Productive chloroarene C-cl bond activation: palladium/phosphine-catalyzed methods for oxidation of alcohols and hydrodechlorination of chloroarenes

The palladium/phosphine-catalyzed productive chloroarene C-Cl bond activation provides general, efficient, and functional group friendly methods for the selective oxidation of alcohols and the hydrodechlorination of chloroarenes.     

Novel label-free DNA sensors based on poly(3,4-ethylenedioxythiophene)

We report on the design and development of a novel label-free DNA sensor based on conducting poly(3,4-ethylenedioxythiophene) for the direct detection and quantification of target ssDNA.     

Application of a diphosphinidenecyclobutene ligand in the solvent-free copper-catalysed amination reactions of aryl halides

1,2-Diphenyl-3,4-bis[(2,4,6-tri-tert-butylphenyl)phosphinidene]cyclobutene was used as an additive ligand in copper-catalysed amination reactions of halobenzenes with amines in the presence of base to afford the corresponding secondary or tertiary amines in good to excellent yields.     

Rotational-echo double resonance of uniformly labeled 13C clusters

The use of rotational-echo double resonance NMR to measure distances from an observed tightly coupled cluster of 13C spins to a distant 15N, 31P, or 19F is practical if 13C chemical shifts and homonuclear 13C-13C isotropic J interactions are refocused by a combination of rotor-synchronized 13C pi and pi/2 pulses. This scheme is illustrated by experiments performed on diluted and recrystallized L-[13C(3),15N]alanine and L-[13C(6),alpha-15N]histidine.     

RNA cleavage and inhibition of protein synthesis by bleomycin

Bleomycin is a clinically used antitumor antibiotic long thought to function therapeutically at the level of DNA cleavage. Recently, it has become clear that bleomycin can also cleave selected members of all major classes of RNA. Using the computer program COMPARE to search the database established by the Anticancer Drug Screening Program of the National Cancer Institute, a possible mechanism-based correlation was found between onconase, an antitumor ribonuclease currently being evaluated in phase III clinical trials, and the chemotherapeutic agent bleomycin. Following these observations, experimentation revealed that bleomycin caused tRNA cleavage and DNA-independent protein synthesis inhibition in rabbit reticulocyte lysate and when microinjected into Xenopus oocytes. The correlation of protein synthesis inhibition to the previously reported site-specific RNA cleavage caused by bleomycin supports the thesis that RNA cleavage may constitute an important element of the mechanism of action of bleomycin.     

Productive utilization of chlorobenzene: palladium-catalyzed selective oxidation of alcohols

[reaction: see text] The palladium/ligand-catalyzed activation of chlorobenzene provides a general, efficient, and functional group friendly method for the selective oxidation of alcohols to carbonyl compounds.     

A novel microwave-mediated one-pot synthesis of indolizines via a three-component reaction

[reaction: see text] The microwave-mediated three-component reaction of acyl bromide, pyridine, and acetylene is catalyzed by basic alumina to give corresponding indolizines in excellent yields in a one-pot reaction.     

Evaluation of one-centre electron interaction integrals over slater type atomic orbitals

Simplified expressions for one-centre electron interaction integrals in general and Slater-Condon parameters as well as repulsion integrals of the type (aa|aa) in particular have been obtained over Slater-type atomic orbitals. Results calculated using these expressions are in agreement with those due to other authors.     

Diffusion of hydrocarbons in confined media: Translational and rotational motion

Diffusion of monatomic guest species within confined media has been understood to a good degree due to investigations carried out during the past decade and a half. Most guest species that are of industrial relevance are actually polyatomics such as, for example, hydrocarbons in zeolites. We attempt to investigate the influence of non-spherical nature of guest species on diffusion. Recent molecular dynamics (MD) simulations of motion of methane in NaCaA and NaY, benzene in NaY and one-dimensional channels AlPO₄−5, VPI−5 and carbon nanotube indicate interesting insights into the influence of the host on rotational degrees of freedom and orientational properties. It is shown that benzene in one-dimensional channels where the levitation parameter is near unity exhibits translational motion opposite to what is expected on the basis of molecular anisotropy. Rotational motion of benzene also possesses rotational diffusivities aroundC ₆ and C₂axes opposite to what is expected on the basis of molecular geometry. Methane shows orientational preference for 2+ 2 or 1 + 3 depending on the magnitude of the levitation parameter.