exo- and enantioselective cycloaddition of azomethine ylides generated from N-alkylidene glycine esters using chiral phosphine-copper complexes

High diastereo- and enantioselectivities were obtained for the asymmetric 1,3-dipolar cycloaddition of azomethine ylides generated from N-alkylideneglycine esters with dipolarophiles using chiral phosphine-copper complexes as catalysts. Whereas the cycloaddition of azomethine ylides catalyzed by metal salts generally afforded endo-adducts as the predominant product, the present method is the first example of an exo-selective cycloaddition. [reaction: see text]     

Suppressive effect of the SOS-inducing activity of chemical mutagen by citric acid esters from Prunus mume Sieb. Et Zucc. using the Salmonella typhimurium TA1535/pSK1002 umu test

A methanol extract from Prunus mume Sieb. Et Zucc. showed a suppressive effect of the SOS-inducing activity on the mutagen 3-amino-1,4-dimethyl-SH-pyrido[4,3-b]indole(Trp-P-1) in the Salmonella typhimurium TA1535/pSK1002 umu test. The methanol extract was re-extracted with hexane, dichloromethane, ethyl acetate, butanol and water. The dichloromethane and ethyl acetate fractions showed suppressive effect. Suppressive compounds were isolated by silica gel column chromatography and identified as trimethyl citrate (1) and dimethyl citrate (2) by GC-MS, IR and 1H and 13C-NMR spectroscopy. Compounds 1 and 2 suppressed 51 and 39% of the SOS-inducing activity at a concentration of 2.0 micromol/mL.     

A new biomaterial,hen egg shell membrane,to eliminate heavy metal ion from their dilute waste solution

The egg shell membrane (ESM) is an intricate lattice network of stable and water-insoluble fibers with high surface area. ESM accumulates and eliminates various heavy metal ions from dilute aqueous solution with high affinity and in short contact time, depending on pH and characteristics of the individual ion. Under certain conditions, the level of precious ions, Au, Pt, and Pd accumulation approaches 55, 25, and 22% of dry wt of ESM, respectively. Also uranium uptake 30% of that of ESM. Experiments suggested that ESM is promising to use for the purpose of removal/recovery of metals and water pollution control.     

Ultraweak Luminescence Generated by Sweet Potato and Fusarium oxysporum Interactions Associated with a Defense Response

Abstract— Ultraweak luminescence generated by sweet potato and nonpathogenic Fusarium oxysporum interactions associated with a defense response was detected by a photoncounting method using ultrahigh-sensitive photodetectors. The time-dependent intensity variation, the spectrum and the two-dimensional imaging of the ultraweak luminescence are indicative of the defense response of the sweet potato to F. oxysporum. The production of ipomeamarone as a phytoalexin means that F. oxysporum induced the defense response in the sweet potato.     

Two-color double resonance in the four-photon ionization of nitric oxide

We have measured the two-color double resonance enhanced four-photon ionization and the fluorescence de-enhanced spectra of nitric oxide by using two tunable pulsed dye lasers. The spectra show clear structure in the third-photon (8.2 eV) region. Also discussed is the multiphoton ionization mechanism in the resonance state.     

Lifetime of living polymers in cationic polymerization. II. Living polymerization of isobutyl vinyl ether initiated by the hydrogen iodide/zinc halide systems

In the living cationic polymerization of isobutyl vinyl ether (IBVE) initiated by the hydrogen iodide/zinc halide (HI/ZnX₂; X = I, Br, Cl) systems, the concentration ([P^*]) of the living propagating species was determined by quenching with sodiomalonic ester ( 1 ). The quenching reaction was shown to be clean, instantaneous, and quantitative to give poly (IBVE) with a terminal malonate group from which [P^*] was obtained by ¹H-NMR spectroscopy. In the polymerizations in toluene below +25°C, [P^*] was constant and equal to the initial concentration ([HI]₀) of hydrogen iodide, independent of the type and concentrations of ZnX₂ as well as monomer conversion. At 0 and +25°C, however, the living species started decaying immediately after the complete consumption of monomer. In contrast, such a decay process was absent at ?15°C even in the absence of monomer until about an hour (depending on the conditions) after the end of polymerization. The deactivation reaction was first order in [P^*], and the lifetime (half-life) of the living species was longer at lower temperature and at lower ZnX₂ concentration. On the basis of these [P^*] and lifetime measurements, the HI/ZnX₂ systems were also compared with the HI/I₂ counterpart.     

PI Mtoyoura: a new PI M subtype found by separator and hybrid isoelectric focusing

In the course of a population study of alpha 1-antitrypsin polymorphism by separator isoelectric focusing, a variant phenotype having a somewhat narrower spacing than PI M1M3 was observed in a Japanese blood donor. Family studies by hybrid isoelectric focusing in a carrier ampholyte-supplemented immobilized pH gradient from 4.35-4.65 revealed that the products of the responsible gene, PI*Mtoyoura, were extremely close but slightly cathodal to those of PI*M1. The difference in isoelectric point between them corresponded to the resolving limit of isoelectric focusing. For this reason, although the propositus' father was deduced to have the genotype PI*M1/PI*Mtoyoura, the products of these two genes failed to form a double band pattern. Thus, the gene frequency for PI*Mtoyoura was unknown. These findings, however, indicate that a further microheterogeneity in the PI M subtype exists at least in the Japanese.     

New guanosine derivatives: facile O6-phosphorylation,thiophosphinylation sulfonylation and silylation of guanosine derivatives by 4-dimethylaminopyridine catalized reaction

Appropriately protected guanosine derivatives were successfully converted to the corresponding O⁶-substituted guanosine derivatives by treatment with dialkyl- or diaryl-phosphoryl halides, dialkyl- or diaryl-phosphinothioyl halides, arenesulfonyl chlorides, and trialkylsilyl chlorides.