Etudes sur les matières végétales volatiles CXCVIII. Contribution à la connaissance des farnésènes

The dehydration of farnesols or nerolidols is similar to that of geraniol and nerol or linalool. It yields a mixture of hydrocarbons including trans-β-farnesene, two allofarnesenes, α-curcumene, α-, β- and γ-bisabolenes, and triterpenes. The triterpenes result from dienisation of β-farnesenes or α-farnesenes with β-farnesenes, or dimerization of allofarnesenes.     

Études sur les matières végétales volatiles. CCII. Synthèse d'aldéhyde phénylacétique à partir du styrolène

On treatment of styrolene between 30 and 40°C with performic acid, phenylglycol monoformate is produced.     

Etudes sur les composés organométalliques. XVII. Synthèse du tétracyclohexyltitane

Studies of Organometallic Compounds. XVII Synthesis of Tetracyclohexyltitanium Tetracyclohexyltitanium is prepared by reaction of TiCl₄ or Ti(OC₄H₉)₄ with dicyclohexylmagnesium in pentane or ether at - 30°. Some aspects of its reactivity and its decomposition are described.     

Etudes sur les composés organométalliques V [1]. Action de la pyridine sur les organomagnésiens

By the action of pyridine on various Grignard reagents at room temperature, new diorganomagnesium complexes R₂Mg · 2pyridine (R=Ph, n-Bu, t-Bu and Et) were prepared and analyzed. Anomalous results were obtained with methyl- or benzylmagnesium reagents.     

Etudes sur les composés organométalliques. X [1]. Action d'organomagnésiens sur la benzophénone

Various Grignard reagents and their diorganomagnesium complexes with ether or pyridine have been reacted with benzophenone, using different mole ratios and orders of addition. Analysis of the reaction products has provided information as to probable reaction mechanisms of addition and reduction. A monomeric diorganomagnesium reagent, favoured either by addition of the reagent to the ketone or by complexation of the reagent with pyridine, enhances if possible the reduction reaction.     

Etudes sur les composés organométalliques XIV. Réactivité du tétrabenzyltitane (lère communication)

The reactivity of tetrabenzyltitanium with acetone, benzophenone, butanal, acetyl chloride, butyl acetate, ethyl chloroformate, benzonitrile, propylene oxide, carbon dioxide has been investigated. The results show that tetrabenzyltitanium reacts like benzylmagnesium-chloride. The socalled ‘anomalous reaction’ is observed. Benzonitrile, propylene oxide and carbon dioxide, on the other hand, do not react.     

Etudes sur les composés organométalliques. Partie XXI. Contribution à l'étude de la décomposition du tétracyclohexyltitane

Studies on Organometallic Compounds. Contribution to the Study of Thermal Decomposition of Tetracyclohexyltitanium Thermal decomposition of tetracyclohexyltitanium proceeds in a different manner for the solid compound and for etheral solution. We propose an explanation of the decomposition mechanisms based on radical reactivities and compare our results with previous literature data.     

Etudes sur les composés organométalliques. XI [1]. Action du tétrabutoxytitane sur des solutions de Grignard

The reaction of titanium tetra-n-butoxide with phenylmagnesium bromide inether has been investigated. The species (C₆H₅)₂Mg in the Grignard reagent leads to (C₆H₅)₄Ti, whereas the dimeric species (C₆H₅)₂Mg · MgBr₂ produces an insoluble complex mTi(OBu)₄ · n[(C₆H₅)₂Mg · MgBr₂]. Applied to other Grignard reagents, the use of R₂Mg allowed the preparation of tetrabenzyltitanium, tetracyclohexyltitanium and tetramethyltitanium. Cristalline (C₆H₅)₄Ti and (C₆H₅CH₂)₄ Ti have been isolated.     

Etudes sur les composés organométalliques,XIII [1] Action d'organomagnésiens sur la benzalacétone

The reactions of benzalacetone with n-BuMgBr and PhMgBr have been compared with the corresponding reactions with the diorganomagnesium complexes of ether and pyridine. The results obtained by using different mole ratios of reactants and orders of addition show that the conjugated addition reaction is enhanced if a monomeric diorganomagnesium reagent is available; this condition can be realized either by adding a diorganomagnesium complex to the ketone or by complexing the diorganomagnesium with pyridine. Probable reaction mechanisms for normal and conjugated addition reactions are suggested.     

Réaction d'ylures stabilisés sur des aldéhydosucres: influence de divers facteurs dont la structure de l'aldéhydosucre sur le pourcentage d'isomères géométriques obtenu

Reactions of stabilized ylides with aldehydosugars: influence of some factors, particularly the structure of the aldehydosugar, on the ratio of the geometrical isomers formed Aldehydosugars bearing no cis-substituent on the C-atom β to the carbonyl group ( 2, 3, 6, 7 ) or bearing a substituent without an electron lone-pair ( 5 ) gave, upon treatment with acetylmethylidenetriphenylphosphorane, exclusively the E-isomer, this representing the classical behaviour of aldehydes. On the other hand, aldehydosugars having a lone-pair bearing substituent ( 1, 4, 8, 9 ) gave a mixture of E- and Z-isomers. In the case of most of the aldehydosugars of the latter type (giving some Z-isomer) a partial epimerization of the C-atom α to the carbonyl group took place when the solvent of the Wittig reaction was HCONMe₂. It is probable that the presence of an electron lone-pair in the adequate position inhibits the reversion of the kinetic erythro-betaine, allowing the formation of the Z-isomer and, in particular solvent conditions, a cycloelimination leading to the epimeric aldehydosugar which ultimately reacts to give the epimeric E-enone.     

Polymérisation anionique des diènes. III. Etude thermodynamique de la propagation du butadiène et de i'isoprène par les organo-alcalins

The present work is concerned with the influence of the polymerization temperature on the propagation mechanisms of polyisoprenyl- and polybutadienyl-alkali metals. The thermodynamic parameters of the contact ion pairs and free ions propagations have been calculated. With Li⁺ in dioxane solvent, the vinyl propagation is stereospecific (for isoprene, the propagation is mainly 4–3). In comparison with benzene, the vinyl propagation of the polydienyl-Li contact ions pairs should be due to complexation of Li⁺ by dioxane, an electron donor having a weak dielectric constant. In general, the stereospecificity of the propagation of contact ion pairs decreases with increasing counterion size; little difference has been observed with K⁺ and Cs⁺ ion pairs in dioxane and benzene media. For isoprene, the methyl substituant should have chiefly a steric effect in the propagation of free ions, whereas it should confer a polar character to the isoprene molecule in the presence of ions pairs.     

Polymères à propriétés pharmaceutiques potentielles. III. Etude sur molécules modèles

4-Methyl, 4-octene model molecules of the 1–4 polyisoprenic chain have been chemically modified in corresponding alcohol and chloroformate. These model molecules have been allowed to react with pharmaceuticals such as testosterone, cholesterol, and quinine to link the drug with a carbonate bound. Spectral data of these compounds are compared to those of previously synthetized polymers with potential pharamaceutical properties.     

Etudes sur les composés organométalliques I action du chlorure de benzylmagnésium et du bromure de phénylmagnésium sur le tétrachlorure de titane

The reactions between phenylmagnesium bromide or benzylmagnesium chloride and titanium tetrachloride have been studied. The influence of the introduction order of the reagents is mentioned. Decomposition of the (non-isolated) compounds R_nTiX_4-n is shown to be essentially intermolecular, and rarely intramolecular.     

Etudes sur les composés organométalliques partie XX Sélectivité de l'addition 1,4 de composés benzyliques du titane IV avec la benzylidéneacétone

Studies of Organometallic Compounds, XX. Selectivity of 1,4-Addition of Benzyltitanium Compounds with Benzylildenacetone Tetrabenzyltitanium and dialkoxydibenzyltitanium compounds give essentially 1,4- addition with trans-4-phenyl-3-buten-2-one.     

Sur la Similitude des Déformations du Noyau Cyclohexanonique Induites par les Groupes Tertiobutyle et gem-Diméthyle

X-ray and NMR (250 MHz) data for chlorinated 4,4-dimethylcyclohexanones lead to the following conclusions: carbonyl and chlorine substituent effects on ²J and ³J coupling constants are similar to those observed for 4-tert-butylcyclohexanones. In other respects, the gem dimethyl and the tert-butyl groups induce on the ring similar large ⁴J coupling constants (H-3′? C-3? C-4? C-5? H-5′); the results can be interpreted in terms of local gemoetric deformations and additivity of these deformations. The determination of dihedral angles by Lambert's method and from X-ray data shows the identity of the structures in the solid state and the dissolved state and confirms the great structural similarity between 4-tert-butyl- and 4,4-dimethylcyclohexanone derivatives.     

Etudes par spectroscopie dans l'ultra-violet et le visible, du fullerène C60 en solution dans le n-hexane ou adsorbé sur des solides diélectriques

Ultraviolet and visible spectroscopy studies of the fullerene C₆₀ melted in n-hexane or adsorbed on dielectric solids. Experiments of spectroscopy have been carried out, between the far ultraviolet and the near infrared, with pure C₆₀ or containing endohedral complexes rare gas atom-C₆₀, melted in n-hexane, and also pure C₆₀ adsorbed on surfaces of solids.Several phenomena have been observed: 1. a charge transfer due to the influence of interactions between the molecules of C₆₀ and surfaces of solids, yielding new transitions observed in the far ultraviolet ; and interpreted as super excited states of Rydberg type; 1.1. red and blue shifts for some transitions of adsorbed C₆₀, interpreted on the basis of attractive, or turned repulsive, dispersion forces; 1.1.1. emission processes for several transitions of adsorbed C₆₀, explained on the basis of a resonant coupling between these transitions and modes of the surface plasmon induced by the collective excitations of the C₆₀ molecule; this kind of process might be drawn to the Faraday instability in acoustics.