An Efficient Synthesis of Sulfo Lewis X Analog Containing 1-Deoxynojirimycin 1

Abstract

Sulfo Lewis^x analog containing 1-deoxynojirimycin (13) has been efficiently synthesized. Glycosidation of ethyl 2,3,4-tri-O-benzyl-1-thio-β-D-fucopyranoside (5) with O-2,6-di-O-benzoyl-3,4-isopropylidene-β-D-galactopyranosyl)-(1→4)-2,6-di-O-benzoyl-N-benzyloxycarbonyl-1,5-dideoxy-1,5-imino-D-glucitol (4), prepared from O-β-D-galactopyranosyl-(1→4)-1,5-dideoxy-1,5-imino-D-glucitol (1) via 3 steps, and subsequent acid hydrolysis of the isopropylidene group gave the desired trisaccharide diol derivative (7) in good yield. Compound 7 was easily converted into 3′-O-sulfo Lewis^x analog (13) via 6 steps in high yield.

     

Chemical characterization of airborne particulate matter in ambient air of Nagoya, Japan, as studied by the multielement determination with ICP-AES and ICP-MS.

The multielement determination of PM(10) (airborne particulate matter smaller than 10 microm) samples, which was collected by a high volume air sampler at the urban site of Nagoya City, was carried out by inductively coupled plasma atomic emission spectrometry (ICP-AES) and inductively coupled plasma mass spectrometry (ICP-MS). The present analytical method was validated by analyzing urban particulate matter standard reference material of NIST SRM 1648. The analytical data for ca. 30 elements in PM(10) samples collected during a period from 8 September to 9 October, 2003, were obtained in the concentration range from sub-microg g(-1) to several-10 mg g(-1), but the data for 18 elements among ca. 30 elements were available for the characterization of PM(10) samples in ambient air, because of problems caused by the filter blanks. Then, the trends concerning the distributions of diverse elements in PM(10) samples were analyzed based on the enrichment factors and size distribution factors. The lithophile and siderophile elements were distributed more than 50% in coarse particle fraction (>2.1 microm), which was derived mainly from natural sources, such as soils and crustal minerals. On the other hand, chalcophile elements were distributed more than 50% in fine particle fraction (<2.1 microm), which was derived mostly from anthropogenic emission sources. The large enrichment of chalcophile elements in PM(10) samples as well as their mining influence factors (MIFs) suggested their wide use in industrial productions.     

Differences of fluorine in cements determined by photometric methods after distillation and pyrolysis.

Using a spectrophotometric method after distillation separation is a standard test method widely employed for the determination of fluorine (F) in cement. Using a flow injection (FI) method after pyrolysis separation for quantification of fluorine in cement has recently been developed. Differences between the fluorine content values obtained by each method have been noted. This paper documents the differences between fluorine content (distillation F) measured spectrophotometrically after distillation and that (pyrolysis F) determined using the FI method after pyrolysis for fourteen commercial Portland cements and identifies a factor contributing to the differences between distillation F and pyrolysis F values. A highly significant relationship existed between distillation F and pyrolysis F values for fourteen cements (r(2) = 0.998, p < 0.001).     

Tb3+-activated In2Si2O7 phosphor

Indium silicate activated by terbium was found to be an efficient phosphor with CR excitation, the luminosity of which was comparable to the most luminous of other terbium-activated silicates. For the preparation of this phosphor, alkaline earth metal flourides proved to act as a good mineralizer. The best result was obtained when a mixture of 1 mol In₂O₃, 2.2 mol SiO₂, 0.015 mol Tb₄O₇ and 0.05 mol BaF₂ was fired at 1 400°C in air for 4 h. Other rare earth luminescent centers such as Ce, Pr, Eu, Dy, Er and Tm were examined but none showed noticeable emission. Some UV excitation properties are also described.     

Proton spin-lattice relaxation time in the α-VHx

The ¹H spin-lattice relaxation time T₁ has been measured in the α-VH_x. It is found that T₁ in the α-phase is essential ly determined by contact hyperfine interactions, and its variation with hydrogen concentration is in accord with a rigid-band model.     

Thermal Conductivity Measurement of Gases by the Transient Short-Hot-Wire Method

Measurements of the thermal conductivity of helium and hydrogen are performed using the transient short-hot-wire method. The short hot wire is made of platinum and has a diameter of about 10 μm and a length of about 15 mm. It is attached by spot welding to platinum terminals with a diameter of 1.5 mm. The probe is inserted into the sample vessel that has a volume of 35 cm³ and an inner diameter of 30 mm. The thermal conductivity is evaluated by comparing a numerical solution of the heat conduction in and around the short wire with the experimentally obtained temperature rise of the wire. The measured thermal conductivities show good reproducibility. Also, the measured thermal conductivities agree with the reference equations within a deviation of ± 1%.     

Preparation of PTFE-based fuel cell membranes by combining latent track formation technology with graft polymerization

Swift heavy 56 MeV ¹⁵N³⁺ ions were generated with particle fluences of 0, 3×10⁶, 3×10⁷, 3×10⁸, 3×10⁹ ions/cm² to form a latent track zone in a 25-μm-thick film of polytetrafluoroethylene (iPTFE). Styrene (St) was then grafted onto the iPTFE films by UV-irradiation or pre-γ-irradiation, and after sulfonation iPTFE-based proton-conducting membranes were obtained, here called, iPTFE-g(UV)-PStSA and iPTFE-g(γ)-PStSA membranes, respectively, which had a straight cylindrical damage zone around the ion path. The degree of grafting was found to be about 7.5% with a particle fluence of 3×10⁷ ions/cm² and with either the UV-method or the γ-method. The ion-exchange capacity, proton conductivity in the thickness direction, MeOH permeability, tensile strength and elongation at break of the obtained iPTFE-g(UV)-PStSA membrane were 0.50 mmol/g, 0.06 S/cm, 0.15×10⁻⁶ cm²/s, 50 MPa and 600%, in contrast to 0.06 mmol/g, 0.06 S/cm, 0.35×10⁻⁶ cm²/s, 19 MPa and 210% for the iPTFE-g(γ)-PStSA membrane, respectively. In comparison, the Nafion 112 measured in our laboratory exhibited an ion-exchange capacity of 0.91 mmol/g, a proton conductivity of 0.06 S/cm, a MeOH permeability of 1.02×10⁻⁶ cm²/s, a tensile strength of 35 MPa and an elongation at break of 295%. It can be concluded from these data that the lower crossover of MeOH, the same proton conductibility, the lower ion-exchange capacity, and the superior mechanical properties of the UV-grafted proton-conducting membranes compared to the Nafion make them promising materials for widespread application in direct methanol fuel cells. On the other hand, the tests of mechanical strength showed that the PTFE base film is subject to degradation by the ion-beam irradiation as well as the γ-irradiation.     

Efficient and Practical Arene Hydrogenation by Heterogeneous Catalysts under Mild Conditions

An efficient and practical arene hydrogenation procedure based on the use of heterogeneous platinum group catalysts has been developed. Rh/C is the most effective catalyst for the hydrogenation of the aromatic ring, which can be conducted in iPrOH under neutral conditions and at ordinary to medium H₂ pressures (<10 atm). A variety of arenes such as alkylbenzenes, benzoic acids, pyridines, furans, are hydrogenated to the corresponding cyclohexyl and heterocyclic compounds in good to excellent yields. The use of Ru/C, less expensive than Rh/C, affords an effective and practical method for the hydrogenation of arenes including phenols. Both catalysts can be reused several times after simple filtration without any significant loss of catalytic activity.     

A method for ion-exchange separation of low levels of americium in environmental materials

A method is presented for separating low levels of americium from large environmental samples ( $ 200 l. of sea-water, $ 100 g of sediment, 500 g of biological material, etc.) by applying an anion-exchange process in methanolic acid medium.