Sels d'aziridinium stables,C-fonctionnalisés

Aziridines bearing a functionnality on a ring carbon have been treated with methyl fluorosulfonate to afford the corresponding aziridinium salts in high yields. These compounds were unambiguously characterised by the ring opening reactions using lithium chloride. Two quantitative methods for effecting counter-ion exchange are described.     

Synthèse et caractérisation du phosphate de hafnium comme échangeur d'ions

The preparation, crystalline structure, properties and behaviour of the hafnium bis (monohydrogen phosphate) monohydrate as a cationic exchanger have been studied. The crystalline product has been characterized by elemental analysis, X-ray Powder patterns, thermal analysis, photoelectron spectrometry and infra red spectroscopy. A layered structure in which the hafnium and phosphorus atoms are disposed in such a way as to form zeolitic-type cavities is suggested. The reversibility of the exchange with respect to sodium ions is discussed and can be related to the water content of the exchanger.     

Synthèse et caractérisation de fluorbritholites strontiques dopées au néodyme

Strontium fluorbritholites with the general formula Sr_10-xNd_x(PO₄)_6-x(SiO₄)_xF₂ (0 ≤ x ≤ 6), were prepared by solid state reaction at temperatures between 1200 and 1400 °C. The XRD analysis showed that a pure apatitic phase was formed only for x ≤ 2.5. Above this value, there was formation of secondary phases. The variation of the lattice parameters as a function of x indicated that the formed solid solution was discontinuous on both sides of x = 3. The analysis by Raman and IR spectroscopies confirmed the incorporation of SiO₄ groups within the apatite lattice, and showed that this incorporation induced in the structure a disorder that increased with increasing content of Nd³⁺ and SiO₄⁴⁻. Optical absorption measurements showed a wide variation in the local environment of Nd³⁺ ions, corresponding to the existence of new spectroscopic sites, evidenced by a luminescence study.     

Nouveaux polyéthers et polyesters à base d'isosorbide: synthèse et caractérisation

A new family of multifunctional polyethers was synthesized with acceptable yields by condensation of isosorbide with aliphatic and aromatic dihalides in solid-liquid heterogeneous medium (solid KOH in DMSO). Molecular weights evaluated by GPC are rather low (polydispersed oligomers with n = 2–9). On the other hand, polycondensation with aliphatic or aromatic acid dichlorides in mass or in solution allowed the elaboration of polyethers with appreciable weights (4000–8000) in good yields.     

Synthèse et polymérisation de monomères chlorofluorés allyliques vinyliques et acryliques

Synthesis, polymerization and copolymerization of allylic, vinylic and acrylic monomers containing chlorinated or chlorofluorinated substituents were studied. The reactivity of terminal alcohols or acids is influenced by their neighbouring group. By products and their mechanism of formation were studied.La synthèse et la polymérisation d'acrylates fluorés, a donné lieu à de nombreux travaux. Une première méthode d'obtention de ces composés consiste à faire réagir un alcool fluoré avec un chlorure d'acide insaturé. Les acrylates obtenus sont de la forme :

     

Synthèse et caractérisation de bis acridines pontées en positions 2, 3 ou 4

The preparation of 2,2′, 3,3′ and 4,4′-bridged bisacridines is described. The method consists in the acylation of 2m 3, or 4-aminoacridines in acetone, as the solvent. Ten bisacridines were isolated and characterized by their ¹H and ¹³C nmr parameters. Some of these were tested as potential intercalating agents, but none has shown any activity from this point of view.     

Synthèses et caractérisation de germylènes difonctionnels

Syntheses and caracterization of bifunctional germylenes Several synthetic methods of bifunctional germylenes GeY₂ (Y = RO, PhO, RS, CH₃COO, Acac; Y₂ = OCH₂CH₂O, SCH₂CH₂S) or GeXY (Y = RO, X = Cl; Y = RS, X = Cl; Y = Acac, X = Cl) such as exchange reactions, dechlorhydratation reactions and nucleophilic substitutions from GeCl₂ · dioxane are described. Some more synthesis of divalent species GeY₂ from Ge(OR)₂ by transalcoxylation and from Ge(Cp)₂ by cleavage using protic species will be presented. The stability and reactivity of these germylenes are discussed. Difunctionnal germylenes give generally a selfpolycondensation reactions. However, their reactivity in situ shows a effective participation of monomeric species GeY₂.     

Synthèse de copolymères greffés à base de polyéthylène—1

Polyethylene macromolecular free radical initiators, obtained by ozonization, are used to prepare graft copolymers with methyl methacrylate, styrene and vinyl chloride. The reactions parameters are the number of initiator groups (found by DPPH), peroxide and hydroperoxide proportions (respectively 36 and 64%), decomposition rate (K_d at 90° 10⁻¹sec⁻¹) and monomer concentration. The molecular structure of these copolymers is defined.     

Synthèse d'azido dithiényl-1,2 éthènes et éthanes

Two convenient preparations of azido-1,2-dithienylethenes are described. The synthesis of azido-1,2-dithienylethanes proceeds via metalation (n-Buli) and subsequent treatment by tosylazide of bromo-1,2-dithienyl-ethanes. The structures of the obtained derivatives were established on the basis of ¹H nmr, ir, and mass spectral data.     

Etudes sur les composés organométalliques. XIX. Synthèse et caractérisation de composés alkoxy (alkyl)titane (IV)

Studies of Organometallic Compounds. Synthesis and Characterization of Some Alkoxy (alkyl)-titanium(IV) Compounds Alkoxy(benzyl)titanium and alkoxy(cyclohexyl)titanium compounds are prepared by alcoholysis of tetrabenzyl- and tetracyclohexyltitanium. Structural features are investigated by means of ¹H-NMR.     

Synthèse d'hétérocycles polycondensés à partir de benzopyranno-1 as-triazinones

From benzopyranno-1-as-triazinones 1 and 2 , chloro, hydrazino and aminobenzopyranno-1-as-triazinehsa ve easily been prepared by transformation of the carbonyl function. These compounds lead to triazolo and imidazolobenzopyranno-1-as-triazines by reaction with acids or α-bromoketones. Tetrazolotriazines have been obtained by reaction of sodium nitrite with hydrazinotriazines.     

Oligomérisation anionique de l'ethylène. III. Application à la synthèse d'alcools à longue chaine

Living oligomers of ethylene obtained by n-BuLi complexed with TMEDA have been deactivated by ethylene oxide. The nuclear magnetic resonance study of the product obtained allowed us to follow the influence of TMEDA toward the functionalization. Three products have been characterized: By increasing the ratio [TMEDA]/[n-BuLi] one obtains a decrease of the functionalization reaction.     

Etude sur les composés organométalliques. XVIII. Synthèse et caractérisation du μ-oxo-bis (dicyclopentadiènylméthyltitane IV)

Studies of Organometallic Compounds. XVII: Synthesis and Caracterisation of μ-oxo-bis(dicyclopentadienylmethyltitane IV) (Cp₂TiCH₃)₂O is obtained by reacting (Cp₂TiCl)₂O with methyllithium. IR., NMR. and MS. spectrum are reported. Autocatalytic decomposition of the product is inferred from differential thermal analytic measurements.     

Synthèse et étude de modèles de NADH à noyaux accolés en série pyrrolo[2,3-b] et [3,2-b]pyridines

Pyrrolo[2,3-b] and [3,2-b]pyridines derivatives, precursors for annealated NADH models have been prepared. Several methods for building a pyridinic annealates ring have been used starting from 2- or 3-aminopyrrole. The corresponding dihydropyridine structure leads to highly reactive NADH models compounds and are very much more stable than common models.     

Synthèse de systèmes comportant deux cycles thiophéniques orthocondensés à un hétérocycle à sept chainons

The reduction of the carbonyl group of bithienyls carrying on each thiophene ring a formyl group bonded to the carbon atom next to the intercyclic bond leads to the expected primary di-alcohols. These dialcohols can give the corresponding bis-halogeno-methylated bithienyls. The dehydration of the alcohols and the action of sodium sulfide or amines upon the obtained halides leads respectively to the dihydrodithieno[c,e] oxepines, thiepines and azepines. The tetramethyl derivatives of the previous oxepines have been obtained from diacetylbithienyls.     

Synthèse de sucres aminès ramifiés II. Synthèse et réactions de spiro-aziridines. Communication préliminaire

Treatment of 3-C-cyano-1,2:5,6-di-O-isopropylidene-3-O-(toluene-p-sulfonyl)-α-D -allofurannose with AlLiH₄ or RMgX yields spiro-aziridines with two identical substituents on C(3′) (? H, ? CH₃, ? C₂H₅). Reactions of these products and their derivatives are briefly described. If the C(3′) substituents are protons, the aziridine ring is easily opened. In acidic media (HCl), an amino-sugar containing the branched chain ? CH₂Cl is produced; with hydrogenation, a ? CH₃ branched chain results. If the C(3′) substituents are methyl groups, the aziridine ring cannot be opened neither with HCl nor with hydrogen. The acetylated derivative of this latter compound rearranges to the corresponding allylamide with HCl. For both types of spiro-aziridine, the nitrous deamination leads to the corresponding alkene.