Catalytic Carbanion Reactions: Formation and Reaction of Carbanions from Ester or Amide Equivalents Using Catalytic Amounts of Bases

We describe here carbanion reactions using catalytic amounts of bases. The carbanions formed are different from conventional carbanions in which stoichiometric amounts of bases are needed for the formation. Two types of reactions using such carbanions from amide (imido) and ester equivalents are discussed.     

Facile synthesis of 2-unsubstituted benzofuran-3-carboxylates using diazo(trimethylsilyl)methylmagnesium bromide

Diazo(trimethylsilyl)methylmagnesium bromide reacted with (o-methoxyphenyl)(oxo)acetates to readily afford 2-unsubstituted benzofuran-3-carboxylates via oxonium ylides formed from the initially generated alkylidenecarbene intermediates.     

Electron acceleration in an ultraintense-laser-illuminated capillary

An ultraintense laser injected a 10 J of power at 1.053 microm in 0.5 ps into a glass capillary of 1 cm long and 60 microm in diameter and accelerated plasma electrons to 100 MeV. One- and two-dimensional particle codes describe wakefields with 10 GV/m gradient excited behind the laser pulse, which are guided by a plasma density channel far beyond the Rayleigh range. The blueshift of the laser spectrum supports that a plasma of 10(16) cm(-3) is inside the capillary. A bump at the high energy tail suggests the electron trapping in the wakefield.     

Electropolymerization of an immiscible monomer in aqueous electrolytes using acoustic emulsification

This paper reports on the novel electropolymerization of an immiscible monomer, such as 3,4-ethylenedioxythiophene (EDOT), in aqueous electrolytes using acoustic emulsification. This new methodology has many practical advantages and characteristics: (a) the formation of stable monomer droplets in aqueous electrolytes without added surfactants using ultrasonic treatment; (b) very smooth electropolymerization in aqueous electrolytes via the direct electron transfer between the electrode and the immiscible monomer droplets; (c) good conductivity after doping of the polymer film formed.     

Steady-shear viscosity of polydimethylsiloxanes over the range from the lower to the upper Newtonian region

The mechanism of non-Newtonian behavior for flow from the lower to the upper Newtonian region is explained by a modification of Graessley's theory. In the theory proposed here, a viscosity η_fric, which is based on friction between polymer segments and is almost shear-independent, is introduced in addition to Graessley's entanglement viscosity η_ent, which decreases with increasing shear rate. The theory is applied to previously obtained data on steady flow of polydimethylsiloxanes of different molecular weights. The agreement between calculated and experimental results is good. In polymers with the molecular weight above the critical molecular weight for entanglement M_c, the major contribution to viscosity near zero shear rate is η_ent. As the shear rate increases, the flow curve has an inflection where η_fric cannot be disregarded in comparison with η_ent. In the upper Newtonian region, η_fric has more influence on the viscosity than η_ent. The theory can also explain the experimental results on flow of polymers with molecular weight below M_c, which were shown to be slightly non-Newtonian in the previous paper.     

Rapid separation of humic acid in fresh waters by coprecipitation and flotation

After removal of suspended matter in 1 liter of water by flotation with a cationic surfactant, humic acid at theg/l level is separated from fulvic acid by coprecipitation with milligram quantities of iron(III) hydroxide at pH 7 followed by flotation with anionic surfactants. The iron(III) hydroxide is dissolved in 2M hydrochloric acid, and the acid-insoluble humic acid is filtered off on an ultrafilter and then dissolved in 10 ml of 0.1M potassium hydroxide solution for measurements of absorption spectra, molecular weight distribution and complexing ability. The time required for the separation is ca. 1 h.     

Studies on the syntheses of heterocyclic compounds—DXLVIII : Synthesis of a hasubanan ring system from the benzylisoquinoline reticuline

The synthesis of a cepharamine analogue (19) from reticuline (1) by phenolic oxidation is reported. Reticuline was converted into the methine base (13b), whose dihydro compound (14c) was oxidised to the seco-morphinandienone (17b). Michael-type cyclization of 17b, followed by an isomerization of the enone (18) gave the cepharamine-type compound (19).     

Giant Nernst effect in CeCoIn5

We present a study of Nernst and Seebeck coefficients of the heavy-fermion superconductor CeCoIn5. Below 18 K, concomitant with a field-dependent Seebeck coefficient, a large sublinear Nernst signal emerges with a magnitude drastically exceeding what is expected for a multiband Fermi-liquid metal. In the mixed state, in contrast with all other superconductors studied before, this signal overwhelms the one associated with the motion of superconducting vortices. The results point to a hitherto unknown source of transverse thermoelectricity in strongly interacting electrons.     

Electronic structure of the muonium center as a shallow donor in ZnO

The electronic structure and the location of muonium centers (Mu) in single-crystalline ZnO were determined for the first time. Two species of Mu centers with extremely small hyperfine parameters have been observed below 40 K. Both Mu centers have an axial-symmetric hyperfine structure along with a <0001> axis, indicating that they are located at the antibonding (AB(O, parallel )) and bond-center (BC( parallel )) sites. It is inferred from their small ionization energy ( approximately 6 and 50 meV) and hyperfine parameters ( approximately 10(-4) times the vacuum value) that these centers behave as shallow donors, strongly suggesting that hydrogen is one of the primary origins of n type conductivity in as-grown ZnO.     

Crystalline CrV0.95P0.05O4 catalyst for vapor-phase oxidation of picolines

CrV0.95P0.05O4 prepared as a pure crystalline form was found to be highly active for the vapor-phase oxidation of picolines to the corresponding aldehydes and acids in the presence of water.