Analytical application of organic reagents in hydrophobic gel media-IV Selective preconcentration of Cobalt(II) with 1-nitroso-2-naphthol gel

Cobalt is selectively extracted from solution onto gel beads impregnated with 1-nitroso-2-naphthol. A concentration factor of 67 has been achieved by passing 2 litres of sea water containing 0.05 ppm of cobalt over the beads at a flow-rate of 40 ml/hr. The cobalt is eluted from the beads with methyl isobutyl ketone.     

Accurate mass determination by multiple sprayers nano-electrospray mass spectrometry on a magnetic sector instrument

A new technique for accurate mass determination by using multiple sprayers nano-electrospray ionization mass spectrometry (nano-ESI-MS) on a magnetic sector instrument is described. Metal coated glass capillaries were used as nano-ESI sprayers. One of the sprayers was used for the reference compound solution, and others were used for the introduction of sample solutions. The spectra of the different compounds were obtained by shifting each sprayer's position relative to the sampling orifice. The accurate masses of several standard compounds were obtained with good accuracy, without problems arising from differences in ionization efficiency between the sample compounds and reference compound.     

Ethylene hydroformylation over a nafion-supported rhodium catalyst

Ethylene hydroformylation over a Nafion-supported rhodium catalyst has been studied under atmospheric pressure in the temperature range of 100–135 °C, using the transient response method.

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Application of modified Mosher's method for primary alcohols with a methyl group at C2 position

The absolute configurations of a series of primary alcohols possessing a branched methyl group at C2 position were examined on the basis of a modified Mosher's method proposed by Minale et al. It was revealed that in many cases the absolute configurations at C2 were assignable from the chemical shift differences of geminal protons of the methylene attached to the ester linkage in the alpha-methoxy-alpha-trifluoromethylphenylacetyl (MTPA) derivatives. The scope and limitation of this method are described.     

Anionic NaCl-type frameworks of [Mn(II)(HCOO)(3)(-)], templated by alkylammonium, exhibit weak ferromagnetism

We present the synthesis, characterization by IR, TGA, single crystal X-ray structure and magnetic properties of a novel series of NaCl-type frameworks of [AmineH(+)][Mn(HCOO)(3)(-)], templated by alkylammonium. The anionic NaCl-framework of [Mn(HCOO)(3)(-)] is counter-balanced by the alkylammonium cations located in the cavities of the framework to which they are hydrogen-bonded. The divalent manganese ions have octahedral geometry and are bridged by the formate in an anti-anti mode of coordination. All the compounds exhibit long-range antiferromagnetism below 9 K with a slight non-collinear arrangement of the moments. The canting, likely due to second-order spin-orbit coupling, is via a Dzyaloshinski-Moriya antisymmetric exchange mechanism. A spin-flop is observed in each case at fairly low fields. An orthorhombic to monoclinic transformation was observed for the protonated cyclotrimethyleneamine that is accompanied by localization of the cations into two positions below 240 K from the rapid dynamic flipping of the ring observed at room temperature.     

Absolute structure, biosynthesis, and anti-microtubule activity of phomopsidin, isolated from a marine-derived fungus Phomopsis sp.

The absolute configuration of phomopsidin, a marine-derived fungal metabolite from Phomopsis sp. isolated at Pohnpei, was determined by the exciton chirality method as 6S, 7S, 8S, 11S, 12R, and 15R. The biosynthetic study using ¹³C-labeled precursors revealed the origin of all carbon atoms in phomopsidin, which was built by nine acetates and three methyl groups from l-methionine. Inhibitory activities of phomopsidin and its Me ester derivative against microtubule assembly were examined together with the structurally related compounds MK8383, solanapyrones, and tanzawaic acids. Phomopsidin and its (16Z)-isomer (MK8383) showed anti-microtubule activity at IC₅₀ of 5.7 and 8.0 μM, respectively, while the Me ester and other compounds were not active at 100 μM.