Reaction of alpha,alpha-dibromo oxime ethers with Grignard reagents: alkylative annulation providing a pyrimidine core

A convergent synthesis of a pyrimidine core has been achieved. Treatment of alpha,alpha-dibromo oxime ethers, which are easily derived from the corresponding esters, with a variety of Grignard reagents provides trisubstituted pyrimidines in good yields. This new method offers an easy access to functionalized pyrimidines.     

Characterization of Rh-Cr mixed-oxide nanoparticles dispersed on (Ga(1-x)Zn(x))(N(1-x)Ox) as a cocatalyst for visible-light-driven overall water splitting

The structure of Rh-Cr mixed-oxide (Rh(2)(-)(y)Cr(y)O(3)) nanoparticles dispersed on (Ga(1)(-)(x)Zn(x))(N(1)(-)(x)O(x)) is characterized by electron microscopy and X-ray spectroscopy. The Rh(2)(-)(y)Cr(y)O(3) nanoparticle is an efficient cocatalyst for photocatalytic overall water splitting on the (Ga(1)(-)(x)Zn(x))(N(1)(-)(x)O(x)) solid solution and is loaded onto the catalyst by impregnation from an aqueous solution containing Na(3)RhCl(6).2H(2)O and Cr(NO(3))(3).9H(2)O followed by calcination in air. Impregnation of the (Ga(1)(-)(x)Zn(x))(N(1)(-)(x)O(x)) with 1 wt % Rh and 1.5 wt % Cr followed by calcination at 623 K for 1 h provides the highest photocatalytic activity. Structural analyses reveal that the activity of this photocatalyst is strongly dependent on the generation of trivalent Rh-Cr mixed-oxide nanoparticles with optimal composition and distribution.     

On Wess–Zumino gauge

In the relation between the linear (L) supersymmetry (SUSY) representation and the nonlinear (NL) SUSY representation we discuss the role of the Wess–Zumino gauge. We show in two-dimensional spacetime that a spontaneously broken LSUSY theory with mass and Yukawa interaction terms for a minimal off-shell vector supermultiplet is obtained from a general superfield without imposing any special gauge conditions in N=2$N=2$ NL/L SUSY relation.     

O-Cubed Modeling and Simulator for Computational Organization Design

This paper discusses the development of O-cubed (operational organization oriented) modeling and a simulator for computational organization design. O-cubed modeling is used to describe an organization model in terms of models of coordination structures, tasks, and agents. The model of a coordination structure can represent not only task decomposition and allocation, but also choices between hierarchical management and autonomous management. The model of a task can represent the workflow within an organization. Using the O-cubed simulator, we can easily describe the models for coordination structure, tasks and agents, so that agents can make decisions concerning task processing and choose coordination structures effectively. In order to show applicability of the modeling and simulator, we describe an O-Cubed model of cooperation in a kitchen of a restaurant. The cooperation is good example to explain organization design, because it contains balanced elements of coordination structures, tasks, and agents. The example show that the organization models described by O-cubed modeling and the simulator are promising models for designing organizations.     

Cell specific peptide-conjugated polysaccharide nanogels for protein delivery

A cell specific peptide (Arg‐Gly‐Asp; RGD)‐modified nanogel was prepared and evaluated for its potential to act as a protein delivery carrier. A bovine serum albumin (BSA)/RGD‐modified nanogel complex was efficiently internalized into cells through integrin‐mediated endocytosis. Endosomal escape of the RGD‐modified nanogel was observed after 24 h incubation. The nanogel proved useful for targeted protein delivery.

     

A new understanding on how heme metabolism occurs in heme oxygenase: water-assisted oxo mechanism

Heme metabolism by heme oxygenase (HO) is investigated with quantum mechanical/molecular mechanical (QM/MM) calculations. A mechanism assisted by water is proposed: (1) an iron-oxo species and a water molecule are generated by the heterolytic cleavage of the O-O bond of an iron-hydroperoxo species in a similar way to P450-mediated reactions, (2) a hydrogen atom abstraction by the iron-oxo species from the generated water molecule and the C-O bond formation between the water molecule and the α-meso carbon take place simultaneously. The water molecule is hydrogen-bonded to the oxo ligand and to the water cluster in the active site of HO. The water cluster can control the position of the generated water molecule to ensure the regioselective oxidation of heme at the α-meso position, at the same time, can facilitate the oxidation by stabilizing a positive charge on the water molecule in the transition state. A key difference between HO and P450 is observed in the structure of the active site; Thr252 in P450 blocks the access of the water molecule to the α-meso position, and can thus suppress the undesired heme oxidation for P450.     

Formation and High Reactivity of the anti‐Dioxo Form of High‐Spin μ‐Oxodioxodiiron(IV) as the Active Species That Cleaves Strong C−H Bonds

Recently, it was shown that μ‐oxo‐μ‐peroxodiiron(III) is converted to high‐spin μ‐oxodioxodiiron(IV) through O?O bond scission. Herein, the formation and high reactivity of the anti‐dioxo form of high‐spin μ‐oxodioxodiiron(IV) as the active oxidant are demonstrated on the basis of resonance Raman and electronic‐absorption spectral changes, detailed kinetic studies, DFT calculations, activation parameters, kinetic isotope effects (KIE), and catalytic oxidation of alkanes. Decay of μ‐oxodioxodiiron(IV) was greatly accelerated on addition of substrate. The reactivity order of substrates is toluene<ethylbenzene≈cumene<trans‐β‐methylstyrene. The rate constants increased proportionally to the substrate concentration at low substrate concentration. At high substrate concentration, however, the rate constants converge to the same value regardless of the kind of substrate. This is explained by a two‐step mechanism in which anti‐μ‐oxodioxodiiron(IV) is formed by syn‐to‐anti transformation of the syn‐dioxo form and reacts with substrates as the oxidant. The anti‐dioxo form is 620 times more reactive in the C?H bond cleavage of ethylbenzene than the most reactive diiron system reported so far. The KIE for the reaction with toluene/[D₈]toluene is 95 at ?30 °C, which the largest in diiron systems reported so far. The present diiron complex efficiently catalyzes the oxidation of various alkanes with H₂O₂.     

Model calculation for ion mobility in air using the MOBCAL program

We determined new potential parameters for a calculation of ion mobility in air using the MOBCAL program. In our model, we regard air as a virtual uni-atomic molecular gas. And the Lennard-Jones parameters for various kinds of atoms in molecular ions were determined with simple and systematic methods. Using these parameters, we have calculated the mobilities of product ions from chemical warfare agents, normal saturated hydrocarbons, and illicit drugs. Most of the calculation results showed good agreement with the experimental values. Therefore this calculation method will be useful for understanding of the ion mobility spectrometry in air.