Syntheses a l'aide de sulfones : XXIII. Sur la selectivite de la synthese des sulfones Allyliques

The role of the palladium ligands on the yield and regioselectivity of the reaction of conjugated dienes with arenesulphinic acids (or of allylic acetates with sodium arenesulphinates) has been investigated. Arenesulphinic acids catalyse the isomerisation of allylic sulphones.     

Sur une nouvelle synthèse et les caractéristiques chimico-physiques du picolylidène-2-bis-(p-phénylsulfate de sodium) (DCI: «Picosulfate de sodium»)

The synthesis of 2-picolylidene-bis-(p-phenylsulfuric acid) disodium salt (I, DCI: ‘sodium picosulfate’) has been realized by two routes. I has been characterized by the usual analytical data and UV., IR. and PMR. spectral properties.     

Synthèse et étude physico-chimique de sulfures,sulfoxydes et sulfones en série thiazolique

The alkylation of Δ⁴-thiazoline-2-thiones under phase transfer catalysis conditions leads to the corresponding thioethers in good yields. The oxidation of 2-alkylthiazoles with m-chloroperbenzoic acid leads to the corresponding sulfines or sulfones depending on experimental conditions in yields of about 80-90%. The characteristic gle, tlc, ir, ¹H nmr and ms data are reported for most of the compounds studied.     

Analyse en spectroscopie infrarouge, de la structure des complexes BF3 du méthanol, des méthanols deutériés et de l'acide acétique Comparaison de la liaison hydrogène et de la liaison donneur-accepteur

A study of the infrared spectra led to the conclusion that the 2-1 complexes formed from two molecules of methyl alcohol or acetic acid and one molecule of BF₃ have an open structure. One methyl alcohol molecule is linked by hydrogen bonding to a second molecule which is attached to BF₃. The consequences of the addition of BF₃ to the OH (OD) vibrators are similar to those of the formation of a hydrogen bond: elevation of the wave number of the in-plane bending vibration and lowering of the wave number of the stretching vibration compared with the monomer.     

Déplacements Chimiques du Carbone 13, Constantes de Couplage 1J(CH) et 3J(CH) dans une série de dérivés trisubstitués du benzène

¹³C chemical shifts, 1-bond and 3-bond (meta) ¹³C? H coupling constants have been determined in a series of trisubstituted benzene; the substituents are Cl, NH₂, N(C₂H₅)₂, N(iC₃H₇)₂, N(C₂H₄)₂O. Chemical shifts are only in moderate agreement with the usual additivity rules. Additivity rules relative to the above mentioned coupling constants are proposed. With few exceptions, the difference between predicted and observed values is less than 10%.     

Synthese d'une nouvelle classe de donneurs: Bis(selenopyrannylidenes)-4:4′(BSeP)

We report here the first synthetic method to reach biselenopyranylidenes derivatives from either the selenopyrylium ions or the corresponding selenopyranethiones. TCNQ and DDQ complexes are described.     

Copolymérisations de l'acrylonitrile. XII. Phénomènes de solvatation préférentielle et effet de conversion dans la copolymérisation (acrylonitrile–styrène)

Kinetic deviations with the conversion observed in free-radical-initiated [acrylonitrile (A)–styrene (S)] copolymerization carried out in DMF solution have been interpreted in terms of preferential solvation of the polymer by one of the monomers or the solvent. First it is well established that the initial styrene content of the PAS copolymer increases if a slight amount of polymer is introduced before the beginning of polymerization. Next the preferential solvation has been studied and characterized in various solvents (toluene or DMF) from the results of differential refractometry at dialysis equilibrium of the ternary solution (solvent–monomer–polymer) versus its solvent mixture. It was found that the most polar monomer, acrylonitrile, is already adsorbed by the polymer, mostly in copolymerizations carried out in DMF, from initially rich acrylonitrile mixtures. It is suggested that this phenomenon implies a heterogeneous repartition of the monomer mixture in the solution, which may affect the kinetic copolymerization when the conversion increases.     

Synthese stereospecifique de l'ester methylique de l'acide amino-2 oxo-8 epoxy-9,10 decanoique (2s,9r) N - protege.

The first stereospecific synthesis of methyl (2S,9R) N-tBOC 2-amino 8-oxo 9,10-epoxydecanoate has been carried out by using two steps allowing a chirality control: a stereospecific alkylation of the Schiff base 4 and Sharpless epoxidation of the allylic alcohol 6.     

Construction de complexes tétranucléaires de ruthénium à ossature planaire par condensation de deux unités diruthénium à l'aide de ligands pontants: Synthèse et structure moléculaire de [Ru4(CO)8{μ2-P(Cy)2}4] et de [Ru4(CO)8{μ4-P(Cy)}2{μ2-P(Cy)2}2] (Cy = cyclohexyl)

Assembly of Tetranuclear Ruthenium Complexes with Planar Metal Core by Condensation of Two Diruthenium Units Using Bridging Ligands: Synthesis and Molecular Structure of [Ru₄(CO)₈{μ₂-P(Cy)₂}₄] and [Ru₄(CO)₈{μ₄-P(Cy)}₂{μ₂}₂](Cy = Cyclohexyl) The dinuclear complexes [Ru₂(CO)₆{μ-P(Cy)₂}₂] ( 1 ) or [Ru₂(CO)₄{μ-(HCO₂)}₂{P(Cy)₂H}₂] ( 2 ) react in THF solution at 160° to give the tetranuclear complexes [Ru₄(CO)₈{μ₂-P(Cy)₂}₄] ( 3 ) and [Ru₄(CO)₈{μ₄-P(Cy)}₂{μ₂-P(Cy)₂}₂] ( 4 ), as well as the trinuclear complex [Ru₃(CO)₇(μ₂-H){μ₂-P(Cy)₂}₃] ( 5 ). If the reaction is performed at 200°, the bicapped tetranuclear species 4 is obtained in a higher yield, whereas 3 and 5 are formed in trace amounts only. The phenyl derivatives [Ru₂(CO)₆{μ-P(Ph)₂}₂] ( 6 ) or [Ru₂(CO)₄{μ-(EtCO₂)}₂{P(Ph)₂H}₂] ( 7 ) react in a similar manner to give only the complex [Ru₄(CO)₈{μ₄-P(Ph)}₂{μ₂-P(Ph)₂}₂] ( 8 ), analogous to 4 . The molecular structure of 3 consists of a planar framework of four Ru-atoms, each Ru—Ru bond being bridged by a μ₂-dicyclohexylphosphino ligand. The complex 4 represents a planar rectangular Ru core, both faces being capped by μ₄-cyclohexylphosphinidene ligands and two opposite edges being bridged by μ₂-dicyclohexylphosphino ligands.     

Réactions de Transposition Ionique et de Rétrocycloaddition de Dihydro-3a, 8a Pyrazolo (3,4-b) Indoles Sous l'Impact Electronique

Three isomeric compounds, one having a 3a,8a-dihydropyrazolo (3,4-b) indole, the second an aryl-indolyl-ketone-hydrazone and the third a 1,3,4-triarylpyrazole structure give the same mass spectrum, which results from the superposition of the corresponding spectra of the first two compounds, which equilibrate after ionization. The 3a,8a-dihydropyrazolo (4,3-b)indoles proceeding from the second method of cycloaddition, also have the same fragmentation pathway. This makes a determination of the structure of the compounds formed by the cycloaddition reaction impossible by mass spectrometry.