No abstract

Primary alcohols undergo oxidative condensation upon treatment with RuH2(PPh3)4 catalyst to give esters and molecular hydrogen. Similarly, 1,4-and 1,5-diols can be converted into the corresponding 7-and -lactones, respectively. The lactonization is greatly enhanced by accepting hydrogen with an appropriate hydrogen acceptor such as acetone. Primary alcohols are oxidized chemoselectively in the presence of secondary alcohols to give

Cationic polymerization of isobutyl vinyl ether (IBVE) was carried out with use of the HC1-IBVE adduct [1: CH3CH(OiBu)Cl]/Lewis acid (MX") initiating systems in CH2CI2 at -15 °C. Living polymers were obtained with 1 in conjunction with weak Lewis acids such as ZnCl2 and SnBr4; in contrast, the 1/MX" initiating systems with strong Lewis acids (SnCl4, TiCl4, and EtAlCl2) gave nonliving polymers. However, on addition of ammonium salts (nBu4N+Y~) and phosphonium salts (nBu4P+Y) carrying nucleophilic anions (Y~= Cl", Br, I", CH3CO2"), well-defined living polymers were indeed obtained (Mw/Mn ~1.1) with the SnCl4-based system. As model reactions of these living and nonliving polymerizations, a series of mixtures of 1 and MX" in the presence and absence of the salts were analyzed in CH2CI2 at -78 °C or above directly by NMR spectroscopy. Upon mixing SnCl4 with 1, the -methine and the pendant methylene absorptions of 1 shifted remarkably downfield (e.g., up to ca. 10 ppm for the former), and the extent of the downfield shifts increased with increasing SnCl4 concentration. On further addition of the salts with nucleophilic anions, the downfield signals returned to the original upfield position for the covalent adduct 1 alone. Thus, l/SnCl4 generates an ionic growing species that is in a rapid equilibrium with the covalent precursor 1, and the salts suppress the ionic dissociation of the growing carbocation to induce living cationic polymerization.

Vancomycin-resistant Enterococcus faecalis (VRE) has become a significant threat in nosocomial settings. Bacteriophage (phage) therapy is frequently proposed as a potential alternative therapy for infections caused by this bacterium. To search for candidate therapeutic phages against Enterococcus faecalis infections, 30 Enterococcus faecalis phages were isolated from the environment. One of these, virulent phage phiEF24C, which has a broad host range, was selected for analysis. The plaque-forming ability of phiEF24C was virtually unaffected by differences in the clinical host strains. Furthermore, the phage had a shorter latent period and a larger burst size than ordinary tailed phages, indicating that phiEF24C has effective lytic activity against many Enterococcus faecalis strains, including VRE. Morphological and genomic analyses revealed that phiEF24C is a large myovirus (classified as family Myoviridae morphotype A1) with a linear double-stranded DNA genome of c. 143 kbp. Analyses of the N-terminal amino acid sequences of the virion proteins, together with the morphology and the genome size, speculated that phiEF24C is closely related to other myoviruses of Gram-positive bacteria that have been used experimentally or practically for therapy or prophylaxis. Considering these results, phiEF24C may be a potential candidate therapeutic phage against Enterococcus faecalis infections.

Multidrug-resistant uropathogenic Escherichia coli (UPEC) is increasing gradually on a worldwide scale. We therefore examined the possibility of bacteriophage (phage) therapy for urinary tract infections (UTIs) caused by the UPEC strains as an alternative to chemotherapy. In addition to the well-known T4 phage, KEP10, which was newly isolated, was used as a therapeutic phage candidate. KEP10 showed a broader bacteriolytic spectrum (67%) for UPEC strains than T4 (14%). Morphological and genetic analyses showed that KEP10 resembles phage T4. Phages T4 and KEP10 injected into the peritoneal cavity of mice were distributed immediately to all organs examined and maintained a high titer for at least 24 h. They were stable in the urine of both mice and humans for 24 h at 37 degrees C. Administration of these phages into the peritoneal cavity caused a marked decrease in the mortality of mice inoculated transurethrally with a UPEC strain, whereas most of the control mice died within a few days of bacterial infection. Inoculation with phage alone produced no adverse effects attributable to the phage per se. The present study experimentally demonstrated the therapeutic potential of phage for E. coli-induced UTIs, and T-even-related phages may be suitable candidates with which to treat them.