Synthese de nouveaux derives silicies cycliques fonctionnels

Methyl or trimethylsilyl ether derivatives of mono- or di-phenols easily undergo disilylation to give disilylated enol ethers or bis(enoxysilanes) with a 1,4-cyclohexadienic ring which are new classes of intermediates in synthesis. In the case of monophenol derivatives hydrolysis affords stable δ-silyl-β,γ-unsaturated ketones, which are converted to the corresponding conjugated cyclohexenones by desilylation (e.g. 4-allyl-2-cyclohexenone which was previously difficult to prepare). In the case of diphenol derivatives cyclohexanediones are obtained upon hydrolysis. Polysilylation occurs with methyl phenyl thio ether, pyrocatechol and even with o-cresol derivatives, to give new products.     

Enzymes immobilisees—IV : Les vanacryls et leur emploi dans la preparation de nouveaux derives insolubles de la trypsine

Treatment of methacrylyl chloride with vanillin gave the corresponding ester 1 which was polymerized (or co-polymerized with allylic alcohol), to give various polyaldehydes, called vanacryls. These polymers were successfully used for immobilizing trypsin according to the probable scheme: PolCHO + H₂NEnz → PolCHNEnz.     

Synthese de chlorofluorovinylsilanes et de quelques derives

Several chlorofluoroolefins were prepared from 1,1-dichloro-2,2-difluoroethylene via chlorofluorovinylsilanes.     

Fragmentation de derives phenyles de l'isobenzofuranne et de l'isoindole

The fragmentation patterns of two paris of heterocycil compounds are investigated in order to discuss the effect of the nature of the heteroatom.     

Synthese de nouveaux oxydes de tetraphosphines macrocycliques

The direct cycloadditions of two dioxophosphidure dianons with two molecules of an unsaturated dihalide produce unsaturated macrocyclic phosphine tetraoxides that are alkylated on phosphorus. Their reduction by molecular hydrogen is highly selective: the saturated homologues are obtained in excellent yield.     

Structure electronique de derives sulfures—II : Spectres electroniques du cation dithiolylium-1,2 et de ses derives de monosubstitution

The electronic spectra of the 1,2-dithiolium cation and of four monosubstituted derivatives have been studied by CNDO/S method, extended to the third period with inclusion of 3d orbitals. Calculated effects of a substitution by a methyl or a phenyl group are in good agreement with experimental data.     

Stereochimie de derives ferroceniques heteropontes chiraux

The stereochemistry of some α,γ-disubstituted hetero-bridged ferrocenes has been determined and it has been shown that the transformation of tertiary alcohols by AlLiH₄ + AlCl₃ occurs with retention of the functional carbon configuration. The experimental results indicate large steeoselectivity of the nucleophilic reagent on β-substituted hetero-bridged ketones.     

Syntheses d'oxazolidines substituees par l'adamantane et de nitroxydes oxazolidines stables derives de l'adamantane

Adamantane oxazolidine derivatives have been prepared. The corresponding mono and biradicals have molecular shapes well suited to the study of the motion anisotropy in solution.     

Procedes nouveaux de traitement par ordinateur de spectres gamma

The author remarks upon the detailed technique described in an article published in the Nuclear Instruments and Methods. He tries to explain the variety of the gamma-spectrometry programmes. Then the original points of his work is given. These are as follows: criteria of the automatic investigation of the peaks, grouping of the multiplets, the nature of the parameters of the functions to be adjusted, the presentation of the results.      

Synthese de nouveaux acides sulfoniques et de sila-sultones ethyleniques

The sulfonation of 1-sila-3-clopentenes and corresponding silabicyclohexanes by CISO₃SiMe₃ leads to novel ethylenic silasultones which are hydrolyzed to their sulfonic acids. Depending upon the degree of substitution of the double bond or cyclopropane ring, a competition may occur between the usually observed C-Si bond cleavage and the until now more rarely observed CH cleavage. An interpretation of these results is proposed.     

Solvolyses de derives de spiro[2.3]hexyle-4

Solvolysis and acid catalysed isomerisation of spiro[2.3]hexyl derivatives are versatile synthetic routes to 2-(Δ¹-cyclobutenyl)ethyl alcohols and methylenecyclopentanols. The course of the reactions is discussed.     

Syntheses de nouveaux heterocycles pyrroliques: Des thiepino[4,5-c]- et [4,5-b]pyrroles

The reaction of N-methylpryrrole-3,4-dicarboxaldehyde ) I )and N-methylpyrrole-2,3-dicarboxaldehyde ) 2 ) with sulfones affored thiepimo[4,5-c]-pyrrole 6,6-dioxides and the thiepimo[4,5-b]pyrrole 6,6-dioxides, respectively. Attempts to condense sulfides with 1 yielded the thiepino[4,5-c]-pyrrole ring system, however sulfides with 2 resulted in benzo-annelation.     

Sur quelques nouveaux oxyfluorures de structure rutile

Transition metal oxyfluorides with rutile structure have been obtained by various synthesis methods: NiM′³⁺TiO₃F₃, CoM′³⁺TiO₃F₃ (M′³⁺ = V³⁺, Fe³⁺); NiVTiO₄F₂, CoVTiO₄F₂ and NiCoTiO₂F₄. Electric and magnetic measurements indicate a semiconducting and antiferromagnetic behavior.