Intermolecular [2+2+1] Carbonylative Cycloaddition of Aldehydes with Alkynes,and Subsequent Oxidation to γ‐Hydroxybutenolides by a Supported Ruthenium Catalyst

Intermolecular [2+2+1] carbonylative cycloaddition of aldehydes with alkynes and subsequent oxidation to γ‐hydroxybutenolides is achieved using a supported ruthenium catalyst. A ceria‐supported ruthenium catalyst promotes the reaction efficiently, even with an ambient pressure of CO or without external CO, thus giving the corresponding γ‐hydroxybutenolide derivatives in good to high yields. Moreover this catalyst can be reused with no loss of activity.     

The Reaction of Trialkylboranes with Allyl Phenyl Ether. Syntheses of 1-Alkenes and 1,5-Alkadienes

In the organoborane chemistry, the homologation reaction is one of the useful methods for the synthesis of organoboranes not available via hydroboration.¹⁾ The allylic boranes are known to be highly reactive and exhibit specific behaviors,²⁾ but with few exceptions,³) these are difficult to be prepared directly by the hydroboration reaction.⁵⁾ Previously, we reported that in the reaction of the dianion of phenoxyacetic acid with organoborane, the phenoxy group acts as a good leaving group.⁶⁾ This result suggested us a new homologation reaction converting a saturated organoborane to a allylic borane (1) by the treatment with the carbanion of allyl phenyl ether. Here we wish to report the synthesis of 1-alkenes (II) three-carbon-homologated from starting alkenes⁷⁾ and the regioselective synthesis of 1,5-dienes (III) using allylic borane intermediates (1) (eq. 1).     

Hydroxamic Acid‐Piperidine Conjugate is an Activated Catalyst for Lysine Acetylation under Physiological Conditions

Lysine acylation of proteins is an essential chemical reaction for posttranslational modification and as a means of protein modification in various applications. N,N‐Dimethyl‐4‐aminopyridine (DMAP) derivatives are widely‐used catalysts for lysine acylation of proteins; however, the DMAP moiety mostly exists in a protonated, and thus deactivated, form under physiological conditions due to its basicity. An alternative catalytic motif furnishing higher acylation activity would further broaden the possible applications of chemical lysine acylation. We herein report that the hydroxamic acid‐piperidine conjugate Ph‐HXA is a more active catalytic motif for lysine acetylation than DMAP under physiological conditions. In contrast to DMAP, the hydroxamic acid moiety is mostly deprotonated under aqueous neutral pH, resulting in a higher concentration of the activated form. The Ph‐HXA catalyst is also more tolerant of deactivation by a high concentration of glutathione than DMAP. Therefore, Ph‐HXA might be a suitable catalytic motif for target protein‐selective and site‐selective acetylation in cells.     

Active species transfer-type artificial light harvesting system in the nanosheet – Dye complexes: Utilization of longer wavelength region of sunlight

A novel light harvesting system that captures long-wavelength light of sunlight by the use of hole transfer was newly investigated. Ga phthalocyanine(Ga^IIITMAPc⁴⁺(D)) and Ru porphyrin(Ru^IIDMPyMP²⁺(A)) co-adsorbed reaction system on the synthetic nanosheet was examined as an artificial light harvesting system. By irradiating 660?nm light, where Ga^IIITMAPc⁴⁺(D) absorbs, to the system under a presence of PtCl₆^2? as an electron acceptor, cation radical of Ru^IIDMPyMP²⁺(A) was produced despite that Ru porphyrin adsorbs only 413 and 533?nm light. The efficient hole transfer reaction from Ga^IIITMAPc⁴⁺(D)⁺, that is generated from its excited state, to Ru^IIDMPyMP²⁺(A) takes place on the nanosheet.     

Evolution of dislocation patterns in a tricrystal model subjected to cyclic loading

When a polycrystalline aggregate is deformed beyond the elastic range, dislocations pile up at grain boundaries and make some patterned structures within the grains. If the external load is reversed, most dislocations at grain boundaries and in the patterned structure are supposed to disappear or change their arrangements, but the details are not yet well known. In this study, we examined such changes in dislocation structures by a crystal plasticity analysis. Models for the polycrystalline aggregates consist of three grains and the generation and degeneration of the geometrically necessary dislocations during cyclic loading are examined in detail. The results show that there are some groups of dislocations that do not dissipate but evolve upon reverse loading.     

Nitride‐based hetero‐field‐effect‐transistor‐type photosensors with extremely high photosensitivity

AlGaN/GaN hetero‐field‐effect‐transistor‐type (HFET‐type) photosensors are fabricated with a p‐GaInN optical gate for the detection of visible light. These photosensors employ a two‐dimensional electron gas at the heterointerface between AlGaN and GaN as a highly conductive channel with a high electron mobility. By changing the InN molar fraction in the p‐GaInN optical gate, the wavelength range of the photosensitivity of the HFET‐type photosensors can be controlled. The photosensitivity of the AlGaN/GaN HFET‐type photosensors with a p‐GaInN optical gate greatly surpassed those of commercially available Si pin and Si avalanche photodiodes, and was comparable to those of photomultiplier tubes. (© 2013 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

From Nosé–Hoover chain to Nosé–Hoover network: design of non-Hamiltonian equations of motion for molecular-dynamics with multiple thermostats

A systematic algorithm to design multiple thermostat systems in the framework of the Nosé–Hoover type non-Hamiltonian formulation is presented. Using ‘non uniform’ time transformations in a generalised Hamiltonian equation, we develop the non-Hamiltonian equations of motion for multiple thermostat systems having an arbitrary number of thermostats and arbitrary connections between a physical system and thermostats (‘Nosé–Hoover network’). We then present the algorithm to construct the Nosé–Hoover network equations based on a simple diagram only. On the basis of this algorithm, recursively attached Nosé–Hoover thermostats are introduced as an example of the Nosé–Hoover network and its high efficiency in sampling the canonical distribution for an one-dimensional double-well system is illustrated by numerical calculations.     

The M/G/1 FIFO Queue with Several Customer Classes

In this note we present short derivations of the joint queue length distribution in the M/G/1 queue with several classes of customers and FIFO service discipline.