New Phosphenium Cations and Bis-phosphocations via Condensation between Chlorophosphines or Chlorophospheniums and Trimethylsilyl Derivatives

Abstract

New phosphenium cations of general formula R₂N-P+-X, with a variety of X group (-N=P+R₂, -N=PR₃, -C°N, -C=N=S, OR) are synthesized using trimethylsilyl derivatives as reagents.     

Phosphocyanine Dyes

Abstract

The conjugated organic polymethine salts (cyanine dyes) are widely used in industry. Numerous applications in chemistry (dyes, photochemical sensitizers for photographic emulsions...) and physics (in optical devices, non linear optics and erasable laser disks) have been developed.

We present here a synthetic pathway towards previously unknown phosphocyanine dyes by condensation of N-silylated phosphinimines on carboxonium salts. As the synthesis of these dyes results in the enhancement of the conjugation path, new physical properties are expected. Furthermore their aza-Wittig reactivity allows the obtention of new series, i.e. the reaction with isocyanides lead to original αaminopyridines.     

Synthesis of chiral ionic liquids by ion cross-metathesis: en route to enantioselective water-ionic liquid extraction (EWILE), an eco-friendly variant of the ELLE process

From two initial ILs two other ILs are obtained by simultaneous ion exchange. The hydrophobic ions unite in the hydrophobic layer, whereas the hydrophilic ions gather in water. This protocol is explored as a variant of the ELLE process, in which an enantiomer of a racemic mixture is preferentially extracted with water.     

Anti-virulence strategy against Brucella suis: synthesis, biological evaluation and molecular modeling of selective histidinol dehydrogenase inhibitors

In the facultative intracellular pathogen Brucella suis, histidinol dehydrogenase (HDH) activity, catalyzing the last step in histidine biosynthesis, is essential for intramacrophagic replication. The inhibition of this virulence factor by substituted benzylic ketones was a proof of concept that disarming bacteria leads to inhibition of intracellular bacterial growth in macrophage infection. This work describes the design, synthesis and evaluation of 19 new potential HDH inhibitors, using a combination of classical approaches and docking studies. The IC(50)-values of these inhibitors on HDH activity were in the nanomolar range, and several of them showed a 70-100% inhibition of Brucella growth in minimal medium. One selected compound yielded a strong inhibitory effect on intracellular replication of B. suis in human macrophages at concentrations as low as 5 μM, with an overall survival of intramacrophagic bacteria reduced by a factor 10(3). Docking studies with two inhibitors showed a good fitting in the catalytic pocket and also interaction with the second lipophilic pocket binding the cofactor NAD(+). Experimental data confirmed competition between inhibitors and NAD(+) at this site. Hence, these inhibitors can be considered as promising tools in the development of novel anti-virulence drugs.     

Synthesis in ionic liquids only: access to α-oxo-γ-thio-esters via Mukaiyama coupling

Ionic liquids are solvents general enough to conduct a multi-step process in organic synthesis. We show that both the preparation of starting materials (thioacetals and enoxysilane) as well as their coupling can be realized in such medium.     

The crystal structure of tris (indenyl)uranium (β,β,β-trifluoroethanolate)

The title compound was obtained by reaction of the methyl tris(indenyl) uranium complex with trifluoroethanol. A crystal structure reveals that there are two symmetrically independent molecules in the unit cell. The coordination geometry about the uranium atom is a flattened tetrahedron with three π-bonded indenyl rings and one σ-bonded trifluoroethanol oxygen atom. The U---O bonds are remarkably short. The U---C distances indicate trihapto mode of bonding of the indenyl rings. Variation of the ligand X in the U(C₉H₇)₃X class of complexes would not affect the stereochemistry about the U atom.     

Synthese stéréosélective de la phéromone sexuelle “d''aonidiella citrina” le (3S,5E)-(−)-3,9-diméthyle-6-isopropyle déca-5,8-diene-1-yle acétate

L'élaboration stéréosécifique de la double liaison trisubstituée de l'acétate 1 est réalisée par condensation d'une aldimine -silylée sur l'aldéhyde A issue du (−)-citronellol.     

Lewis acid properties of phosphenium and arsenium cations: Study of their adducts with pyridine

In the growing field of dicoordinated Group 15 cations, the quantitative study of the Lewis acid properties of phosphenium or arsenium cations has not yet been undertaken. Moreover, there are only a few described examples of syntheses of arsenium cations. The aim of this work is to enhance this series and to develop a quantitative comparative study of their complexation with Lewis bases such as pyridine. The observation of the ¹³C NMR C-4 variation in the pyridine ring is a good probe to obtain the apparent equilibrium constant K_c and thus a Lewis acidity scale. Phosphenium cations are more acidic than arsenium cations.     

Measurements of isobaric LLV equilibria of the 1,1,4,4-tetramethyl-2-tetrazene-water binary system: novel experimental approach and modeling essays

Journal of Thermal Analysis and Calorimetry - The present study was carried out in the frame of the optimization of the synthesis process of 1,1,4,4-tetramethyl-2-tetrazene (TMTZ), a prospective...