Synthesis of 2-substituted indoles by palladium-catalyzed heteroannulation with Pd-NaY zeolite catalysts

Various 2-substituted indoles were prepared by heteroannulation of o-iodoanilines and terminal alkynes in a one-pot reaction with a Pd(II)-NaY zeolite catalyst. The product formation largely depended on the solvent, base, and reaction temperature. The recycled catalyst showed good reusability in the heteroannulation reaction.     

Hydrodynamic equations for attractive particle systems on ℤ

Hydrodynamic properties for a class of nondiffusive particle systems are investigated. The method allows one to study local equilibria for a class of asymmetric zero-range processes, and applies as well to other models, such as asymmetric simple exclusion and misanthropes. Attractiveness is an essential ingredient. The hydrodynamic equations present shock wave phenomena. Preservation of local equilibrium is proven to hold away from the shocks. The problem of breakdown of local ergodicity at the shocks, which was investigated by D. Wick in a particular model, remains open in this more general setup.     

Über Chalkogenolate. 103. Reaktion von Guanidin mit Kohlenstoffdisulfid

On Chalcogenolates. 103. Reaction of Guanidine with Carbon Disulfide The reaction between guanidine and carbon disulfide in cold aqueous acetone leads to guanidinium guanidinodithioformate. In heat the reaction gives guanidinium trithiocarbonate and the guanidinium salt of 4-imino-2,6-dithio-1,3,5-thiadiazine. In ethanolic solution guanidine reacts with carbon disulfide to form guanidinium ethyl xanthate. The prepared compounds have been characterized with chemical methods as well as by means of electron absorption spectra, i.r. spectra, n.m.r. spectra, and mass spectra.     

A Further Extension of Pnictide Oxide Chemistry – Synthesis and Structure of La2AuP2O

The phosphide oxide La₂AuP₂O was synthesized from lanthanum filings, dried La₂O₃, gold pieces, and ground red phosphorus in the ideal 1.33:0.33:1:2 ratio in an evacuated silica tube at 1473 K. Small single crystals were obtained by recrystallization in a NaCl/KCl flux. The structure was determined on the basis of single‐crystal X‐ray diffractometer data: new type, C2/m, a = 1537.3(3), b = 427.39(8), c = 1009.2(2) pm, β = 131.02(1) °, wR₂ = 0.046, 1102 F² values, 38 variables. La₂AuP₂O contains two striking structural motifs: The oxygen atoms are located in La₄ tetrahedra. The latter are cis‐edge‐shared forming polymeric cationic [La₂O]⁴⁺ chains. These cationic units are separated and charge‐balanced by [AuP₂]^4– polyanions which have monovalent gold in distorted trigonal planar phosphorus coordination. Two crystallographically independent phosphorus sites occur in the polyanion, i.e. isolated P^3– besides dumb‐bells P₂^4– (P2–P2 223 pm). La₂AuP₂O, which crystallizes in the form of ruby red transparent crystals, is an electron precise phosphide oxide (4La³⁺)(2Au⁺)(2P^3–)(P₂^4–)(2O^2–).     

Unravelling Malaria Antigen Binding to Antibody‐Gold Nanoparticle Conjugates

Conjugates formed by antibody adsorption to gold nanoparticles (AuNP) have found extensive utilization in immunoassays due to the high surface area and interesting optical and electronic properties of the nanomaterials. Nevertheless, the mechanism of formation of antibody‐AuNP conjugates and their antigen binding characteristics have not been sufficiently explored in terms of specificity and consequent clinical applicability. Dynamic light scattering and related techniques have been successfully employed to detect antigen binding to antibody‐AuNP complexes. Here, a range of different techniques from the bionanotechnology realm have been applied to obtain a detailed picture of a competitive immunoassay for malaria antigen detection, based on fluorescence‐quenching by AuNPs. Both agarose gel electrophoresis and differential centrifugal sedimentation (DCS) analyses provide binding constants in the same order of magnitude, for antibody binding to AuNP and for antigen binding to antibody‐AuNP conjugates. Both techniques are also able to reveal inhibition of antigen binding in the presence of a major blood plasma protein, transferrin (via competitive binding). DCS is further used to show inhibition of the binding of the antigen in the presence of human plasma, a realistic testing condition, of high relevance to the implementation of immunoassays at the clinical level.     

Über Chalkogenolate. 143 [1]. Untersuchungen über Guanidinodithioformiate 5. Kristall- und Molekülstruktur vom S-Methylester der Guanidinodithioameisensäure [2]

On Chalcogenolates. 143. Studies on Guanidinodithioformates. 5. Crystal and Molecular Structure of the S-Methyl Ester of Guanidinodithio Formic Acid The title compound crystallizes with Z = 4 in the monoclinic space group P2₁/c with cell dimensions a = 8.701(5), b = 11.426(8), c = 8.221(4) Å, ß = 125.7(1)°. The crystal and molecular structure has been determined from single crystal X-ray data at 20°C and refined to a conventional R of 0.032 (R_w = 0.039). The structure consists of isolated molecules, which exist as E conformers. The molecules have delocated double-bonds and are linked together by S…?H? N hydrogen bridges.     

Über Chalkogenolate. 169. Reaktion von N,N′-Diphenylformamidin mit Kohlenstoffdisulfid 2. Thermisches Verhalten und spektroskopische Charakterisierung von N,N′-Diphenyl-N-formimidoyldithiocarbamaten

On Chalcogenolates. 169. Reaction of N,N′-Diphenyl Formamidine with Carbon Disulfide. 2. Thermal Behaviour and Spectroscopic Characterization of N,N′-Diphenyl N-Formimidoyl Dithiocarbamates The thermal behaviour of N,N′-diphenyl N-formimidoyl dithiocarbamate solvates (L = H₂O, acetonitrile, dioxane, dimethoxyethane, acetone, and mixed solvates) have been studied by thermogravimetric analysis. The electron absorption, infrared, nuclear magnetic resonance, and mass spectra of these compounds are communicated.     

Synthesis of indenes by the palladium-catalyzed carboannulation of internal alkynes

[reaction: see text] A number of highly substituted indenes have been prepared in good yields by treating functionally substituted aryl halides with various internal alkynes in the presence of a palladium catalyst. The reaction is believed to proceed by regioselective arylpalladation of the alkyne and subsequent nucleophilic displacement of the palladium in the resulting vinylpalladium intermediate.