Glutathione peroxidase, a selenium-containing enzyme, is believed to protect cells from the toxicity of hydroperoxides. The physiological role of this enzyme has previously been implicated mainly using animals fed with a selenium-deficient diet. Although selenium deficiency also affects the activity of several other cellular selenium-containing enzymes, a dramatic decrease of glutathione peroxidase activity has been postulated to play a role in the pathogenesis of a number of diseases, particularly those whose progression is associated with an overproduction of reactive oxygen species, found in selenium-deficient animals. To further clarify the physiological relevance of this enzyme, a model of mice deficient in cellular glutathione peroxidase (GSHPx-1), the major isoform of glutathione peroxidase ubiquitously expressed in all types of cells, was generated by gene-targeting technology. Mice deficient in this enzyme were apparently healthy and fertile and showed no increased sensitivity to hyperoxia. Their tissues exhibited neither a retarded rate in consuming extracellular hydrogen peroxide nor an increased content of protein carbonyl groups and lipid peroxidation compared with those of wild-type mice. However, platelets from GSHPx-1-deficient mice incubated with arachidonic acid generated less 12-hydroxyeicosatetraenoic acid and more polar products relative to control platelets at a higher concentration of arachidonic acid, presumably reflecting a decreased ability to reduce the 12-hydroperoxyeicosatetraenoic acid intermediate. These results suggest that the contribution of GSHPx-1 to the cellular antioxidant mechanism under normal animal development and physiological conditions and to the pulmonary defense against hyperoxic insult is very limited. Nevertheless, the potential antioxidant role of this enzyme in protecting cells and animals against the pathogenic effect of reactive oxygen species in other disorders remains to be defined. The knockout mouse model described in this report will also provide a new tool for future study to distinguish the physiological role of this enzyme from other selenium-containing proteins in mammals under normal and disease states.

Incorporation reactions of carbon dioxide (CO(2)) with N-Boc-α-amido and α-acetoxy stannanes were developed using CsF as a mild tin activator. Monoprotected α-amido stannanes could be used, and the corresponding arylglycine derivatives were obtained in moderate-to-high yields under 1 MPa (10 atm) of CO(2) pressure. α-Acetoxy stannanes also underwent carboxylation to afford mandelic acid derivatives in excellent yields under ambient CO(2) pressure. Both transformations enabled the synthesis of α-tertiary and α-quaternary carboxylic acid derivatives. In addition, the chirality of (S)-N-tert-butylsulfonyl-α-amido stannanes was transferred with up to 90% inversion of configuration at 100 °C.

A catalytic enantioselective silylation of N-tert-butylsulfonylimines using a Cu-secondary diamine complex was demonstrated. The resulting optically active α-amino silanes could be carboxylated under a CO2 atmosphere (1 atm) to afford the corresponding α-amino acids in a stereoretentive manner. This two-step sequence provides a new synthetic protocol for optically active α-amino acids from gaseous CO2 and imines in the presence of a catalytic amount of a chiral source.

It′s a gas: A novel one‐pot process for the synthesis of α‐amino acids from imine equivalents using CO2 gas as a carbon source has been developed. This reaction was made possible by the reagent combination of TMSSnBu3 and CsF (see scheme). Three successive reactions (imine formation, stannylation, and carboxylation) proceeded in the same flask under these conditions to give products in up to 79 % yield. Boc=tert‐butoxycarbonyl, TMS=trimethylsilyl.

Oxidative cross-coupling is a powerful synthetic strategy for forming a carbon−carbon bond from two nucleophiles having C−H bonds. However, controlling the coupling selectivity (homovs cross-coupling) and the chemo-(C−C vs C−O) and regioselectivity in the reaction of two distinct enolizable substrates under aerobic conditions is notoriously challenging. Here, we present a regiodivergent oxidative cross-coupling reaction between catechols and carbonyl compounds (2-oxindoles and benzofuranones). The oxidative cross-coupling proceeds at the C(6) position of 4-substituted catechols under catalyst-free conditions, while the Pd(II)-BINAP-μ-hydroxo catalyst promotes the reaction at the C(5) position. A series of mechanistic control experiments support a homolytic aromatic substitution mechanism for the carbon−carbon bond-forming processes in both the C(6)-and C(5)selective coupling reactions. Furthermore, computational analyses suggest that Pd(II)−catecholate is a key catalytic active species, which serves as a SOMO-phile, to facilitate the endothermic C(5)-selective carbon−carbon bond formation and the exothermic aerobic oxidative aromatization.

Objective Using cluster analysis, to identify the subgroup of patients with APS with the poorest prognosis and clarify the characteristics of that subgroup. Methods This is a longitudinal retrospective cohort study of APS patients. Using clinical data and the profile of aPL, cluster analysis was performed to classify the patients into subgroups. Events were defined as thrombosis, severe bleeding, and mortality. Results A total of 168 patients with APS were included. Cluster analysis classified the patients into three subgroups; Cluster A (n = 61): secondary APS, Cluster B (n = 56): accumulation of cardiovascular risks and arterial thrombosis, Cluster C (n = 61): triple positivity of aPL and venous thrombosis. Cluster B showed significantly higher frequency of the events and higher mortality compared with the other clusters (P = 0.0112 for B vs A and P = 0.0471 for B vs C). Conclusion Using cluster analysis, we clarified the characteristics of the APS patients with the poorest prognosis. Risk factors for cardiovascular disease may further increase events in patients with APS.

Cross-coupling reactions using tertiary carboncentered radicals are an important class of transformations for constructing C(sp 3 )À C(sp 3 ) bonds, but the use of dimers as precursors of the persistent radicals is quite rare. Herein, we describe a radical-based cross-coupling reaction between dimers (prepared from 2-oxindoles and benzofuranones) and azo compounds that proceeds simply upon heating the reaction mixture. We present a conformational analysis of the dimers and we characterize the generation of a persistent radical via cleavage of the elongated C(3)À C(3') σ-bond. The behavior of the dimers in solution was characterized by spectroscopic analysis, helping to provide a basis for expanding the substrate scope of the cross-coupling reaction.

The corn hull dietary fiber was decomposed into their components such as cellulose, hemicellulose‐A, ‐B, ‐C, ‐other and lignin by the Siegel method, and their contents were 16%, 1%, 57%, 14% and 2%, respectivity. The components of ordinary corn fiber were insoluble in water, but several decomposed fractions were able to dissolved. The solubility in water of hemicellulose‐B was well and of hemicellulose A was slightly, but other fractions were insoluble. Hemicellulose‐A, ‐B, ‐C and ‐other fractions were made up of about 30% of arabinose and 50% of xylose. Uronic acid contents and solubility in water of each hemicellulose fraction were mutually related.