Alcaloïdes des Homalium: Structure de l'homaline,de l'hopromine,de l'hoprominol et de l'hopromalinol

L'étude chimique de quatre alcaloïdes: homaline, hopromine, hoprominol et hopromalinol, isolés de l'Homalium pronyense Guillaum., aétéeffectuée. La structure du principal d'entre eux, I'homaline, est démontrée commeétant celle du butylène 5-5′ di(méthyl-1 phényl-2 oxo-4 diaza-1,5 cyclooctane)-(2S,2′S). Ces quatre bases constituent un nouveau type d'alcaloïde. La présence dans leur molécule deséléments de la spermine permet de les rattacher au groupe des “Alcaloïdes macrocycliques dérivés de la spermine et de la spermidine?d.¹³     

L'extraction des lanthanides et des actinides par les oxydes d'alkylphosphine : L'extraction del'acide nitrique par quelques dioxydes de diphosphine

The distribution of nitric acid between an aqueous phase of constant or variable ionic strength and a benzene solution of diphosphine dioxide can be explained by the following reactions H⁺_a+ NO_3^-a+ DiPO₀ ? D1PO·HNO₃₀ H⁺_a+ NO_3^-a+ DiPO·HNO₃₀ ? DiPO·2 HNO₃₀ At constant ionic strength, the stability constants K₁″ were determined for the complexes 1,1-DiPO·HNO₃ (98 ± 01 (M)^-1), 1,4-DiPO·HNO₃(44±3 (M)_-1) and 1,5-DiPO·HNO₃ (51 ± 1 (M)^-1). The constants K₁₁″ for the complexes 1,1-DiPO·2 HNO₃ and 1,5-DiPO.2 HNO₃ are respectively 035±001 (M)^-1 and 62 ±0.05 (M)^-1 at 25°. With an aqueous phase of variable ionic strength, values of K₁'=54±7 (M)^-2 for 1,5-D1PO.HNO₃ and K_II'=65 ± 04 (M)^-2 for 1,5-DiPO·2 HN0₃ were obtained     

L'extraction des lanthanides et des actinides par les oxydes d'alkylphosphine: Tome 1. l'extraction de l'acide nitrique par l'oxyde de tri-n-butylphosphine

The distribution of TBPO, water and nitric acid has been measured between an aqueous phase and various inert diluents at 25°. This study allowed the determination of the apparent stability constants for two molecular complexes, TBPO . HNO₃ (K₁=17.5±1.3 (M/l)^-2 (benzene); 20.1±0.8 (M/l)^-2 (toluene); II±2(M/l)^-2 (n-hexane) and TBPO . 2HNO₃.H₂O (K₂=(2.9±0.3) 10^-3(M/l)^-2 (benzene)).     

Etude dans la serie des organosilylazoles : I. Action des halogenures d'alkyle,des chlorures d'acide et des cetones halogenees

The reactivity of organosilylamines of imidazole, pyrazole, 1,2,4-triazole and benzotriazole towards alkyl halides, acidic chlorides and halogenated ketones has been studied. Except for 1-trimethylsilylimidazole, which gives a mixed quaternary salt, reactions with primary halides lead to the corresponding 1-alkylated heterocyclic compounds in high yields; in each case only one isomer is obtained (1-alkyl-1,2,4-triazole and 1-alkylbenzotriazole). Similarly acidic chlorides give 1-acylated derivatives in quantitative yields. Finally α- or β-halogenated ketones show different behaviour and give the addition or substitution products.     

Synthese et etude de celluloses echangeuses d'ions. Leur emploi dans l'epuration des eaux residuaires de l'industrie textile-III: Traitement des eaux residuaires de l'industrie textile par une cellulose greffee par des chaines d'acide polyacrylique et par une cellulose renfermant des fonctions ammonium quaternaire

Modified celluloses previously described have been studied for ability to remove colour from the effluents of textile industry. The lowest dye concentration for which the celluloses are efficient are far below the lowest concentrations in effluents. It appears that the modified celluloses are more efficient than carbon black and are well adapted for the purification of pretreated or rinsing waters. Their abilities to extract surfactants from effluents and so to break emulsions of water with solvents have been examined and appear to be large. The treated waters can be recycled.     

Etude des interferences spectrophotometriques par utilisation d'une matrice d'experiences factorielle

(Use of a factorial design to study interferences in spectrophotometry.) Ozonation of aqueous solutions leads to the formation of hydrogen peroxide and oxalic acid. Hydrogen peroxide is determined spectrophotometrically by the classical method in which TiO·H₂O₂²⁺ is formed, but oxalic acid interferes by forming a complex with titanium. The interference is studied by using a simple factorial design. The results, calculated by linear regression, show the existence of both translational and rotational effects on the absorbance signals.     

Stereochimie de la des benzoates d'argent sur des diesters iododesoxy ns: I- Action des benzoates d'argent sur des di-o-aroyl-1,2 iododesoxy-3 ns-glycerols

The stereochemistry of the reaction of silver benzoates on chiral di-O-aroyl-1,2 iododeoxy-3-sn-glycerols has been reinvestigated. The reaction proceeds either with or without neighbouring group participation, depending on : - possible electrophilic assistance by the silver ion to the ionisation of the substrate (occuring only with dissociated silver salts), - ability of substituants R¹ and R² on the substrates to stabilize a positive charge. Rearrangements are at minimum with R¹ and R² electronreleasing groups in the substrate, silver salts un-or weakly dissociated and bearing a good nucleophile. For one case, a regio- and stereo specific reaction is observed.     

Ouverture d'epoxydes par des acides organiques dans L'H.M.P.T.: nouvelle voie d'acces a des desoxypentopyranosides

The opening of pyranic epoxides with organic acids in HMPA leads to regioselectively esterified methyl deoxy$\text{threo}$pentopyranosides; one of them is a convenient intermediate to provide $\text{erythro}$ isomers.     

L'extraction des lanthanides et des actinides par les oxydes d'alkylphosphine : L'extraction de L'acide nitrique par les oxydes de tri-n-hexylphosphine,de tri-cyclohexylphosphine et de tri-n-octylphosphine

The distribution of nitric acid between an aqueous phase and a solution of THPO, TcHPO and TOPO in benzene was measured at 25°. The apparent stability constants K₁' were found to be 17.2±1.0 (M)^-2 for THPO.HNO₃, 7.0±0.8 (M)^-2 for TcHPO.HNO₃ and 15.2 ± I.I (M)^-2 for TOPO.HNO3. The stoichionetry of the last complex was confirmed in n-octane solution at constant ionic strength in the aqueous phase.     

Transformations thermiques des photooxydes meso des acenes—III: Dimeres de l'o-quinodimethane issu du photooxyde d'anthracene

Thermolysis of the anthracene photooxide 1a, in solution, can afford successively three dimers (I→II→III) the structures of which have been established by NMR and X-ray analysis for the first one. Their origin is the unstable o-quinodimethane diether 3a, coming from 1a by isomenzation, which at 80° dimerizes to 8a (dimer I) by an unusual [_π8_s+_π6_s] concerted cycloaddition. Above 110°, 8a isomerizes into 9a (dimer II) by a concerted [1,5] suprafacial sigmatropic migration. Finally, at higher temperature (~200°), both dimers are partly converted into the symetrical dimer 10a (dimer III), probably by a radical pathway. Thermolysis runned in presence of N-methylmaleimide show the non-reversibility of these reactions, giving two adducts, 15a and 16a, derived from 9a, the structures of which are deduced from NMR data. An explanation of the nature and high selectivity of the proceeding processes is given by considering orbital factors.     

Etude des aldimines lithiees : III. Action des epoxydes et synthese d'amino-2 et d'hydroxy-2 tetrahydrofurannes

The reaction of lithiated aldimines, prepared from activated amides, with epoxides leads to good yields of 2-aminotetrahydrofurans (neutral hydrolysis) and 2-hydroxytetrahydrofurans (acid hydrolysis). Various epoxides were examined.     

Sels d'alkyloxyphosphonium—XVI: Activation de l'hydroxyle anomere des 2,3,4,6 tetra-o-acyl-d-mannopyranoses

The joint action of tris(dimethylamino)phosphine-carbon tetrachloride on a tetra-O-acyl-2,3,4,6-d-mannopyranose leads to one α anomeric oxyphosphonium chloride (ATDP salt). This salt is not isolable, but decomposes to yield an anomeric mixture of 1-chloro derivatives. The reaction with alcohols give rise to the formation of orthoesters while thiophenol reacts to yield only the β-thiomannoside. These results are discussed and interpreted.     

Sur l'Utilisation d'une electrode ponctuelle dans les cellules à oxyde electrolyte solide. II. Application a la détermination des tensions d'oxydoreduction des defauts ponctuels dans l'electrolyte

A method is described for direct measurement of oxidoreduction potential of point defects dissolved in solid electrolytes. Measurements were carried out with several solid oxide electrolytes based on zirconia ZrO₂ and hafnia HfO₂.Results allowed us to determine more accurately the electrolytic behaviour of these materials and the reactions involved in the electrochemical blackening of zirconia.     

Reactions de decomposition thermooxydante des polymeres d'episulfures

Thermal oxidations of polymers and oligomers of episulphides have been studied between 150 and 250° by measurements of oxygen absorption. Thermal stabilities of oxidation products have also been studied. It has been shown that oligomers (3,6-dithia-octane; 3,6,9,12-tetrathiatetradecane) resemble polythioethylene in their reactivity towards oxygen. Thermal oxidation of the polythioethers is accompanied by degradation caused by the formation of unstable sulphoxide groups.     

Synthese et etude de celluloses echangeuses d'ions. Leur emploi dans l'epuration des eaux residuaires de l'industrie textile—1: Synthese d'une cellulose greffee par des chaines poly (acide acrylique) et d'une cellulose renfermant des fonctions ammonium quaternaire

For use as ion exchangers and particularly as purification agents for textile industrial effluents, cellulose grafted with polyacrylic acid and cellulose substituted by quaternary ammonium functions have been prepared. For both syntheses, the influences of experimental parameters have been studied in detail and the optimum conditions for large-scale preparation have been determined. Large amounts of modified cellulose have been obtained and tested in industry (cf. part III). The grafting by acrylic acid has been carried out by the ceric-ion method; the quaternary ammonium cellulose has been obtained by condensation of cellulose with epoxy propyl triethyl ammonium chloride. Synthesis of this salt in the presence of cellulose has been achieved so that the quaternary ammonium cellulose can be obtained from cellulose and epichlorhydrin in one step.     

Protonation en milieu anhydre d'aziridines,ylures d'azomethine potentiels : Nature des entites formees et etude des divers equilibres

Protonation of aziridines, which are potential azomethine ylides when the equilibrium aziridine?azomethine ylide is established, generally leads to functional iminium salts. A competition between N-protonation of the aziridine and C-protonation of the azomethine ylide may be observed. Factors governing the different acido-basic equilibriums are discussed.     

Utilisation de l'effet overhauser,des mesures de relaxation en RMN 1H et des deplacements chimiques en RMN 13C dans l'etude de la conformation des amides—II: Application a l'etude conformationnelle d'amides alicycliques: acyl-prolines

¹H and ¹³C chemical shifts in the two decoalesced rotamers of the deuteromethyl ester of N-acetyl-l-proline are established by use of NOE and relaxation measurements. This requires the previous determination of the rotational barrier ΔG_c^≠ and the measurement of the relaxation times T₁ of the α-proton in the two conformers. The observed results reinforce the previous structural conclusions inferred from ¹³C studies on several acyl l-prolines and hydroxy l-prolines. The introduction of an acyl group in the prolines does not affect the different carbon atoms of the cycle in the two rotamers in the same way. These results can be interpreted in terms of electric field effects by the examination of X-Pro dipeptides with the N-terminal amino group shifted from α (COCH₂NH₂) to δ position (CO(CH₂)₄NH₂).     

Addition regioselective d'enolates de cetones aux α-enones: Influence des facteurs steriques sur l'orientation et la reversibilite des reactions

Regio and stereochemistry in the addition of preformed magnesium and lithium ketone enolates (1 to 8) to α-enones (10 and 11) have been examined. When the substitution degree of the enolate is increased the formation of δ-diketone is favoured; nevertheless a good efficiency in the synthesis of the γ-ethylenic β-ketols (1-2 addition) is obtained via bromomagnesium enolates (EMgX) under kinetic conditions. Lithium enolate (ELi) and, chiefly magnesium enolates (E₂MgX) give preferentially the Michael addition. Reversibility from 1-2 to 1-4 addition is commonly observed but the stereochemistry, if any, of the diastereoisomeric δ-diLetones may be quite different when using EMgBr or E₂Mg as starting enolates.     

Formation d'enolates cetoniques par action d'organomagnesiens mixtes dans l'hexamethylphosphorotriamide sur des esters. : Direction des enolisations,limites, utilisation a la preparation de cetones

Alkylmagnesium halides in HMPA react with aliphatic esters to form predominantly the less substituted ketonic enolates. The direction of these enolizations is more selective than that of intermediate ketones. Aliphatic esters are only slightly or not at all enolized under these conditions. Hydrolysis, deuterolysis and alkylation of the ketonic enolates give the corresponding ketones. Benzoic acid derivatives and α-β unsaturated aliphatic and aromatic esters give only low yields of ketonic enolates. The low enolization of the intermediate ketones by these alkylmagnesium halides can explain this result.