A Convenient Two-Step Synthesis of Phosphonium Salts from Hydroxyarylalkenylphosphine Oxides

Copyright © 2015 Taylor & Francis Group, LLC. A new two-step method for obtaining of phosphonium salts from phosphine oxides was developed. The method includes a cyclization of the dialkyl-2-(2-hydroxy-5-chlorophenyl)-2-phenylethenylphosphine oxides caused by sulfinyl chloride followed by the ring opening under the action of Grignard reagent

The radiation of cynodonts and the ground plan of mammalian morphological diversity

Cynodont therapsids diversified extensively after the Permo-Triassic mass extinction event, and gave rise to mammals in the Jurassic. We use an enlarged and revised dataset of discrete skeletal characters to build a new phylogeny for all main cynodont clades from the Late Permian to the Early Jurassic, and we analyse models of morphological diversification in the group. Basal taxa and epicynodonts are paraphyletic relative to eucynodonts, and the latter are divided into cynognathians and probainognathians, with tritylodonts and mammals forming sister groups. Disparity analyses reveal a heterogeneous distribution of cynodonts in a morphospace derived from cladistic characters. Pairwise morphological distances are weakly correlated with phylogenetic distances. Comparisons of disparity by groups and through time are non-significant, especially after the data are rarefied. A disparity peak occurs in the Early/Middle Triassic, after which period the mean disparity fluctuates little. Cynognathians were characterized by high evolutionary rates and high diversity early in their history, whereas probainognathian rates were low. Community structure may have been instrumental in imposing different rates on the two clades

Topology of energy surfaces and existence of transversal Poincar\'e sections

Two questions on the topology of compact energy surfaces of natural two degrees of freedom Hamiltonian systems in a magnetic field are discussed. We show that the topology of this 3-manifold (if it is not a unit tangent bundle) is uniquely determined by the Euler characteristic of the accessible region in configuration space. In this class of 3-manifolds for most cases there does not exist a transverse and complete Poincar\'e section. We show that there are topological obstacles for its existence such that only in the cases of $S^1\times S^2$ and $T^3$ such a Poincar\'e section can exist.Comment: 10 pages, LaTe

Acid-base and complexing properties of some δ-hydroxyalkenylphosphine oxides

Four new compounds, asymmetrical phosphine oxides containing 2-hydroxyphenylethenyl fragment in cis-orientation with respect to the phosphine oxide: dibutyl-, diphenyl-, dibenzyl-, and dinaphthyl-2-(2-hydroxy-5- chlorophenyl)-2-phenyl-ethenylphospnine oxides, have been studied in aqueous ethanol (80 vol % of EtOH) by means of potentiometry and spectrophotometry at 25±0.1 C, and their acid-base and complexing properties estimated. © 2013 Pleiades Publishing, Ltd

Synthesis of new 2-[2-(dialkyl(diaryl)-phosphoryl)-2-methylpropyl]quinoline-4-carboxylic acids

© 2015 Springer Science+Business Media New York. [Figure not available: see fulltext.] A Pfitzinger reaction of isatin with 2-methyl-(4-oxopent-2-yl)dialkyl(diphenyl)phosphine oxides was used to synthesize new derivatives of 4-quinolinecarboxylic acids, containing a phosphine oxide fragment, and screening for antimicrobial activity was performed

Finding a Needle in the Haystack: A Technique for Ranking Matches Between Components

Abstract. Searching and subsequently selecting reusable components from com-ponent repositories has become a key impediment for not only component-based development but also for achieving the overall usability of component develop-ment environments and the ultimate re-usability of the components themselves. Component matching, a fundamental aspect of the component search problem, has been a well-studied problem, resulting in many different matching technique

New synthesis of phosphine oxides bearing a 2-methyl-4-oxopent-2-yl substituent

A new approach to the synthesis of substituted phosphine oxides bearing an oxo group at the γ-position to the phosphorus atom was developed. © 2010

Soil–atmosphere exchange of carbonyl sulfide in a Mediterranean citrus orchard

Carbonyl sulfide (COS) is used as a tracer of CO2 exchange at the ecosystem and larger scales. The robustness of this approach depends on knowledge of the soil contribution to the ecosystem fluxes, which is uncertain at present. We assessed the spatial and temporal variations in soil COS and CO2 fluxes in a Mediterranean citrus orchard combining surface flux chambers and soil concentration gradients. The spatial heterogeneity in soil COS exchange indicated net uptake below and between trees of up to 4.6&thinsp;pmol&thinsp;m−2&thinsp;s−1 and net emission in sun-exposed soil between rows of up to 2.6&thinsp;pmol&thinsp;m−2&thinsp;s−1, with an overall mean uptake value of 1.1±0.1&thinsp;pmol&thinsp;m−2&thinsp;s−1. Soil COS concentrations decreased with soil depth from atmospheric levels of ∼450 to ∼100&thinsp;ppt at 20&thinsp;cm depth, while CO2 concentrations increased from ∼400 to ∼5000&thinsp;ppm. COS flux estimates from the soil concentration gradients were, on average, -1.0±0.3&thinsp;pmol&thinsp;m−2&thinsp;s−1, consistent with the chamber measurements. A soil COS flux algorithm driven by soil moisture and temperature (5&thinsp;cm depth) and distance from the nearest tree, could explain 75&thinsp;% of variance in soil COS flux. Soil relative uptake, the normalized ratio of COS to CO2 fluxes was, on average, -0.4±0.3 and showed a general exponential response to soil temperature. The results indicated that soil COS fluxes at our study site were dominated by uptake, with relatively small net fluxes compared to both soil respiration and reported canopy COS fluxes. Such a result should facilitate the application of COS as a powerful tracer of ecosystem CO2 exchange.</p

Synthesis and Antimicrobial Activity of New Dialkyl(diaryl)-2-(5-chloro-2-hydroxyphenyl)-2-(phenylethenyl)pentylphosphonium Salts

© 2018, Pleiades Publishing, Ltd. New dialkyl(diaryl)-2-(5-chloro-2-hydroxyphenyl)-2-(phenylethenyl)pentylphosphonium salts bearing various substituents at the phosphorus atom were synthesized. Antimicrobial activity of the salts obtained was estimated. Derivatives with 2-methoxyphenyl substituents at the phosphorus atom are most active against grampositive bacteria. Herewith, dibenzyl-substituted phosphonium derivatives possess the best antifungal activity

Impact of polyelectrolyte coating in fluorescent response of Eu(III)-containing nanoparticles on small chelating anions including nucleotides

© 2014 Elsevier B.V. The present work introduces a novel route to sense the permeability of the polyelectrolyte layer deposited onto luminescent core. The use of ternary Eu(III) complexes as the luminescent core enables to detect the permeability of the polyelectrolyte layers through the change of the Eu(III)-centered luminescence. The chelating anions, such as adenosine phosphates, glutamic acid and ethylenediaminetetraacetic acid disodium salt were used as substrates. The origin of the fluorescent response is the complex formation of the substrates with the Eu(III) complexes, which is greatly affected by the equilibrium concentration of the substrates at the surface of the core. The latter in turn is influenced by the permeability of the polyelectrolyte layer. The obtained results highlight the impact of the nature of the exterior layer in the penetration of the substrates through the negatively and positively charged polyelectrolyte layers