Synthesis and antiproliferative activity of (Z + E)‐1‐[4‐(2‐(cyclopentadienyltricarbonylmanganese)‐2‐oxo‐ethoxy)phenyl]‐1,2‐di(p‐hydroxyphenyl)‐but‐1‐ene against breast cancer cells

This paper describes the synthesis of (Z + E)‐1‐[4‐(2‐(cyclopentadienyltricarbonylmanganese)‐2‐oxo‐ethoxy)phenyl]‐1,2‐di(p‐hydroxyphenyl)‐but‐1‐ene. Two synthetic pathways were explored. The best pathway consisted of the alkylation of 1,2‐bis‐[4‐(tert‐butyl‐dimethylsilyloxy)phenyl]‐1‐(4‐hydroxyphenyl)but‐1‐ene with BrCH₂COOEt. The ester obtained was transformed into the Weinreb amide by reaction with HN(OMe)Me–HCl. The reaction of lithium manganese tricarbonylcyclopentadienide with the Weinreb amide produced 1‐[4‐(2‐(cyclopentadienyltricarbonylmanganese)‐2‐oxo‐ethoxy)phenyl]‐1,2‐di(p‐tert‐butyldimethylsiloxyphenyl)‐but‐1‐ene. The deprotection of phenolic functions of the latter compound led to the formation of the final compound. The Z and E isomers could be separated but the isomerization of these isomers from one to another is an easy process. The Z + E compound 2 was tested against the hormone‐dependent MCF‐7 and hormone‐independent MDA‐MB‐231 breast cancer cell lines. The IC₅₀ values of compound 2 were 4.80 ± 2.00 µm and 4.79 ± 0.70 µm for MCF‐7 cells and MDA‐MB‐231 cells, respectively, which was three times better than the ferrocenyl analogue. Copyright © 2012 John Wiley & Sons, Ltd.     

Speciation of Fe(II) and Fe(III) effect on CaCO3 crystallization

The present work was carried out to investigate separately the effect of Fe²⁺ and Fe³⁺ on the precipitation kinetics and the microstructure of CaCO₃. For this an experimental procedure was proposed. Precipitation tests were made by using the dissolved‐CO₂ degassing method. Both air and nitrogen were employed to strip the CO₂ from a Ca(HCO₃)₂ solution initially rich in this gas. At anoxic medium, it was shown that iron (II) prolongs the nucleation step and decelerates the crystalline growth rate. X‐ray diffraction analysis shows that its presence inhibits calcite and promotes aragonite variety. By using air, the reaction medium is rich in oxygen and iron (II) is rapidly oxidized. Seeing the higher solution pH (> 6.5), iron hydroxide forms before the onset of CaCO₃ precipitation and plays a role of seed permitting to initiate CaCO₃ nucleation. So, contrary to the observed effect of iron (II), the presence of iron (III) accelerates the precipitation rate of CaCO₃. As for iron (II), iron (III) inhibits calcite formation but favored the vaterite variety instead of the aragonite one.     

Entanglement of a quantum optical elliptic vortex

We calculate the entanglement of a generalized elliptical vortex formed by quantized radiation field, using Wigner quasiprobability distribution function for such states. We find a critical squeezing parameter above which the entanglement is less for higher vorticity, which is counter intuitive.     

Crystallization-in-emulsion process of a melted organic compound: In situ optical monitoring and simultaneous droplet and particle size measurements

The crystallization-in-emulsion process allows the production of solid particles exhibiting specific features. Here, the batch crystallization process carried out by cooling a melted oil dispersed as an oil-in-water emulsion was studied. Two experimental set-ups allowing the in situ visualization of the nucleation and growth phenomena occurring in the dispersed liquid phase were developed. Observations in quiescent medium of motionless droplets having a diameter of few tens of micrometers showed that primary nucleation started on the inner surface of the droplets. The fast growth of the crystals consumed all the liquid contained within each droplet and was confined within each droplet by the oil–water interface. Solid polycrystalline particles similar in size to the parent droplets were produced. Dynamic tracking of the transient evolution of the size distributions of the two populations of droplets and solid particles during the cooling process in a stirred vessel was carried out using an in situ optical probe. It was shown that the droplets crystallized very progressively during cooling, starting with the largest droplets and ending with the smaller size droplets since the induction time of primary nucleation was dependent on droplet volume. In dilute conditions (1% wt% of dispersed phase) each droplet was converted into a single solid particle. Secondary nucleation based on inter-droplet collisions was not observed in these conditions.     

The resource-constrained modulo scheduling problem: an experimental study

In this paper, we focus on the resource-constrained modulo scheduling problem (RCMSP), a general periodic scheduling problem, abstracted from the problem solved by compilers when optimizing inner loops at instruction level for VLIW parallel processors. Heuristic solving scheme have been proposed since many years to solve this problem, among which the decomposed software pipeling method. In this method, a cyclic scheduling problem ignoring resource constraints is first considered and a so-called legal retiming of the operations is issued. Second, a standard acyclic problem, taking this retiming as input, is solved through list scheduling techniques. In this paper, we propose a novel hybrid approach, which uses the decomposed software pipeling method to obtain a good retiming. Then the obtained retiming is used to build an integer linear programming formulation of reduced size, which allows to solve it exactly. Experimental results show that a lot more problems are solved with this new approach. The gap to the optimal solution is less than 1 % on most of the tested problem instances and the method appears to be competitive with a recently proposed constraint programming algorithm (Bonfietti et al., Lect. Notes Comput. Sci. 6876:130–144, 2011).     

Conferences/meetings

Conferences/meetings     

<Superscript>99m</Superscript>Tc-Labeled human and camel lactoferrin for detection of <Emphasis Type="Italic">Staphylococcus aureus</Emphasis> infections

Human and camel lactoferrin, were labeled with technetium-99m using a simple technique that yielded a labelling efficiency of 98% and stable complexes over time. The camel Lactoferrin was purified. The proteins were investigated for targeting infections in experimental animals. The biodistribution of those labeled proteins in mice infected with Staphylococcus aureus at the femoral muscle was investigated and test ratios of 3.43 and 3.71 were obtained after 60 min for the camel and the human Lactoferrin, respectively. These values were compared to each other and to those reported in the literature, leading us to conclude that the radiotracers are efficient.     

Phosphorus-ylides: powerful substituents for the stabilization of reactive main group compounds

Phosphorus ylides are 1,2-dipolar compounds with a negative charge on the carbon atom. This charge is stabilized by the neighbouring onium moiety, but can also be shifted towards other substituents thus making ylides strong π donor ligands and hence ideal substituents to stabilize reactive compounds such as cations and low-valent main group species. Furthermore, the donor strength and the steric properties can easily be tuned to meet different requirements for stabilizing reactive compounds and for tailoring the properties and reactivities of the main group element. Although the use of ylide substituents in main group chemistry is still in its infancy, the first examples of isolated compounds impressively demonstrate the potential of these ligands. This review summarizes the most important discoveries also in comparison to other substituents, thus outlining avenues for future research directions.

The application of ylide substituents as strong donor ligands for the stabilization of reactive main group compounds with unusual properties and reactivities is discussed.     

Reversal of Regioselectivity in Asymmetric C−H Bond Annulation with Bromoalkynes under Cobalt Catalysis**

Metal-catalyzed asymmetric C−H bond annulation strategy offers a versatile platform, allowing the construction of complex P-chiral molecules through atom- and step-economical fashion. However, regioselective insertion of π-coupling partner between M−C bond with high enantio-induction remain elusive. Using commercially available Co(II) salt and chiral-Salox ligands, we demonstrate an unusual protocol for the regio-reversal, enantioselective C−H bond annulation of phosphinamide with bromoalkyne through desymmetrization. The reaction proceeds through ligand-assisted enantiodetermining cyclocobaltation followed by regioselective insertion of bromoalkyne between Co−C, subsequent reductive elimination, and halogen exchange with carboxylate resulted in P-stereogenic compounds in excellent ee (up to >99 %). The isolation of cobaltacycle involved in the catalytic cycle and the outcome of control experiments provide support for a plausible mechanism.