InBr3-catalyzed reduction of ketones with a hydrosilane: deoxygenation of aromatic ketones and selective synthesis of secondary alcohols and symmetrical ethers from aliphatic ketones

An InBr₃-Et₃SiH reducing system was developed to selectively convert aliphatic ketones to a variety of secondary alcohols in moderate to good yields. An initial mixing of InBr₃ and PhSiH₃ was followed by the addition of aliphatic ketones and a solvent to afford the symmetrical ether derivatives.     

Simple Synthesis of a Heterocyclophane Exhibiting Anti-c-Met Activity by Acting as a Hatch Blocking Access to the Active Site**

A simple approach to the synthesis of heterocyclophane consisting of two 4,4’-bithiazoles has been developed in mild conditions. The heterocyclophane with two short chains was conveniently prepared by Hantzsch thiazoles synthesis using the reaction of 3-tert-butoxycarbonyl-3-azapentanethiocarboxamide with 1,4-dibromobutane-2,3-dione in methanol under reflux for only 15 min. Amino groups at the linkers of this heterocyclophane can be functionalized to give acylated and carbamate derivatives. Their properties as protein kinase inhibitors were investigated, and one of the heterocyclophanes exhibited specific anti-activity for c-mesenchymal epithelial transition factor (IC₅₀=603 nm ), among seven types of protein kinases investigated. The computational site identification by ligand competitive saturation method was used to determine why the one heterocyclophane exhibited strong anti-activity for c-mesenchymal epithelial transition factor.     

Oscillations of nonlinear hyperbolic equations with functional arguments via Riccati method

This paper is devoted to the study of the oscillatory behavior of solutions of nonlinear hyperbolic equations with functional arguments by using integral averaging method and a generalized Riccati technique. First, we establish oscillation results for nonlinear hyperbolic equations by applying oscillation criteria for Riccati inequality. Secondly, we present interval oscillation results for nonlinear hyperbolic equations. These results improve and extend oscillation results of Cui and Xu [1].     

Low-frequency and high-frequency relaxations in dynamic electric birefringence of poly(γ-benzyl-L-glutamate) in m-cresol

The dc component Δn of the electric birefringence of poly(γ-benzyl-L -glutamate) in m-cresol is measured under an ac electric field at frequencies from 0.5 Hz to 200 kHz for solutions covering the dilute and semidilute regions. The dispersion curve indicates that at low frequencies Δn decreases with increasing frequency (low-frequency relaxation). For high-molecular-weight polymers at high concentration, Δn becomes negative at high frequency and its absolute value decreases with further increase in frequency (high-frequency relaxation). A unified theory for the two relaxations is developed on the basis of a model in which, in the semidilute regime, the rodlike polymer is confined in a cage formed by neighboring polymers and the lifetime of the cage lies between relaxation times of the two relaxations. The low-frequency relaxation is ascribed to end-over-end rotation of the polymer and the high-frequency relaxation to the rotation within a limited angle in the cage. The dependences of relaxation parameters on polymer concentration and molecular weight are reasonably explained by the theory.     

Sulfur-containing polymers. IV. Preparation and properties of poly(sulfenyl thiocarbonates)

Poly(sulfenyl thiocarbonates) have been prepared for the first time by the stepwise condensation of chlorocarbonylsulfenyl chloride with diols and dithiols. The polymers were obtained in high yield. Generally they were crystalline solids and were soluble in chlorinated hydrocarbons. On treatment with benzyl mercaptan in the presence of triethylamine, the polymers afforded a diol, carbonyl sulfide, and a disulfide compound. This reaction was extended to the preparation of alternating copolydisulfides.     

Bounds on mass transport of flow on an inclined plate

Zusammenfassung In der vorliegenden Arbeit wird das Variationsproblem, welches die Schranken für den Durchfluss in turbulenter Strömung auf einer geneigten Platte bestimmt, nach Busse [2] abgeleitet. Es wird die symmetrische Natur der Lösung des Variationsproblems für die ebene Poiseuille-Strömung geprüft. Dies zeigt einerseits Ähnlichkeit und andrerseits Unterschiede zwischen dem Problem der ebenen Poiseuille-Strömung und der Strömung auf einer geneigten Platte.