Cationic carbohydroxylation of alkenes and alkynes using the cation pool method

The reactions of an N-acyliminium ion pool with alkenes and alkynes gave gamma-amino alcohols and beta-amino carbonyl compounds, respectively, after treatment with H(2)O/Et(3)N. The present reaction serves as an efficient method for cationic carbohydroxylation of alkenes and alkynes. When vinyltrimethylsilane was used as an alkene, the reaction was highly diastereoselective and served as an access to an enantiomerically pure alpha-silyl-gamma-amino alcohol. [reaction: see text]     

Infrared and raman studies on the phase structure of barium ethyl(octyl)phosphate-water system

Barium ethyl(alkyl)phosphates, as new simple surfactants ((C₂H₅O)(RO)-PO ₂ ^– )₂Ba²⁺ with various chain length ofR, were synthesized. The infrared spectra in the CH stretching region were measured for these surfactants in the solid state and in aqueous solution, and assignments were made. In particular, the ordering and environment of octyl chains in the different phases of the barium ethyl(octyl)phosphate-water system were studied by the Fourier-transform-infrared and Raman spectra. The CH stretching bands in the infrared spectra reflected the ordering and environment of octyl chains in each phase. The Raman band connected to the PO ₂ ^– symmetric stretching mode was sensitively shifted. This was caused by the change of aggregation structures with different Ba²⁺...PO ₂ ^– interaction. The infrared band arising from the PO ₂ ^– antisymmetric stretching mode was insensitive to the phase structures. The C–C stretching region in the infrared spectra was used to discuss the ordering of each phase.     

New functional microspheres with active succinimide groups

Radiation-induced polymerization of monomers, for example N-methacryl-oxysuccinimide (MASu) and diethylene glycol dimethacrylate (2G), in ethyl propionate, was performed from +25°C to –78°C. The copoly (MASu/2G) microspheres were obtained in MASu monomer compositions of 30 wt % or below. The average particle diameter of copoly(MASu/2G, 20/80 wt %) microspheres obtained at irradiation temperatures of 25°, 0°, and –43 °C were 0.81±0.29, 0.63±0.26, and 0.90±0.43 m, respectively. No microspheres were formed when irradiated at –78 °C. The reactivity of the succinimide groups on the surface of copoly(MASu/2G, 20/80 wt%) microspheres was checked by reacting with ethylene diamine. The maximal amount of reacting succinimide groups was 9.4±0.5 nol/g, which corresponds to about 1 % of the total number of succinimide groups in the microsphere.     

Kunzeanones A, B, and C: novel alkylated phloroglucinol metabolites from Kunzea ambigua

Three new metabolites, kunzeanones A (1), B (2), and C (3), along with three known compounds, cryptostrobin (4), (+)-spathulenol (5), and (−)-globulol (6), were isolated from the non-polar fraction of the dried leaves of Kunzea ambigua (Myrtaceae), which shows ichthyotoxicity toward a small fish, medaka. The structures of these new compounds were elucidated as condensates of alkylated phloroglucinol with methylflavanone and germacrane-type sesquiterpene, respectively, on the basis of spectral analyses including 1-D and 2-D NMR spectra. The stereochemistries of kunzeanones A and B were determined by X-ray crystallographic analysis. A sesquiterpene, (+)-spathulenol (5), among the isolates was characterized as the ichthyotoxic principle of the extract.     

Reduction of Cu2+ to Cu+ in Xerogels Prepared from (3-Aminopropyl)Trimethoxysilane

Silica gels doped with Cu²⁺ ions were prepared from the (3-aminopropyl) trimethoxysilane (APTMOS)/tetraethoxysilane (TEOS) systems. Sols showed a broad absorption peak at 640 nm, suggesting 3–5 coordination of the aminopropyl groups to Cu²⁺. For gels prepared from APTMOS and dried at room temperature, the 640 nm peak decreased and a red-shifted absorption appeared below 400 nm within a few months. The luminescence spectra of the xerogels showed emission bands at 430–470 and 510 nm. The former and latter bands are ascribed to Cu⁺ monomer and dimer emissions, respectively. These results indicate that Cu²⁺ ions are reduced to Cu⁺. When xerogels were prepared from APTMOS/TEOS = 1 (vol/vol), the color of xerogels was blue with an absorption peak at around 670 nm, indicating no reduction of Cu²⁺ ions.     

Enantioselective Protonation of Cyclic Carbonyl Ylides by Chiral Lewis Acid Assisted Alcohols

Chiral Lewis acid-catalyzed asymmetric alcohol addition reactions to cyclic carbonyl ylides generated from N-(α-diazocarbonyl)-2-oxazolidinones featuring a dual catalytic system are reported. Construction of a chiral quaternary heteroatom-substituted carbon center was accomplished in which the unique heterobicycles were obtained in good yields with high stereoselection. The alcohol adducts were successfully converted to optically active oxazolidine-2,4-diones by hydrolysis. Mechanistic studies by DFT calculations revealed that alcohols could be activated by Lewis acids, enabling enantioselective protonation of the carbonyl ylides.     

Effect of Static Magnetic Field on Photocatalytic Degradation of Methylene Blue over ZnO and TiO2 Powders

Magnetic field effects (MFEs) on photocatalytic degradation of methylene blue (MB) solution over ZnO and TiO₂ powders are investigated under static magnetic field up to 0.7 T with light irradiation by ultraviolet (UV) light emitting diode. The UV–visible-near-infrared spectrometer is used to monitor the MB concentrations. The positive MFE is observed for ZnO, while the negative MFE for TiO₂, and both MFEs are increased with the increase in the magnetic field applied. By increasing the settling time (the time interval between the preparation of MB solution and the powder dispersion into the MB solution), the photodegradation abilities under MFEs are decreased for both the catalysts. The cause of MFE is discussed in terms of dissolved oxygen in the MB solution and magnetic adsorption of the constituent molecules.     

Mapping analyses of Fe-diffused mc-Si using M?ssbauer microscope and photoluminescence

Twenty CK chondrites collected in the Antarctica Continent were characterized by inductively-coupled plasma mass spectrometry (ICP-MS), prompt gamma ray analysis (PGA), instrumental neutron activation analysis (INAA), X-ray diffractometry (XRD) and ⁵⁷Fe-M?ssbauer spectroscopy. As a result of elemental analysis, it was revealed that 18.2~26.4 mass% of iron was included in the each chondrite. M?ssbauer spectrum of LEW86258, classified as a typical CK chondrite, was found to be composed of two paramagnetic doublets and two magnetic sextets. M?ssbauer spectra were assigned to the absorption due to forsterite (Mg_1.36Fe_0.64SiO₄) and magnetite (Fe₃O₄), as also confirmed by XRD. XRD study of LAP03834, reclassified from CK to R chondrite, revealed the presence of crystalline phase due to forsterite. These results indicate that LAP03834 and related chondrites, i.e., MET01149, LAP03923 and MAC02453, should be reclassified as R or LL chondrite.