Morphogenèse,structures physiques et évolution biologique

Morphogenesis, physical structures, and biological evolution. Some biological structures seemed to be explained by an elementary physical model. For example, those studied by Yves Bouligand are liquid crystals. Are they, by the way, simple biological entities? Some examples, supported by an evolutionary argument, allow us to explain that structures that are simple from a physical point of view may be recent from an evolutionary point of view.     

Synthèse d'acétyl-6 et benzoyl-6 indoles

The synthesis of 6-acetyl and 6-benzoylindoles has been carried out via the Hemetsberger reaction. Some aspects of their chemical reactivity were investigated.     

Reactions des cyclopentadienyl phosphines et de leurs derives avec les fer et manganese-carbonyles.

Three kinds of reaction are observed (sometimes simultaneously) when heating together a manganese - or a iron - carbonyl derivative with a cyclopentadienyl phosphine sulfide : a) a desulfuration giving either a P-complex (with Fe(CO)₅)or a free phosphine (with Mn₂(CO)₁₀) b) a partial hydrogenation of the cyclopentadiene nucleus yielding a 1-cyclopentenyl phosphine derivative c) a η-complexation of the cyclopentadiene nucleus giving rise to a ferrocenyl phosphine (with[C₅H₅)Fe(CO)₂]₂) or to a cymantrenylphosphine derivative (with Mn₂(CO)₁₀). Some preliminary experiments are also conducted with a tervalent fulvenyl phosphine which reacts mainly by its p^III group.     

Solubilite des additifs du polyethylene: Methodes et resultats

Some differences have been noticed in papers dealing with the measurement of the solubilities of some additives in polyethylene, depending on the evaluation methods. On the other hand, the results concerning other additives seem not to depend on the measuring methods. This can be confirmed by studying two different additives in the same polyethylene, to represent both situations. An interpretation is then proposed, suggesting that the effect could be due to a modification of the amorphous phase of the polymer.     

Preparation et etude des proprietes complexantes de polycondensats contenant des diazapolyoxamacrocycles dans la chaine principale

Some diazapolyoxamacrocycles have been polycondensed with different difunctional compounds to give polymers and gels. Their synthesis and their complexing properties towards alkali metals and calcium cations are reported.     

Synthese et etude par resonance magnetique nucleaire de complexes olefiniques de l''iridium et du rhodium avec quelques bases de schiff derivees de l''aldehyde salicylique

[M(bds)(cod)] compounds (M = Ir or Rh, cod = 1,5-cyclooctadiene, bds = Schiff's base) have been studied by ¹H and ¹³C NMR.

Signals corresponding to the atoms of the double bond trans to the oxygen atom appear at higher field than those of the trans nitrogen side. ¹ and ¹³C attributions have been related by selective decoupling. Some structural data have been also obtained.     

Nouveau Modele d'Electrode Modifiee a Base de Carbone et de Polymere

Abstract

A new type of modified electrode is proposed, based on the thermosealing of carbon and a polymer in different proportions. The mode of preparation and the performances of this new model of polymer electrode are described in details. The potential range is larger than with other electrodes, particularly in the anodic range. Some performances realized on the behaviour of pharmaceutical compounds are described.     

Catalyseurs d′acylation supportes: Synthese et activite d′amino-4 pyridines fixees sur polymeres

New polystyrene-supported 4-amino pyridines are described. Some of them exhibit a good catalytic activity in acylation reactions.     

Synthese et etude de chlorotricyclopentadienylniobium(IV)

The action of cyclopentadienide anions on (Cp)_2?n(RCp)_nNbCl₂ complexes (n = 2,1 or 0; R = C(CH₃)₃) is reported. In all cases, the formation of tricyclopentadienyl complexes, identified by ESR spectroscopy, is observed. Some tricyclopentadienyl species are able to be transformed by η¹–η⁵ fluctuation. An example of a tricyclopentadienyl complex involving a stereochemical blocking is presented. By use of this intermediate a dicyclopentadienyl derivative of niobium(IV) containing two different rings is selectively synthetized.     

Étude thermodynamique des carbamates de méthyle,d'éthyle et de leur eutectique

Reinvestigation of the equilibrium diagram relative to the ethylcarbamate—methylcarbamate system confirms the results of previous studies. Some thermodynamic functions for these two carbamates and their eutectic mixture are given.     

Organo-cuivreux vinyliques 171. Carbocupration d'alcynes par des organo-cuprates et -cuivreux fonctionnels

Some organocopper and cuprate derivatives, distally bearing a free or protected hydroxyl group, add to alkynes, to give α,ω-bifunctional olefins.     

Preparation et proprietes de quelques sulfures de phospholes fonctionnels

^tBuLi with 1-phenyl 3,4-dimethyl phosphole sulfide 1 in THF, gives a mesomeric anion 4. With aldehydes and ketones, this anion leads to methyl-substituted phospholes (6 and 9), 2-substituted phospholes (8) or 2-substituted 3-methylene phosphol 4-enes (5 and 7). With CO₂ and CH₃COOEt a 2-phosphole carboxylic acid 11 and a 2-acetyl phosphole 10 are obtained, respectively. The spectra of the 2-substituted phospholes are studied in some detail. Some of their chemical properties (dimerization, dissociation and tert-butylation) are also described.     

Synthese de polyalcadienes monochloroformiates. Modification chimique par des alcool,amine et thiol

Some monofunctional polydienes with various extremities are obtained by chemical modification of ω-monochloroformate polymers. The chosen products are an alcohol, an amine and a thiol. The organic compounds are attached to the end of a macromolecular chain by a carbonate, a urethane or a thiolcarbonate link. The resulting polymers are characterized by i.r. and NMR analysis. These modification reactions of end groups may be used as model reactions for polymers having specific properties.     

Dérivés d'énose- et d'ynosephosphonates et composés voisins. Communication préliminaire

Derivatives of enose- and ynosephosphonates and related compounds. Preliminary communication The gem-dibromo terminal enoses 1 and 7 are convenient sources of glycosylacetylenes which upon reaction with phosphorus electrophiles gave the phosphorusbearing acetylenic sugars 4, 5 and 8 . Compounds 5 and 8 underwent cycloaddition reactions leading to isoxazolyl-C-glycosides 6 and 9 respectively. The nitroolefinic sugar derivative 11 gave upon bromination-dehydrobromination the first example of a new kind of potentially useful synthetic intermediates, the gem-bromonitroenose 12 . The enosephosphonate 13 was also prepared from 11 . The diglycosylhydroxylamine 18 represents another type of phosphorus-bearing acetylenic sugar derivative. Some ¹H- and ¹³C-NMR. data relative to the new types of phosphorus-containing sugar derivatives synthesized are given.     

Relations entre les caracteristiques physico-chimiques des charges et les proprietes mecaniques des polymeres (PVC) plastifies et charges

Some rheological and mechanical properties of polyvinyl chloride filled with up to 80 phr CaCO₃ have been evaluated with a view to rationalizing results in terms of polymer/filler interfacial interactions. These interactions have been characterized by inverse chromatography using a series of acid-base vapour probes selected from literature classifications. Both pure and industrially pretreated CaCO₃ samples were employed; in addition, one of the pure materials was surface-modified by exposure to selected vapours in a microwave plasma apparatus. Though the data are not adequate to develop exact correlations linking interaction parameters and the physical properties of the filled systems, it is clear that favourable interaction (wetting, adhesion) states at the polymer-filler interface promote ease of dispersion of solids in the molten polymer, enhance mechanical properties (such as elongation at break and the yield stress in the stress/strain curve of the materials) and reduce the rates at which these properties deteriorate when compounds are exposed to weathering. This preliminary work therefore confirms the apparent importance of interfacial effects to property development in filled polymers, suggests the usefulness of acid-base concepts as an index of these effects, and shows inverse chromatography data to be convenient for their quantification. Plasma treatment appears to be a particularly flexible approach to the tailoring of diverse surface properties in filler particles. Detailed development of the various concepts is indicated.     

Esters phosphoriques,phosphonates et oxydes de phosphine dérivés de sucres. Communication préliminaire

Some sugar phosphates, phosphonates and phosphine oxides, Preliminary communication Some new phosphates of 1, 2-O-isopropylidene-α-D-ribofuranose have been prepared. Reactions of 3-C-cyanomethylidene-3-deoxy-1, 2-O-isopropylidene-5-O-trityl-α-D -erythro-pentofuranose (9) have been studied. On treatment with phosphorus nucleophiles, 9 led to phosphorus bearing branched-chain sugar derivatives. Branched-chain cyanosugars as 15 and 16 prepared by cis-vic-dihydroxylation of 9 constitute interesting potential precursors of new types of cyclic sugar phosphates.     

Caractérisation de nouveaux dérivés et analogues de la nétropsine et identification de leurs intermédiaires de synthèse par spectrométrie de masse FAB

The fast-atom bombardment (FAB) mass spectra of a series of netropsin derivatives and analogues were examined in positive-ion and when necessary negative-ion modes. Behaviour of these derivatives was related to that of oligopeptides. Some compounds protected by t-butoxycarbonyl groups were also investigated using this technique and showed characteristic fragmentations.     

Reaction du cyclopentadienylthallium avec les liaisons P-Cl : Preparation et proprietes des cyclopentadienylphosphines

The reaction of cyclopentadienylthallium with chlorophosphines yields cyclopentadienyl phosphines 1, 4, 6 and 8. Some of their derivatives (oxides, sulfides and methyl iodides) have been prepared. Their NMR shows that phosphorus is mainly bonded to the first position of the cyclopentadiene nucleus. Starting with diphenyl (1,3-cyclopentadienyl) phosphine sulfide 2 we have also studied the Diels-Alder reactivity, the bromination and the metalation of the cyclopentadienyl group. This last reaction allows the synthesis of some new phosphorus substituted fulvenes 16, 17 and 18. We have also prepared the new cyclopentadienylid 19 from the dimeric methyliodide 11.     

Coupures thermiques du type retro-Diels et Alder—II : Une nouvelle synthese du (±) jasmonate de methyle

A synthesis is described of methyl dl-jasmonate and jasmonic acid, from endo-tricyclo [5,2,1,0^2.6] 3,8-decadiene-5-one, by standard procedures in 18% yield overall. One of the main steps is a retro-Diels Alder reaction. Some variations of this sequence are presented.     

Diazo-, azo- et azidoazoles. III. Tautoméric azido/tétrazole dans des nouveaux azidoazoles

Some derivatives of 2-azidoimidazole and 3(5)azido-s-triazole were prepared to investigate the possibility of an azido/tetrazole equilibrium in these compounds. An explanation for observed differences in azido/tetrazole equilibrium between azole series and azine or thiazole series is suggested.