3,3,3-Trifluoro-2,2-dihydroxypropanesulfonamides as building blocks for trifluoromethyl-containing pyrazoles and benzimidazoles

1-Alkyl-3-trifluoromethylpyrazole-4-sulfonamides 10 , (2-trifluoromethyl-2,3-dihydrobenzimidazol-2-yl)methanesulfonamides 12 , and (2-benzimidazolyl)metbanesulfonamides 13 were prepared starting from 3,3,3-trifluoro-2,2-dihydroxypropanesulfonamides 1 .     

Treatment of dye wastewater by using photo-catalytic oxidation with sonication

The degradation of Acid Orange 52 in aqueous solutions was investigated by using three processes (photocatalysis, sonolysis, and photocatalysis with sonication). In the case of photocatalysis, although the concentration of Acid Orange 52 decreased to 35% in 480 min, the color of the solution was not disappeared. In the case of sonolysis, it was decomposed completely in 300 min, but the total organic carbon concentration decreased down by only about 13% in 480 min. In the case of photocatalysis with sonication, the concentration of Acid Orange 52 reached to 0 in 240 min and the total organic carbon concentration decreased by about 87% in 480 min. These results indicate that the ultrasonic irradiation enhanced the photocatalytic degradation. The addition of chloride ion (50 ppm) into Acid Orange 52 solution decreased the decomposition efficiency for photocatalysis. In the cases of sonolysis and photocatalysis with sonication, the decomposition efficiency did not change significantly by the addition of chloride ion. These results indicate that chloride ion disturbs the photocatalysis of dye, but the decomposition of dye using the irradiation of ultrasound is not influenced by chloride ion. From these results, it is considered that the photocatalysis with sonication is most effective for the decomposition of dye in the three processes in this study.     

High temperature pyrolysis of methane in shock waves. Rates for dissociative recombination reactions of methyl radicals and for propyne formation reaction

The pyrolysis of 2% CH₄ and 5% CH₄ diluted with Ar was studied using both a single–pulse and time–resolved spectroscopic methods over the temperature range 1400–2200 K and pressure range 2.3–3.7 atm. The rate constant expressions for dissociative recombination reactions of methyl radicals, CH₃ + CH₃ → C₂H₅ + H and CH₃ + CH₃ → C₂H₄ + H₂, and for C₃H₄ formation reaction were investigated. The simulation results required considerably lower value than that reported for CH₃ + CH₃ → C₂H₄ + H₂. Propyne formation was interpreted well by reaction C₂H₂ + CH₃ → P-C₃H₄ + H with ?? = 6.2 × ¹⁰12 exp(?17 kcal/RT) ^cm3 mol^?1 s^?1.     

A Theoretical Study of Pure and Mixed Spin-Polarized Tritium and Helium Triatomic Systems Using Hyperspherical Coordinates

Pure and mixed spin-polarized tritium ( ${{\rm T}\uparrow}$ ) and helium (He) triatomic systems are studied using hyperspherical coordinates. A slow variable discretization approach is adopted to solve the nuclear Schrödinger equation, in which the Schrödinger equation in hyperangular coordinates is solved using basis splines at a series of fixed FEM-DVR hyperradii. By using the best empirical interaction potentials, we study comparatively the bound states of ( ${{\rm T}\uparrow}$ )₃, ⁴He( ${{\rm T}\uparrow}$ )₂, ${^4{\rm He}_2{\rm T}\uparrow}$ , ⁴He₃ and ${^4{\rm He}_2^3{\rm He}}$ in the J ^Π = 0⁺ symmetry. The bound state energy levels are calculated for all these molecular species except ⁴He( ${{\rm T}\uparrow}$ )₂, for which we have found no bound state. The calculated wave functions of these species are found all to exhibit a very large spatial extension, indicating the diffuse nature of these bound states. The molecular structure of these species will also be calculated and analyzed in detail.     

Synthesis of the core ring system of awajanomycin from N-Boc-3-methoxycarbonyl-2-pyridinone

Awajanomycin, which was isolated from marine-derived fungus, possesses unique structural features and cytotoxic activity against A549 cells. Due to its unique structure, no total synthesis has yet been reported, and neither the relative stereochemistry nor the absolute configuration has been determined. We report the synthesis of the core ring system of awajanomycin, which includes: (i) regioselective addition of the acetate unit onto C4-position of N-Boc-3-methoxycarbonyl-2-pyridinone; (ii) stereoselective installation of a hydroxyl group on C3-position; and (iii) stereo- and regioselective epoxide-opening reaction by Me₃Al.     

Statistics of rare strong bursts in autocatalytic stochastic growth with diffusion

A general model of autocatalytic stochastic growth with diffusion is analytically and numerically investigated. Exact analytical results for the intermittency exponents and the probability of rare strong bursts in an infinite system are presented. Finite-size saturation effects, leading to the stretched exponential growth of statistical moments, are further considered. These analytical predictions are checked in numerical simulations.