Yves Madaule

A synthetic pathway to macrocyclic and optically active pentamethinium salts

Abstract The design of new types of azodyes with optical activity and macrocyclic structure was achieved by the generalization of the reaction of stabilized carboxonium ions with various primary and secondary amino compounds.

Synthesis of new pentacarbon chain streptocyanines (pentamethinium salts)

Abstract Pentacarbon chain streptocyanines, symmetrical and dissymmetrical, mono- and dicationic are obtained by action of aliphatic mono- and diamines on pentacarbon carboxonium salts.

Superoxide-induced bleaching of streptocyanine dyes: Application to assay the enzymatic activity of superoxide dismutases

With the aim of developing a novel superoxide dismutase (SOD) activity assay, a series of polymethinium salts (streptocyanines) were prepared and studied for their ability to be reduced by superoxide radical anion generated either from the pyrogallol autoxidation or by the xanthine oxidase-catalyzed oxidation of xanthine. The nonacarbon chain streptocyanine 9Cl(NEt(2))(2) was found to be relatively stable in neutral buffered aqueous solutions, to be reduced at a significant rate by superoxide, and addition of iron-dependent superoxide dismutase (Fe-SOD) prevented its bleaching, thus constituting a good candidate as a possible superoxide indicator in a spectrophotometric SOD assay. The values found to be optimal for a SOD assay were defined as pH 7.4, wavelength 728nm, xanthine and xanthine oxidase as superoxide source, and a reaction time of 5min. Based on the color change caused by the superoxide-induced bleaching of the streptocyanine, a qualitative colorimetric method for the SOD activity detection is proposed, enabling visual detection within a short time without any instrument.

Une nouvelle classe de composés anti-parasitaires: les spiroarsoranes. Evaluation in vitro sur la filaire Molinema dessetae

Resume Une nouvelle classe de composes biologiquement actifs, les «spiroarsoranesa a ete synthetisee et leur activite testee in vitro sur la filaire Molinema dessetae . Une importante activite filaricide a pu etre ainsi demontree, avec une faible toxicite.

Group 15 elements in organic synthesis: reactivity of tris(dimethylamino)phosphane and stibane on pyrylium salts

Abstract The reaction of tris-dialkylaminoarsanes on pyrylium salts, giving a new series of pentamethinium salts was extended to the stibanes homologs whereas tris-dimethylaminophosphane yields only phosphonium adducts on the same substrates.

SYNTHESIS OF PENTADIENYLIUM IONS WITH N-SILYLATED PHOSPHAIMINES, CHARACTERIZATION AND REACTIVITY

Abstract By condensation of a carboxonium salt with N-silylated phosphaimines new types of pentadienylium salts are obtained. These new compounds are characterized by NMR spectroscopy, UV and mass spectra. Their aza-Wittig reactivity towards isocyanides is described.

REACTIVITY OF PHOSPHORYLATED PENTADIENYLIUM SALTS TOWARDS ISOCYANIDES: SYNTHESIS OF AMINOPYRIDINE PHOSPHONIUM SALTS

Abstract New cyanines dyes with phosphaimino substituents though engaged in delocalized system react with mono or diisocyanides in an aza-Wittig like reaction to give α-aminopyridines with phosphonium side chain. The final structure was determined by X ray.

Chlorodialkylaminoarsenium salts : synthesis and rirst arsenium reactivity examples

Abstract Chlorodialkylaminoarsenium trifluoromethanesulfonates are obtained by reaction of dichlorodialkylaminoarsanes (R 2 NAsCl 2 ) on silver trifluoromethanesulfonate (CF 3 SO 3 Ag). Their reactivity, (first example of arsenium one), with silylated reagents of the type Me 3 SiX leads either to neutral (X = CN) cyanodialkylaminochloroarsanes or to arsenium salts (X = NMe 2 ) like bis(dialkylamino)arsenium trifluoromethanesulfonates.

Heterocycles organiques de l'arsenic. XI - La prototropie AsIV ⇌ AsV comme voie d'access à la pentacoordination de l'arsenic : Premier exemple☆

Resume Action of As (NMe 2 ) 3 on “cyclen” leads to conformationnaly labile species 1 (“atran” ⇌ “arsoranure”). With CDCl 3 a new reaction occurs giving an arsorane via dichlorocarben addition and prototropic As IV ⇌ As V equilibrium.