Contribution a la synthese de prostaglandines

A new general method for grafting the β chain of natural Prostaglandins and homologs is proposed.     

Reduction electrochimique des sulfures de fer application a la mesure de la non stoechiometrie

Iron sulfides Fe_1?xS are electrochemically reduced in chloride medium, at pH=0.2 according to a dissolution process. The coulometric measurement of the Fe(III) amount in the solid and the evaluation of the Fe²⁺ concentration in the solution after electroreduction lead to the determination of the stoechiometry on an amount of solid lower than one milligramme.     

Contribution a la valorisation industrielle des dechets de tanneries: cas de la cimenterie

A contribution to the industrial valorization of tannery waste: the case of cement industry. The present work addresses the possibility of valorization of tannery waste incineration ashes in the cement industry. To this end, the impact of the addition of ashes at various percentages (0, 5, 10, 15, 20, 25, 30, 35, 40, and 45 % in mass) on some mechanical and physical parameters of cement was examined: normal consistency (%), the beginning of setting (hr), the end of setting (hr), the hot expansion (mm), the resistances to compression and to bending (N/mm²) determined on normalized 4x4x16 cm samples. The impact of the treatment environment (20 °C and 100% of relative humidity RH, 30 °C and 70 % RH, 45 °C and 45% RH) was also taken into consideration. The obtained results reveal that the normal consistency, the beginning and the end of setting vary linearly with the quality of added ashes. Above an addition of ashes of 30 %, the end of setting exceeds the standards demanding a maximum of 10 hours. Additionally, the results indicate that whatever the environment treatment may be, the resistances to compression and to bending increase with the increase of the sample age; they vary inversely to the amount of ash addition. The results allow to conclude that for an ash addition of 15 % and after an ageing of 30 days, the resistance to compression is higher than 40 N/mm², thus allowing the production of CPA 400 cement. These results also allow to conclude that samples kept in a humid environment give the best resistances to compression and to bending, by comparison with those kept in a dry environment.     

Recherches sur la synthese totale des alcaloides appartenant a la serie de la carpaine et de la cassine—II : Une synthese totale de la pseudo–conhydrine de type biogenetique

The synthesis is described of t-6-propyl-3-piperidinol (dl-pseudo-conhydrine) in 3 steps from 4-4-ethylenedioxy heptanal. This reaction is similar to that recently suggested for the biosynthesis of 2-propylpiperidine (coniine).     

Synthese D'isoquinoleinediones-5,8 apparentees a la mimocine

Selenic anhydride reacts with 1-methyl-5,8-dimethoxyisoquinoline to give 1-formyl-5,8-dimethoxyisoquinoline. Ceric ammonium nitrate oxidation of 1-(2-methyl-1,3-propanediol-2-aminomethyl)-5,8-dimethoxyisoquinoline derived from 1-formyl-5,8-dimethoxyisoquinoline, does not lead to the expected quinone, On the contrary, under the same conditions, 1-acylaminomethyl-5,8-dimethoxyisoquinolines give the corresponding 5,8-isoquinolinequinones related to mimocine. The intermediate 1-aminomethyl 5,8-dimethoxyisoquinoline was obtained by direct introduction of the aminomethyl funtion, protected by the phthalimido group.     

Application de la RMN du 13C a la determination de la configuration de centres quaternaires en serie alicyclique et hydrate de carbone a chaine ramifiee

Configurational assignments to quaternary centres of 2-(l,3-dithianyl) branched-chain carbohydrates, important intermediates for the synthesis of carbohydrate-containing antibiotics, have been made through natural abundance ¹³C NMR spectroscopy. Configurations of quaternary carbons in 21, 24 and 26 were assigned by comparison with ¹³C spectra of structurally-related alicyclic derivatives 1–16.     

Inequivalence magnetique en serie imidazolidine : Application a la determination de la configuration relative de diastereoisomeres

The magnetic inequivalence of benzylic protons in N,N′-dibenzyl 2- or 4-monosubstituted and 2,4-disubstituted imidazolidines has been used to assign cis configuration to substituents at position 2 and 4.     

Recherches sur la synthese totale des alcaloides appartenant a la serie de la carpaine et de la cassine—III : Deux methodes generales de synthese des ethylenedioxy-4,4 aldehydes

4,4-ethylenedioxy aldehydes 1 can be obtained readily from 1-ethoxycarbonyl 6-methyl hept-5-en 2-one 8 by C-alkylation, followed by hydrolysis, decarboxylation, dioxolane formation and ozonolysis. Alternatively, compounds 1 can be prepared by reacting the Grignard reagent of 1-bromo 4-methyl pent-3-ene 24 with an appropriate aldehyde, followed by oxidation, dioxolane formation and ozonolysis. Compounds of type 1 should prove useful in the total synthesis of carpaine, cassine and related alkaloids.     

Aminophosphines: Influence des Substituants lies au Phosphore sur la Barriere a la Rotation Autour de la liaison P?N et sur la Nucleophilie de L'atome D'azote

The ΔG* values for the barrier to rotation around the P? N bond have been determined in some aminophosphines and are dependent on the substituents bound to the phosphorus atom. The comparison between ³J(P? N? C? H) and ΔG* values indicates that p_π—d_π overlapping between nitrogen and phosphorus is the main effect. The nucleophilic behaviour of the nitrogen atom has been measured by the rate of the chemical exchange between methyl-trifluoroacetate and various aminophosphines: the results of this kinetic study are in good agreement with the NMR conclusions.     

Recherches sur la synthese totale des alcaloides appartenant a la serie de la carpaine et de la cassine—V : Synthese totale de l'acide (±) carpamique

The total synthesis is described of (±) 6-(7-carboxy hept-1-yl) 3-hydroxy 2-methyl piperidine [(±) carpamic acid] in five steps from 1-ethoxycarbonyl 6-methyl hept-5-en-2-one.     

Relations entre la structure electronique des films de passivation formes sur les aciers inoxydables et la susceptibilite de ces derniers a la corrosion par piqures

The passive films formed on 316L stainless steel in various NaCl solutions have been investigated by capacitance measurements (Mott-Schottky study). Pitting parameters have been determined using the galvanokinetic polarisation method. The obtained results reveal the existence of a shallow and a deep donor level localised in the band gap of the semiconducting oxide film. These energy levels are due to iron ions in the tetrahedral and octahedral positions. It also appears that the participation of the deep donor level affects the electric field. The study developed allows us to compare characteristic parameters of the electronic structure of the passive film to those related to pitting susceptibility.     

Contribution a l'etude de la determination du fluor a la surface des metaux par detection des photons gamma prompts de la reaction19F(p, αγ)16O

The 837 keV resonance is used for the rapid and non-destructive determination of the gradient of fluorine on the surface of metallic samples. The precise yield curve of this resonance for thick target and the experimental sensitivity of the method have been determined. With this method less than 5·10^?4 μg·cm^?2 fluorine content can be measured. The resolution is of the order of 1000 Å in aluminium and the concentration profiles can be measured to the depth of 1 μm. The time requirement of a surface analysis is 15–30 min, and 2–3 hrs of a gradient measurement. In addition, this method is simpler and more sensitive than the detection of the 1350 keV alpha-particles from the¹⁹F(p, α_o)¹⁶O reaction.     

Étude thermodynamique de la complexation de l'argent par la pyridazine,la pyrimidine et la pyrazine

The stability constants of the complexes of Ag⁺ ion with pyridazine, pyrimidine and pyrazine as ligands are determined, at 25°C in KNO₃ 0.1 M, using the corresponding metal-complex electrodes.Enthalpies for the two steps of complexation observed are obtained from direct calorimetric measurements, under the same conditions of temperature and medium.A comparison of these values and of the entropies derived from them forms the basis for a discussion of the effects of the relative position of the nitrogen atoms in each heterocycle on their ability to form coordination compounds.