-chloroethyl phenyl sulfide, and styrene is consistent with a mechanism involving an early single-electron transfer (SET) step.     

Novel Synthesis of 1,2,3-Triazoles via 1,3-Dipolar Cycloadditions of Alkynes to Azides in Ionic Liquid^＋

2-Azido-3,5-dichloropyridine and 2-azido-5-chloro-3-fluoropyridine were given by reaction of sodium azide with 2,3,5-trichloropyridine, 3,5-dichloro-2-fluoropyridine or 5-chloro-2,3-difluoropyridine in ionic liquids. 1,3-Dipolar cycloaddition of 2-azido-3,5-dichloropyridine or 2-azido-5-chloro-3-fluoropyridine to alkynes in ionic liquids afforded the corresponding 1,4,5-trisubstituted [1,2,3]-triazoles in good yields and regioselectivities.     

Unusual reaction of α-diketones of the indole series with hydrazine

Symmetrical and unsymmetrical α-diketones of the indole series were synthesized by the Friedel-Crafts reaction of 3-indolylglyoxyl chlorides with heterocycles. A nonconventional reaction of N-unsubstituted diketones with hydrazine producing 3H-pyrazolo[3,4-c]quinoline derivatives was found. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 5, pp. 862–866, May, 2006.