Exfoliated nanosheets as a new strong solid acid catalyst

Two-dimensional metal oxide sheets in HTiNbO(5) and HSr(2)Nb(3)O(10), cation-exchangeable layered metal oxides, were examined as solid acid catalysts. Exfoliation of HTiNbO(5) and HSr(2)Nb(3)O(10) in aqueous solutions formed colloidal single-crystal TiNbO(5)(-) and Sr(2)Nb(3)O(10)(-) nanosheets, which precipitated under an acidic condition to form aggregates of HTiNbO(5) nanosheets and HSr(2)Nb(3)O(10) nanosheets. Although esterification of acetic acid, cracking of cumene, and dehydration of 2-propanol were not catalyzed by original HTiNbO(5) because of the narrow interlayer distance, which prevents the insertion of organic molecules, HTiNbO(5) nanosheets functioned as a strong solid acid catalyst for the reactions. Nanosheets of HSr(2)Nb(3)O(10) exhibited no or slight catalytic activity for these reactions. NH(3) temperature-programmed desorption and (1)H magic-angle spinning nuclear magnetic resonance spectroscopy revealed that HTiNbO(5) nanosheets have strong Br?nsted acid sites, whereas HSr(2)Nb(3)O(10) nanosheets do not.     

Preparation of highly potent and selective non-peptide antagonists of the arginine vasopressin V1A receptor by introduction of a 2-ethyl-1H-1-imidazolyl group

To find a new series of arginine vasopressin (AVP) V1A receptor antagonists, the influence of the 2-phenyl group of 2-phenyl-4'-[(2,3,4,5-tetrahydro-1H-1-benzazepin-1-yl)carbonyl]benzanilide (7) was investigated. Replacement of the 2-phenyl group by a 2-ethyl-1H-imidazol-1-yl group was effective in yielding a V1A-selective compound. Moreover, this imidazolyl group was introduced in the same position in YM-35471 (6), and further studies of these compounds were performed. Consequently, we found that the (Z)-4'-({4,4-difluoro-5-[(N-cyclopropylcarbamoyl)methylene]-2,3,4,5-tetrahydro-1H-1-benzazepin-1-yl}carbonyl)-2-(2-ethyl-1H-1-imidazol-1-yl)benzanilide (9f) exhibited highly potent affinity and selectivity, and was the most potent antagonist for the V1A receptor among our compounds. The synthesis and pharmacological evaluation of these compounds are described in this paper.     

Synthesis of the new furo[3,2-h]isoquinoline alkaloid, TMC-120B from Aspergillus ustus

A total synthesis of a new furo[3,2-h]isoquinoline alkaloid TMC120-B (2), isolated from Aspergillus ustus together with two related compounds, has been completed in sixteen steps. The key step is the synthesis of the appropriate 3,7,8-trisubstituted isoquinoline framework (23) based on a thermal electrocyclic reaction of the 1-aza 6pi-electron system involving the benzene double bond. In addition, the microwave assisted electrocyclic reaction of this system was newly performed.     

Tetrabutylammonium phosphomolybdate on fluorapatite: an efficient solid catalyst for solvent-free selective oxidation of sulfides

A new synthetic method of sulfoxides and sulfones using solvent-free oxidations of sulfides with urea–hydrogen peroxide complex (urea–H₂O₂) and tetrabutylammonium phosphomolybdate catalyst on fluorapatite ((Bu₄N)₃[PMo₁₂O₄₀]/FAp). In the solid-phase system the oxidations of aromatic and alkyl sulfides proceeded at 4–25 °C and the corresponding sulfoxides or sulfones were selectively obtained in good yields by controlling the amount of urea–H₂O₂.     

HPLC retention behavior of poly-aromatic-hydrocarbons on aminopropyl silica gels modified with Cu(II)- and Ni(II)-phthalocyanine derivatives in non-polar eluent

A comparative study was conducted to elucidate the mechanism underlying the separation of poly-aromatic-hydrocarbons (PAHs) and related compounds thereof on a column packed with silica gels modified with Ni(II)- or Cu(II)-phthalocyanine derivatives (PCS) (Ni- or Cu-PCS(D) column) and commercially available PYE and NPE columns with a non-polar eluent, such as n-hexane. It has been revealed that the dominant interaction responsible to the separation of PAHs on the Cu-PCS(D) and the PYE columns with n-hexane is the pi-pi interaction; however, in the separation of PAHs having 4 rings such as pyrene on the Ni-PCS(D) column, participation of pi-d interaction was indicated. The predominant role of pi-pi interaction in the separation of PAHs of less than three rings on the Ni-PCS(D) column was demonstrated using anthracene. All the columns possessed planar recognition ability and were estimated to be potentially useful in the separation and the analysis of PAHs.     

Thermoanalytical investigation of the guest-release process in aromatic-guest clathrates of three-dimensional metal complex hosts

The guest-release process was investigated in terms of the activation energy evaluated by thermogravimetry for the en-Td-type clathratescatena--[catena--(ethylenediamine)cadmium(II) tetra--cyanocadmate(II) or -mercurate(II)]-benzene(1/2), -benzene-d ₆(1/2), and -pyrrole(1/2), the Hofmannen-type clathratescatena-[catena--(ethylenediamine)cadmium(II) tetra--cyanonickelate(Il)]-benzene (1/2) and -pyrrole(1/2), the Hofmann-pn-type clathratecatena-[catena--(dl- orl-propylenediamine (cadmium(II) tetra--cyanonickelate(II)]-pyrrole(2/3), and the pn-Td-type clathratescatena-[catena--(dl-propylenediamine) or -(l-propylenediamine)cadmium(II) tetra--cyanocadmate(II)]-benzene(2/3). Values of the activation energy are correlated with the structural change in the metal complex host accompanied by the release of the guest molecules. The crystal structure ofcatena-[ethylenediaminecadmium tetra--cyanonickelate(II)], the residual host of the Hofmann-en-type, has been analyzed to elucidate the correlation.     

Extraction of boron from GSJ rock reference samples and determination of their boron isotopic ratios

The extraction of boron from rocks by methyl borate distillation after alkali fushion was studied. Reproducible extraction was obtained when the ratio of the amounts of flux and rock was ?5:1. Isotope dilution experiments showed there was no appreciable boron isotope fractionation during the extraction under these conditions. ¹¹B/¹⁰B ratios for three standard rocks were 4.044–4.047.     

structural elucidation of novel phosphocholine-containing glycosylinositol-phosphoceramides in filamentus fungi: (2). Spectral analysis of the sugar-inositol portion by 2D-NMR

The sugar-inositol portion of the novel glycosylinositol-phosphoceramides, ZGL1 and ZGL2, from the filamentus fungi, Acremonium sp., were elucidated by a combination of NMR techniques including (1)H-(1)H (COSY and HOHAHA) and (1)H-(13)C (HMQC and HMBC) spectroscopy. Further, examination of the (1)H-(31)P HMQC spectrum showed connectivity of inositol and ceramide through phosphate.     

Determination of the lanthanoids in a neutral hot spring water by neutron activation analysis

Determination of the lanthanoids in a neutral hot spring water has been studied by menas of neutron activation analysis. The aluminium coprecipitation process, which used aluminium as the collector of the lanthanoids, was incorporated in the preparation of a sample for irradiation. Nine lanthanoids, La, Ce, Nd, Sm, Eu, Tb, Tm, Yb and Lu, were determined at ppt levels with satisfactory precision, indicating the effectiveness of aluminium coprecipitation.     

Topical application of a novel, water-soluble gamma-tocopherol derivative prevents UV-induced skin damage in mice

We investigated whether the topical application of a novel, water-soluble gamma-tocopherol (gamma-Toc) derivative, gamma-tocopherol-N,N-dimethylglycinate hydrochloride (gamma-TDMG), could protect against UV-induced skin damage in hairless mice. Topical pre- or post-application of a 5% (93 mM) gamma-TDMG solution in water/propylene glycol/ethanol (2:1:2) significantly prevented sunburn cell formation, lipid peroxidation and edema/inflammation that were induced by exposure to a single dose of UV irradiation of 5 kJ/m2 (290-380 nm, maximum 312 nm). This effect was greater than that seen with two alpha-Toc derivatives, alpha-tocopherol acetate (alpha-TA) and alpha-tocopherol-N,N-dimethylglycinate (alpha-TDMG). When a 5% solution of gamma-TDMG was applied to mouse skin for 1 h, cutaneous gamma-Toc increased by 25-fold after 24 h; levels of cutaneous alpha-Toc increased by only two- and eight-fold in alpha-TDMG and alpha-TA treated skins, respectively. These findings indicated that gamma-TDMG immediately converted to gamma-Toc in the skin and suggest that ability of gamma-TDMG to protect the skin from the damaging effects of irradiation was due to its conversion to gamma-Toc. When a 5% solution of gamma-Toc was applied to mouse skin for 1 h, cutaneous gamma-Toc rapidly increased by 25-fold, but fell to baseline levels by 24 h. In contrast, the concentration of gamma-Toc in skin that was treated with gamma-TDMG similarly increased, but these high levels were maintained after 24 h. These results suggest that gamma-TDMG may be a more effective source of gamma-Toc in skin. Thus, the topical application of gamma-TDMG may be efficacious for the prevention of UV-B-induced skin damage.