Viscous Shock Wave and Boundary Layer Solution to an Inflow Problem for Compressible Viscous Gas

The inflow problem for a one-dimensional compressible viscous gas on the half line (0,+) is investigated. The asymptotic stability on both the viscous shock wave and a superposition of the viscous shock wave and the boundary layer solution is established under some smallness conditions. The proofs are given by an elementary energy method.     

Synthesis of chiral oxime ethers based on regio- and enantioselective allylic substitution catalyzed by iridium-pybox complex

The oxygen atom of oximes acts as a reactive nucleophile in the iridium-catalyzed allylic substitution of unsymmetrical substrates to give the branched oxime ethers. Among several chiral ligands evaluated, the iridium complex of pybox ligand having phenyl group catalyzed the allylic substitution of phosphates with high activity to form the branched oxime ethers with good enantioselectivities.     

A highly stereocontrolled total synthesis of dysiherbaine

A total synthesis of dysiherbaine, a potent agonist of AMPA-KA type glutamate receptors, has been accomplished in completely stereocontrolled manner starting from tri-O-acetyl-D-galactal in 25 steps and in 3% overall yield.     

Microwave spectrum of CH3OD

The microwave spectrum of CH₃OD has been observed in the frequency region between 14 and 92 GHz. All the ground-state transitions with J ≤ 8 and J = 2 ← 1, a-type transitions in the excited torsional states (v = 1 and v = 2) have been observed. The spectrum has been analyzed and rotational constants, torsional constants, torsion-vibration-rotation interaction constants, and centrifugal distortion constants have been evaluated. The Stark effect measurements have been made and the dipole moment components have been determined as μ_a = 0.833 ± 0.008 D and μ_b = 1.488 ± 0.015 D.     

Scalable Total Syntheses and Structure–Activity Relationships of Haouamines A,B, and Their Derivatives as Stable Formate Salts

Haouamines A, B, and their derivatives were synthesized via Suzuki–Miyaura coupling and three key cyclization reactions as follows: the newly developed palladium(0)-catalyzed arylative cyclization of phenylalanine-derived alkyne–aldehydes with 2-bromoarylboronic acid (an “anti-Wacker”-type cyclization); BF₃ ⋅ OEt₂-promoted Friedel–Crafts-type cyclization of symmetrical electron-rich aromatic rings adjacent to a tertiary allylic alcohol leading to the indeno-tetrahydropyridine skeleton; and (cyanomethyl)trimethylphosphonium iodide-mediated macrocyclization of amino alcohols to afford aza-paracyclophane precursors. The palladium-catalyzed reduction of mono- and di-triflate intermediates in the later stages enabled the alteration of both the position and number of hydroxyl groups on the C-ring. The instability of haouamine B was dramatically improved by salt formation with formic acid. An unambiguous evaluation of the cytotoxicity of the prepared haouamine derivative formates with and without hydroxyl groups at different positions on the C-ring indicated that the catechol structure in haouamine B produced weak cytotoxicity.     

A CO Adsorption Site Change Induced by Copper Substitution in a Ruthenium Catalyst for Enhanced CO Oxidation Activity

Ru is an important catalyst in many types of reactions. Specifically, Ru is well known as the best monometallic catalyst for oxidation of carbon monoxide (CO) and has been practically used in residential fuel cell systems. However, Ru is a minor metal, and the supply risk often causes violent fluctuations in the price of Ru. Performance‐improved and cost‐reduced solid‐solution alloy nanoparticles of the Cu‐Ru system for CO oxidation are now presented. Over the whole composition range, all of the Cu_xRu_1?x nanoparticles exhibit significantly enhanced CO oxidation activities, even at 70 at % of inexpensive Cu, compared to Ru nanoparticles. Only 5 at % replacement of Ru with Cu provided much better CO oxidation activity, and the maximum activity was achieved by 20 at % replacement of Ru by Cu. The origin of the high catalytic performance was found as CO site change by Cu substitution, which was investigated using in situ Fourier transform infrared spectra and theoretical calculations.     

Reaction of α-chloroketones with 1,4-dianion of acetophenone n-ethoxy-carbonylhydrazone

1,4-Dianion of acetophenone N-ethoxycarbonylhydrazone (2) reacts with α-chloroketones such as phenacyl chloride, 1-chloroacetone, 3-chloro-2-butanone, and 1,3-dichloroacetone to give pyrazoline derivatives in good yields. In the reactions of 2-chlorocyclohexanone and 3-chloro-2-norbornanone with 2, cis-chlorohydrin and exo-chlorohydrin were selectively obtained, respectively.     

Stereocontrolled glycosidations using a heterogeneous solid acid, sulfated zirconia, for the direct syntheses of α- and β-manno- and 2-deoxyglucopyranosides

Novel α- and β-stereocontrolled glycosidations using a heterogeneous solid acid, sulfated zirconia (SO₄/ZrO₂), as an activator have been developed. The glycosidations of manno- and 2-deoxyglucopyranosyl α-fluorides with several alcohols using SO₄/ZrO₂ in MeCN proceeded α-stereoselectively, while those with the same activator in the presence of MS 5A in Et₂O occurred with β-stereoselectivity. Thus, both the α- and β-manno- and 2-deoxyglucopyranosides were effectively obtained by the present glycosidations.