Preparation and Antifungal Activity of 3-Iodo- and 6-Iodo-8-quinolinols

 3-Iodo- and 6-Iodo-8-quinolinols were prepared and tested against six fungi: Aspergillus niger, A. oryzae, Myrothecium verrucaria, Trichoderma viride, Mucor cirinelloides, and Trichophyton mentagrophytes in Sabouraud dextrose broth. A comparison with the previously known 5-iodo- and 7-iodo-8-quinolinols showed that the 6-iodo isomer was the most active.     

Theoretical investigation of nonadiabatic and internal temperature effects on the collision-induced multifragmentation dynamics of Na5+ cluster ions

In a continued effort to disentangle adiabatic, nonadiabatic, and internal temperature effects in the collision-induced multifragmentation of alkali-metal cluster ions at moderate energies, we report a theoretical study of this process for the Na5++He encounter in the 100 eV (center-of-mass) collision energy range. The investigation makes use of a diatomics-in-molecules based nonadiabatic molecular-dynamics (NAMD) method. All of the ten electronic 1A' molecular states of the cluster that can be formed by assembling ground-state monomers are considered explicitly. Cross sections for the corresponding 12 possible fragmentation channels are determined. As in the Na4++He case, we find that a few-channel characteristic of adiabatic fragmentation in the electronic ground state dominates. This owes primarily to the dominance of impulsive adiabatic mechanisms. Nonetheless, two significant nonadiabatic transitions take place: electronic excitation during the collision and electronic deexcitation in the postcollision stage. A large amount of the electronic excitation subsequently relaxes into the electronic ground state during the postcollision stage. This important intramolecular vibrational relaxation (IVR)-type mechanism enhances the population of channels characteristic of adiabatic fragmentation in the electronic ground state. The populations of the fragmentation channels are quite sensitive to the internal cluster temperature. This is discussed in terms of the conditions of occurrence of the fragmentation mechanisms and their competition. Comparisons with experimental results are presented and discussed.     

Ni-catalyzed activation of α-chloroesters: a simple method for the synthesis of α-arylesters and β-hydroxyesters

Coupling reactions of α-chloroesters with aryl halides (α-arylation) or carbonyl compounds (Reformatsky) using nickel catalyst allow, under mild conditions, the preparation of various functionalized aryl propionic acid derivatives or β-hydroxyesters. In the synthesis of aryl propionic acid derivatives, the process is efficient with aryl halides bearing either electron-withdrawing or electron-donating groups.     

RAFT-Mediated Emulsion Polymerization-Induced Self-Assembly for the Synthesis of Core-Degradable Waterborne Particles

Poly(N-acryloylmorpholine) (PNAM)-decorated waterborne nanoparticles comprising a core of either degradable polystyrene (PS) or poly(n-butyl acrylate) (PBA) were synthesized by polymerization-induced self-assembly (PISA) in water. A PNAM bearing a trithiocarbonate chain end (PNAM-TTC) was extended via reversible addition-fragmentation chain transfer (RAFT)-mediated emulsion copolymerization of either styrene (S) or n-butyl acrylate (BA) with dibenzo[c,e]oxepane-5-thione (DOT). Well-defined amphiphilic block copolymers were obtained. The in situ self-assembly of these polymers resulted in the formation of stable nanoparticles. The insertion of thioester units in the vinylic blocks enabled their degradation under basic conditions. The same strategy was then applied to the emulsion copolymerization of BA with DOT using a poly(ethylene glycol) (PEG) equipped with a trithiocarbonate end group, resulting in PEG-decorated nanoparticles with degradable PBA-based cores.     

Solid-phase synthesis of 4-methylcarboxy-1,4-benzodiazepine-2,5-diones

A solid-phase synthesis of 1,4-benzodiazepinone-2,5-diones is described. This new route can afford benzodiazepinone bearing a N-urethane-protected amine and a carboxylic acid function. This kind of building block is valuable as a dipeptide mimic or beta-turn mimetic, and it can be introduced in place of any amino acid in peptide synthesis. Using an "analytical probe" strategy, we optimized the synthesis of a model compound on SynPhase Lanterns. Therefore, the efficiency of several linkers was investigated.     

Structural characterization of trimethylsilyl methyl glycosides derivatives by high-resolution mass spectrometry,linked scans and MIKE experiments

Gas chromatography–mass spectrometry investigations have been carried out for the structural analysis of trimethylsilyl methyl derivatives of keto-deoxy sugars and sialic acids studied under electron ionization. Fragmentation patterns were determined. The three derivatives undergo some common fragmentation pathways. Formation of fragment ions possessing cyclic resonance-stabilized structures was demonstrated. As the sialic acid derivative contained a N-acetyl substituent, some additional fragmentations occurred and were also elucidated. Thus, the mechanism of fragmentation was revealed for these derivatives and new findings concerning some series of fragment ions are presented. Presented at the Annual French National Symposium on Mass Spectrometry, Electrophoresis and Proteomics, 20–23 September 2007 in Pau, France.     

Coordination chemistry of phosphole ligands: From supramolecular assemblies to OLEDs

The synthesis and properties of organophosphorus π-conjugated chromophores incorporating metallic ions are described. Their optical and electrochemical properties depend on the metal centre linked to the organophosphorus atom. Moreover, the introduction of metallic ions induces a control of the supramolecular organization of the organophosphorus π-conjugated systems. The specific properties of these complexes make them valuable materials for organic light-emitting diodes and interesting building blocks for the tailoring of novel NLO-phores.     

Sugar-derived tricatenar catanionic surfactant: synthesis, self-assembly properties, and hydrophilic probe encapsulation by vesicles

A new sugar-derived tricatenar catanionic surfactant (TriCat) was developed to obtain stable vesicles that could be exploited for drug encapsulation. The presence of the sugar moiety led to the formation of highly hydrophilic stoichiometric catanionic surfactant systems. The three hydrophobic chains permitted vesicles to form spontaneously. The self-assembly properties (morphology, size, and stability) of TriCat were examined in water and in buffer solution. Encapsulation studies of a hydrophilic probe, arbutin, commonly used in cosmetics for its whitening properties, were performed to check the impermeability of the vesicle bilayer. The enhancement of hydrophobic forces by the three chains of TriCat prevented surfactant equilibrium between the bilayer and the solution and enabled the probe to be retained in the aqueous cavity of the vesicles for at least 30 h. Thus, the present study suggests that this tricatenar catanionic surfactant could be a promising delivery system for hydrophilic drugs.     

Visible‐Light Emulsion Photopolymerization of Styrene

The photopolymerization of styrene in emulsion is achieved in a conventional double‐wall reactor equipped with a LED ribbon coiled around the external glass wall. Styrene mixed to acridine orange is added to the water phase containing sodium dodecyl sulfate, a water‐soluble N‐heterocyclic carbene–borane and disulfide, and irradiated. Highly stable latexes are obtained, with particles up to a diameter of 300 nm. The ability to reach such large particle sizes via a photochemical process in a dispersed medium is due to the use of visible light: the photons in the visible range are less scattered by larger objects and thus penetrate and initiate better the polymerizations. They are also greener and cheaper to produce via LEDs, and much safer than UVs. The method presented does not require any specific glassware; it works at lower temperature and delivers larger particles compared to thermal processes at similar solids contents and surfactant concentrations.     

Fiber grating synthesis by use of time-frequency representations

We propose a method to reconstruct the grating period in fiber grating structures from the field reflection coefficient or the related impulse response. The method is based on the joint time-frequency signal analysis and uses the Wigner-Ville and the spectrogram distributions. Results show good agreement between exact and reconstructed functions.