A new synthesis of α-fluorovinylsulfones utilizing the Peterson olefination methodology

α-Fluoro-α-silyl-substituted sulfones 1 are readily prepared from fluoromethyl phenyl sulfone and the appropriate silyl chloride. The use of TBSCl improves both the stability and yield of 1. Lithium derivatives 4 undergo a smooth Peterson olefination reaction with less-enolizable carbonyl compounds to give moderate to good yields of the expected α-fluorovinylsulfones 6, in some cases with high E-stereoselectivity. One-pot reaction with 4 generated in situ from fluoromethyl phenyl sulfone in tetrahydrofuran (THF) also proceeds smoothly, particularly with aldehydes.     

Argadin, a new chitinase inhibitor, produced by Clonostachys sp. FO-7314

A new chitinase inhibitor, designated as argadin (1), was isolated from the cultured broth of a fungal strain FO-7314. The strain was identified as Clonostachys sp. from the morphological characteristics. Argadin was purified from the cultured mycelium by a combination of cation exchange, adsorption and gel filtration chromatographic methods. The structure of argadin was elucidated as cyclo(Nomega-acetyl-L-arginyl-D-prolyl-homoseryl-histidyl-L- 2-aminoadipyl) in which homoseryl gamma-methylene bonded to histidyl alpha-amino residue. The IC50 value of argadin against Lucilia cuprina (blowfly) chitinase was 150 nM at 37 degrees C and 3.4 nM at 20 degrees C. Argadin arrested the moult of cockroach larvae upon injection into the ventral abdominal part.     

Stability characteristics of transition layer solutions

The multiple existences and their stability properties of stationary solutions with a single transition layer in some scalar reaction-diffusion equation are shown. Each solution is constructed by using classical singular perturbation methods and its stability property is determined by a simple algebraic quantity, say index, appearing in the construction of a solution.     

Numerical simulation of natural convection of latent heat phase-change-material microcapsulate slurry packed in a horizontal rectangular enclosure heated from below and cooled from above

A two-dimensional numerical simulation of natural convection in a rectangular enclosure heated from below and cooled from above has been conducted with non-Newtonian phase-change-material (PCM) microcapsulate slurry with latent heat capacities. The formulation of the mathematical model in dimensionless co-ordinates and discretization of the governing equations have been done using the finite volume method. Both natural convection and heat transfer characteristics are discussed about natural convection with PCM microcapsulate slurry, which exhibits the pseudoplastic non-Newtonian fluid behavior and a peak value in the specific heat capacity with latent heat. The viscosity of the present PCM microcapsulate slurry is assumed to follow the Ostwald-de Waele power law fluid model with the power-law index n and the consistency coefficient K. The effects of phase-change material, the mass concentration, and the aspect ratio Ar on the natural convection heat transfer are described, respectively. By comparing with the results of microcapsule slurry without phase change, the enhancement in heat transfer is found in microcapsule slurry with phase change during the phase change temperature range. Numerical simulations are performed in the following parametric ranges: the width–height aspect ratio of the enclosure Ar from 2 to 20, the mass concentrations C _m of the slurry from 10 to 40%, power law index n of the slurry from 0.89 to 1.0 and Rayleigh numbers Ra ranges from 10³ to 10⁷.     

Changes on distribution of absorbed dose rates in air in an urban area after the Fukushima Daiichi Nuclear Power Plant accident

Journal of Radioanalytical and Nuclear Chemistry - Tokatsu area was on one pathway of the radioactive plumes released in the Fukushima Daiichi Nuclear Power Plant accident and absorbed dose rate in...     

Photoresponsive Stripe Pattern in Achiral Azobenzene Liquid Crystals

A periodic stripe pattern is found in the nematic phase close to the smectic phase of photoresponsive achiral liquid‐crystalline compounds. The origin of the stripe patterns can be ascribed to an extremely large bent elastic constant K₃₃. In addition, we succeeded in controlling the pattern by the following two methods: 1) the stripe disappears by a trans–cis photoisomerization upon UV light irradiation and reappears upon light termination, and 2) the stripe pattern is stabilized over the whole nematic phase, at approximately 10 °C, by polymerization of the compounds.     

Highly efficient synthesis of optically pure 5,5',6,6',7,7',8,8'-octahydro-1,1'-bi-2-naphthol and -naphthylamine derivatives by partial hydrogenation of 1,1'-binaphthyls with carbon nanofiber supported ruthenium nanoparticles

Use of Ru/CNF-P, nanoruthenium particles dispersed on a nanocarbon fiber support, realizes highly efficient catalytic partial hydrogenation of 1,1'-bi-2-naphthol and -naphthyl-amine derivatives. The reactions proceed in high turnover numbers without racemization of the axial chirality, offering a practical procedure for the production of optically pure 5,5',6,6',7,7',8,8'-octahydro-1,1'-binaphthyls in good to high yields.     

Facile synthesis of medium-sized cyclic amines based on Friedel-Crafts reaction via iminium cation by use of acetylene dicobalt complex

An intramolecular Friedel-Crafts reaction of N-methoxymethyl sulfoneamides 3e-j containing an acetylene dicobalt moiety was found to proceed smoothly to afford eight- and nine-membered cyclic amines 4e-j in high yields.     

Unusual behavior of CMC for binary mixtures of alkyltrimethylammonium bromides: dependence on chain length difference

The critical micelle concentrations (CMC) of binary mixtures of alkyltrimethylammonium bromides (CnTAB) were measured by a conductivity method. The CMCs of C12TAB-C14TAB and C14TAB-C16TAB systems exhibit the usual behavior, namely a monotonic decrease of the CMC with the mole fraction of the longer chain surfactant. However, the CMC behaviors of C10TAB-C16TAB, C11TAB-C16TAB, C12TAB-C16TAB, and C11TAB-C14TAB are unusual. The behaviors of the CMCs with mole fraction for these systems consist of three regions, of which the first is characterized by a very small decrease of the CMC in the range of low mole fraction, followed by a second where there is an abrupt decrease of the CMC, and a third where the CMCs exhibit their usual behavior. The molecular interaction parameter omega is almost equal to zero for mixtures that have the usual CMC behavior, but is small and positive for those systems with unusual CMCs. We infer that for very low mole fractions of C16TAB, the C16TA ion in the C12TAB-C16TAB system penetrates imperfectly into the micelle and its two methylene groups exist outside the micelle.