Selective reduction of thioacetal to sulfide by gallium(II) chloride

The reaction of dithioacetals with gallium(II) chloride followed by the acid treatment afforded sulfides in good yields.     

Antibacterial activity of two chalcones, xanthoangelol and 4-hydroxyderricin, isolated from the root of Angelica keiskei KOIDZUMI

Two chalcones, xanthoangelol (I) and 4-hydroxyderricin (II), isolated from the root of Angelica keiskei KOIDZUMI (Umbelliferae) showed antibacterial activity against gram-positive pathogenic bacteria. The activity of I on Micrococcus luteus IFO-12708 (minimum inhibitory concentration (MIC), 0.76 microgram/ml) was the same potency as that of gentamicin, which is used as a standard. Although the activity of both chalcones on plant-pathogenic bacteria was lower than that of streptomycin sulfate, used as a positive control, they also exhibited growth-inhibitory effects. The antibacterial activity of I isolated from Angelica keiskei KOIDZUMI is being reported here for the first time. The growth-inhibitory effect of II on plant-pathogenic bacteria is also reported for the first time in this paper.     

Isolation of cytotoxic substance, kalafungin from an alkalophilic actinomycete, Nocardiopsis dassonvillei subsp. prasina

An alkalophilic actinomycete, strain OPC-553 regarded as Nocardiopsis dassonvillei subsp. prasina, produced the cytotoxic substance, TS-1, which showed a marked inhibitory activity against L5178Y mouse leukemic cell in vitro. The cytotoxicity of TS-1 on this cell was very strong and its ID50 was 0.018 micrograms/ml. Through direct comparison of its spectral data with those of an authentic sample, TS-1 was identified as the antifungal antibiotic, kalafungin, already isolated from the culture broth of Streptomyces tanashiensis. However, the isolation of kalafungin from an alkalophilic actinomycete and its cytotoxicity are reported for the first time in this paper.     

Lewis acid-catalyzed reduction of dithioacetals by 1,4-cyclohexadiene

Dithioacetals were reduced by 1,4-cyclohexadiene in the presence of a catalytic amount of Lewis acid to afford the corresponding sulfides in good yields.     

Photoinduced intramolecular electron-transfer processes in [60]fullerene and N,N-Bis(biphenyl)aniline molecular systems in solutions

Photoinduced intramolecular charge-separation and charge-recombination processes in covalently connected C(60)-(spacer)-bis(biphenyl)aniline (C(60)-sp-BBA) and C(60)-((spacer)-bis(biphenyl)aniline)(2) (C(60)-(sp-BBA)(2)) have been studied by time-resolved fluorescence and transient absorption methods. Since a flexible alkylthioacetoamide chain was employed as the spacer, the folded structures in which the BBA moiety approaches the C(60) moiety were obtained as optimized structures by molecular orbital calculations. The observed low fluorescence intensity and the short fluorescence lifetime of the C(60) moiety of these molecular systems indicated that charge separation takes place via the excited singlet state of the C(60) moiety in a quite fast rate and high efficiency even in the nonpolar solvent toluene, which was a quite new observation compared with reported dyads with different spacers. From the absorption bands at 880 and 1000 nm in the nanosecond transient absorption spectra, generations of C(60)(.-)-sp-BBA(.+) and C(60)(.-)-(sp-BBA(.+))(sp-BBA) were confirmed. The rates of charge separation and charge recombination for C(60)-(sp-BBA)(2) are faster than those for C(60)-sp-BBA, suggesting that one of the BBA moieties approaches the C(60) moiety by pushing another BBA moiety because of the flexible spacers.     

Direct detection of a phase change in PdO/CeO2 supported on chi-Al2O3 by means of in situ high-temperature measurements of XRD and FTIR.

Phase changes between PdO and Pd metal can be directly detected in PdO/CeO2 catalysts supported on chi-Al2O3 by means of in situ high-temperature measurements of X-ray diffraction and FT-IR in relation to the catalytic activity for the methane oxidation of microcrystalline PdO. Reversible changes in the solid phases are observed from PdO to Pd and Pd to PdO under O2-deficient and O2-excess atmospheres, respectively. Nanosizes of PdO and Pd crystallites, the distorted PdO crystal structure along the (110) plane, and also a distorted Pd metal crystal structure along the (200) plane as well as the large surface area elucidate the high catalytic activity for the methane oxidation of PdO/CeO2 catalysts prepared with an atomic ratio of Pd:Ce = 1:1.