The photochemical synthesis of 4-acyl-1,2-dimethyl-3H-phenothiazin-3-ones

4-Acyl-1,2-dimethyl-3H-phenothiazin-3-ones were prepared by the photochemical reaction of 1,2-dimethyl-3H-phenothiazin-3-one with aldehydes. The structures of the newly prepared compounds were determined by elemental analysis, spectroscopic methods (ir, nmr and ms) and comparison with a sample prepared by an alternate route.     

Reversal of diastereofacial selectivity in the intramolecular michael addition of -α-carbamoyloxy-α,β-unsaturated esters. Synthesis of N-benzoyl-D,L-daunosamine

Contrary to the precedents, 1,3-anti stereoselection was found in the intramolecular Michael addition of ethyl $\text{threo}$,5-carbamoyloxy-4-trialkylsilyloxy-2-hexenoate to culminate in a synthesis of N-benzoyl-$\text{D}$,$\text{L}$-daunosomine. The antiperiplanar effect due to the group at 4-position was revealed to play a major role in the stereoselection in this type of reactions. N-benzoyl-$\text{D}$,$\text{L}$-3-epidaunosamine was also synthesized by 1,2-syn asymmetric induction.     

Fabrication of PbTiO3 Ceramic Fibers by Sol-Gel Processing

The sol-gel processing was applied to the fabrication of PbTiO₃ fibers. Pb(CH₃COO)₂·3H₂O and Ti(OC₃H ₇ ⁱ )₄ were refluxed with stirring in 2-methoxyethanol to form Pb-methoxyethoxide and Ti-methoxyethoxide, respectively, followed by mixing with stirring in 2-methoxyethanol to form Pb−Ti double alkoxide. The hydrolysis and polycondensation reaction of this double alkoxide gave polymerized products, and as a result the viscosity of the solution increased, suggesting that linear polymers were produced through the hydrolysis and polycondensation reaction. Homogeneous PbTiO₃ gel fibers were drawn from the spinnable viscous solutions, which were wellcrystallized into perovskite type PbTiO₃ at 650°C. The heat-treated fibers were a few centimeters long and from 10 to 100 μm in diameter. The fiber was made up of extremely uniform grains. Electron diffraction revealed a preferred growth of (101) planes along the fiber axis, which might be due to the linear molecular characteristics of the alkoxide.     

Copper-catalyzed allylation of carbonyl derivatives using allyl(2-pyridyl)silanes

[reaction: see text] We have developed an efficient copper-catalyzed allylation of carbonyl derivatives using allyl(2-pyridyl)silanes, in which the strong directing effect of the 2-pyridyl group was observed. A useful synthesis and allylation of substituted allyl(2-pyridyl)silanes is also described.     

Self-ordering process of phenanthrene polyesters observed by the simultaneous DSC-XRD method

Phase transition behavior of polyesters derived from 2,7-phenanthrene dicarbonic acid diethylester and alkanediols with even methylene carbon number was investigated by the simultaneous DSC-XRD method. The smectic A phase was observed on cooling from the molten state. The transition entropy from the isotropic state to the smectic A phase was about 9.0 J mol^-1 K^-1, which depended on the methylene carbon number. The linear expansion coefficients, based on the (001) spacing of the crystalline phase at room temperature, were 1.3·10^-4 K^-1 (crystalline phase), 5.7·10^-4 K^-1 (crystallization region), 1.7·10^-3 K^-1 (smectic A phase) during cooling, and 1.5·10^-4 K^-1 (crystalline phase), and 1.0·10^-3K^-1(melting region) on heating. This revised version was published online in July 2006 with corrections to the Cover Date.     

Enantioselective reduction of ketones with optically active 2,2′-diamino-6,6′-dimethylbiphenyl-lithium aluminum hydride complex

Enantioselective reductions of prociral ketones with chiral hydride reagent prepared from optically active 2,2′-diamino-6,6′-dimethylbiphenyl and lithium aluminum hydride were accomplished in O.Y. more than 50%.     

Effects of type of adsorption isotherms on parallel diffusion of sulfonated dyes into porous cellulose membrane

Transport phenomenon of three sulfonated azo dyes, C.I. Acid Red 88, C.I. Direct Yellow 12, and C.I. Direct Blue 15 into water-swollen cellulose membranes has been analyzed on the basis of parallel transport theory by surface and pore diffusion. Langmuir equation was applied into the mass balance equation to estimate dye concentration in the pores. The results were compared with the results obtained by applying Freundlich equation in our previous papers. The surface diffusivity (D _s) and the pore diffusivity (D _p) for the parallel diffusion model obtained by applying Langmuir equation agreed with those obtained by applying Freudlich equation. The theoretical concentration profiles for parallel diffusion calculated usingD _s andD _p coincided accurately with the experimental data when we applied either Langmuir or Freundlich equations.     

Poly(dimethylsilylene-co-diphenylsilylene)

In this work several polyorganosilylenes were synthesized including homo-and copolymers containing SiMe₂ and SiPh₂ units. A Wurtz-type coupling reaction of the respective dichlorodiorganosilanes with sodium metal, varying the Ph₂SiCl₂/Me₂SiCl₂ ratio was the chosen synthesis method. Products with different characteristics for solubility, structure (cyclic or linear), composition, and molecular weight distribution could be obtained depending on the comonomer ratios employed. The polysilane derivatives were characterized by infrared spectroscopy (IR), proton nuclear magnetic resonance (¹H-NMR), and gel permeation chromatography (GPC). Valuable information related to the comonomers' reactivities was obtained, such as molecular weight distribution, composition, and relationships between yields of soluble, insoluble, and cyclic materials of each polycondensation reaction. © 1992 John Wiley & Sons, Inc.     

Porphyrin acids

The structural change from the porphyrin free base to monoacid and diacid by successive protonation has been studied by the IR, visible and NMR spectroscopy. The results have indicated that the cation and anion of the porphyrin diacid are strongly associated through H-bonding. The far IR spectra show especially marked differences in the free base, monoacid, and diacid due to the changes of the inner core of the porphyrin ring.