Synthèse et transformations chimiques des télomères de l'undécène-10 oate de méthyle, 2. Synthèse de diols polyhalogénés

Several telomers of methyl 10-undecenoate were prepared with different telogens and identified by IR and NMR spectroscopy or by GPC. Chemical transformations of these telomers led to new polyhalogenated acids of alcohols having high molecular weights.     

Synthèse de compoisés photoréticulables, 4. Estérification de l'acide acrylique sur les télomères de l'acrylate d'hydroxy-2 éthyle

Several telomers were prepared by redox catalysis from 2-hydroxyethyl acrylate ( 1 ) and telogens such as carbon tetrachloride, methyl trichloroacetate, 1, 1, 1-trichlorotrifluoroethane, and 2,4,4,4-tetrachloro-2-methylbutyric acid ( 2d ), as well as block-cotelomers from 1 and a telomer 4 prepared from chlorotrifluoroethylene and carbon tetrachloride. Polyols ( 3a–d and 5 ) with two to twenty primary hydroxyl groups were obtained. They were esterified with acrylic acid, to obtain new photosensitive compositions. ( 6a–d ).     

Recherche de télomères à activité pharmacologique potentielle, 4. Réactions sur les télomères de l'alcool vinylique

Chlorides of carboxylic acids were grafted on telomers of vinyl alcohol. The yields of grafting were improved by increasing the temperature and the concentration of the reactants. In the range investigated, they do not depend on the DP_n of the telomers, nor on the stoichiometric rates of the reactants. Therefore, the grafting rates are directly related to the initial conditions of the reaction. Modification of the telomers by treatment with ethylene oxide provides more soluble substances, but it does not affect the behaviour of the telomers in grafting reactions. Grafting of 1-(p-chlorobenzoyl)-5-methoxy-2-methyl-3-indolacetic acid ( 9 ) (indomethacin), an antiinflammatory drug, leads to potentially pharmacologically active telomers.     

Etude de la télomérisation du méthacrylate de méthyle par l'acide thioglycolique. Application à la détermination des probabilités de structures des télomères synthétisés

This paper presents a new theoretical method for the determination of the PMMA telomers functionality in order to better control the telomerization reaction. Telomers bearing a functional end‐group are obtained by telomerization of methyl methacrylate with thioglycolic acid, initiated either with 2,2′‐azoisobutyronitrile (AIBN) or with 4,4′‐azocyanopentanoic acid (ACPA). In both cases of initiation, the transfer constants of thioglycolic acid are determined and are respectively equal to 0.672 and 0.674. Then, these results were applied to this new method so as to predict and quantify the several structures of telomers obtained above. This method is based on both contribution of termination and transfer to mercaptan in Mayo's law and allows to quantify all the kinds of macromolecules with their both extremities. The influence of the telogen amount vs the functionality of telomers, that of the initiator concentration and that of the nature of the initiator are investigated and underlined the importance of each factor. Finally, theoretical telomer functionalities are compared with experimental ones by titration of acid functions and are in good agreement.     

Etude structurale des télomères du méthacrylate d'époxy-2,3 propyle avec les thiols

The structure of telomers 5a, b , prepared from 2,3-epoxypropyl methacrylate ( 2 ) and benzenethiol ( 1a ) or 1-dodecanethiol ( 1b ) by UV irradiation, was studied by MS, IR, ¹H and ¹³C NMR spectroscopy. The IR spectra of the products show that thiol addition occurs only at the double bond of monomer 2 . Mono- and diadducts could be isolated by fractionation and were characterized spectroscopically together with higher telomers (10 < DP_n < 200). Coupling constants and chemical shifts were assigned for the mono- and diadducts unambiguously. The tacticity of higher telomers was determined and found to follow the Bernoulli statistics.     

Recherche de télomères à activité pharmacologique potentielle, 2. Télomères de l'acide acrylique et greffage de composés hydroxylés

Several telomers of acrylic acid with carbone tetrachloride were prepared. Their average degree of polymerization, which was between 10 and 50, was determined by several analytical methods (elemental analysis, viscosimetry, and GPC). From the kinetic equations of telomerization a relation between DP _n of these telomers and the experimental conditions is established. Fixation of hydroxylic compounds through direct esterification was studied and it was found that the prepared telomers can be used as hydrosoluble carriers for drugs containing primary alcohol or phenol functions.     

Recherche de télomères à activité pharmacologique potentielle, 5. Réactions sur les télomères de l'acide acrylique

Grafting of alcohols and amines on the telomers of acrylic acid was investigated. Carboxylic functions were activated via acid chlorides, anhydrides, or p-nitrophenyl esters. Activation rates and grafting yields were determined in each case.     

Synthèse et transformations chimiques des télomères de l'undécène-10 oate de méthyle, 1

Redox of radical telomerizations of methyl 10-undecenoate (1) with different telogens such as CCl₄, CCl₃Br, CCl₃CF₃, HPO (OEt)P₂ or different adducts of CCI₄, on vinylidene chloride and chlorotrifluoroethylene, were studied. Chemical transformation of the end of the chains led to the corresponding difunctional compounds. Starting with these last compounds, polycondensation reactions were carried out.     

Synthèse de composées photoréticulables, 7. Télomères des acides acrylique et méthacrylique gréffés par méthacrylate d'époxy-2,3 propyle

Telomers were prepared from acrylic or methacrylic acid and CCl₃Br, C₁₂H₂₅SH, C₁₈H₃₇SH or C₈F₁₇C₂H₄SH by initiation with 2,2'-azoisobutyronitrile. The transfer constant of CCl₃Br and the thiols, which are about 0,03 and 0,5, respectively, were determined. These telomers were used as supports of photopolymerizable functions, which were introduced by grafting of 2,3-epoxypropyl methacrylate, catalysed with dodecyldimethylamine. The reactions were followed by ¹H NMR, elemental analyses, tonometrie, and especially by GPC and titration of the acid functions. The grafting telomers, holding many acrylic functions which react upon UV and electron irradiation, give photoreticulated varnish coatings with very interesting properties.     

Recherche de télomères à activité pharmacologique potentielle, 3. Préparation et toxicologie de supports télomères à fonctions hydroxyles

Several telomers of vinyl alcohol with chloroform and diethyl phosphonate were prepared. Their DP _n were measured by several analytical methods (elemental analysis, NMR spectroscopy, viscosimetry). Their small molecular size, their good water-solubility, and their very low acute toxicity allow to use them as drug-carriers in pharmacological applications.     

Synthèse de polymères α,ω-bifonctionnels par réaction de métathèse. Méthodologie d'approche des différences de réactivité des sites carbéniques en présence

The results of studies of co-metathesis reactions of 1,5-cyclooctadiene ( 1 ) with dimethyl 3-hexenedioate ( 2a ) and for comparison, with 4-octene ( 2b ) and 1,5-hexadiene ( 2c ) are analyzed in order to approximate the relative reactivities of the carbene species and of the different types of double bonds. To this end, the experimental distributions of the first telomers are compared with theoretical ones calculated on the one hand allowing equal probability of arrangement of alkylidene groups and on the other hand allowing a kinetic control of propagation and transfer reactions. In other respects, the possibilities of mass control of the products obtained by the same co-metathesis or by degradation of 1,4-polybutadiene are studied. The results show that the reactivity of the 1,5-cyclooctadiene double bonds is higher than that of the other types of double bonds, this being in agreement with the hypothesis of stabilization of the β-carbomethoxycarbene species by carbene/ester complexation. This stabilization allows us to explain the distribution of α,β-difunctional oligomers in agreement with the hypothesis of kinetic control. The distribution of non-functional oligomers agrees with a random combination of alkylidene groups. This stabilization is compatible with the controlling method of molecular weights in the products obtained by polymerization of cyclooctadiene and also by degradation of 1,4-polybutadiene in the presence of 2a .     

Télomères monofonctionnels du chlorure de vinyle, 2. Cinétique par amorçage radicalaire

Radical telomerizations of vinyl chloride with telogens R? CCl₃, containing alcohol and acid functions in the R group, were carried out. The molecular weights of the obtained products are between 1000 and 10 000. Transfer constants (C_T) were calculated for each case by studying the DP_n (10 to 50) variation as a function of the mole ratio (R) of telogen to monomer. In addition, the functionality of the resulting poly(vinyl chloride) was evaluated from the values of C_T and R.     

Mise au point sur l'analyse par chromatographie par exclusion stérique en milieu aqueux de télomères de l'acide acrylique

In the case of water soluble polymers, the use of size exclusion chromatography (SEC) for the determination of the molecular weight involves numerous difficulties. In order to analyse and determine the molecular weight of acrylic acid telomers we have first tried to obtain a satisfactory and reproducible separation. In this particular case, low-molecular-weight standards are not commercially available. Therefore, we decided to prepare standards based on acrylic acid, either by telomerization with a fluorinated telogen or by polymerization with an initiator bearing a fluorinated group. A calibration curve was obtained from the standards. Telomers of acrylic acid with thioglycolic acid were analysed. This is a general method for determination of DP _n by SEC when there is no standard for the polymers. It can be used in a wide range of DP _n from 1 to 700.     

Télomérisation en milieu aqueux, 1. Télomérisation de l'acide acrylique avec l'acide thioglycolique

The telomerization of acrylic acid with thioglycolic acid (mercaptoacetic acid) in aqueous medium, with various initiators (H₂O₂,Na₂S₂O₈,K₈ thermal initiation and 2,2′-azobis (2-amidiniopropane) dihydrochloride) has been achieved. Thus, we were able to point out the limitation of the chain length due to the transfer agent, which is characteristic of a telomerization reaction. Mono-, di-and tri-adducts were isolated and characterized after esterification of the reaction medium with ethanol, then hydrolized. These various adducts were used as standards for size-exclusion chromatography, and the influence of the reaction parameters (initiator, temperature, quality of solvent, amount of telogen was investigated). We also determined the transfer constant of thioglycolic acid (C_T = 0,47). It is worth to note that knowing this value, it is possible to control precisely the number -average degree of polymerization of this type of reaction. This allowed us to prepare telomers with a 50% final weight concentration in the dry extract, as it was recommended for their use in paper industry.     

Comportement viscosimétrique des télomères acrylate d'éthyle/tétrachlorure de carbone

The intrinsic viscosities of some acrylic telomers prepared by redox catalysis were measured with an Ubbelohde capillary viscosimeter. The variation of density during dilution appears to be a very important parameter. Thus, the viscosimetric results become coherent according to Huggins' theory on polymers, and a calibration curve available for the whole range of molecular weights can be established.     

Synthèse de monoalcools et de monoacides chlorofluorés par télomérisation avec des telogènes chlorofluorés

Telomerizations of chlorofluorinated telogens CF₃CCl₃ and \documentclass{article}\pagestyle{empty}\begin{document}$${\rm Cl\rlap{--} (CFCl \hbox{---} CF}_{\rm 2} {\rm \rlap{--} )}_{\rm n} {\rm CCl}_{\rm 3}$$\end{document} (1 ≤ n ≤ 4) with acrylic, allylic, and vinylic monomers were studied. With allyl alcohol and 2-hydroxyethyl acrylate the corresponding fluorinated adducts 1 and 2 were obtained directly. Vinyl and allyl acetates led to the adducts 4a , b and 5a , b , respectively, which could be transformed into the corresponding acetals and alcohols. Telomerizations of methyl acrylate and methacrylate led to the fluorinated adducts 12a and b in the presence of copper chloride as catalyst or also with iron trichloride in the case of methyl methacrylate. By intramolecular elimination the methacrylate adducts were transformed into the lactons 13 and 14 and the acrylate adducts by reduction into the alcohols 1 and 2 . The same reduction of the methacrylate adduct led to the 2,4,4-trichloro-5,5,5-trifluoro-2-methyl-1-pentanol ( 15 ). Independent on the applied catalyst the telomerization of vinylacetic acid led to the monoaddition product, whereas in the case of methacrylic or acrylic acid the formation of monoadducts or higher addition products was found to depend on the catalyst.     

Synthèse et réactions photochimiques d'homopolymères et de copolymères de la p-vinylbenzophénone et du vinylferrocène

Poly(p-vinylbenzophenone), (poly[1-(4-benzoylphenyl)ethylene]), (PVB) has been synthesized for the first time directly from its monomer p-vinylbenzophenone (VB) the preparation of which was improved. In a second step, copolymers containing blocks of photosensitive VB units separated by isolated quenching vinylferrocene (VF) units have been prepared. PVB and the VB-VF copolymers were irradiated in the presence of isopropyl alcohol in benzene solutions. The benzophenone groups inserted in these macromolecular chains obey the same reaction scheme as the photoreduction of the small molecule of benzophenone. However, recombination of the radicals located along the polymeric chain leads to intra- and intermolecular reactions changing drastically the macromolecular morphology by the formation of cycles and networks and by chain scissions. The quantum yields of the photochemical transformations were measured, but they could not be related quantitatively to morphological parameters. In all cases the ferrocene group inhibits strongly the photochemical reaction.     

Télomérisation de l'isobutylène

The telomerization of isobutene was investigated using redox catalysis, free radical, and particularly cationic initiation. The influence of the initiator on the degree of polymerization and the structure of the telomers was studied. Redox and free radical telomerization with CCl₄ and CCl₃Br were found to permit synthesis and identification of the monoadduct structure. Cationic telomerization gives regular structure compounds and the molecular weights are higher than those obtained by other methods of telomerization.     

Télomères monofonctionnels du chlorure de vinyle, 3. Cinétique par catalyse rédox

A kinetic study of the redox telomerization of vinyl chloride with carbon tetrachloride was carried out. Transfer constants of PVC to the metallic ion (C_Feⁿ), initiation rate (k_i), and functionnality of the resulting telomers were measured. Instantaneous and cumulated polymerization degrees, (DP_n )_i and (DP_n )_cum were determined with the help of a theoretical study. These constants provide a rigorous control of the telomerization of vinyl chloride with RCCl₃, (R containing an alcohol or ester group).     

Fonctionalisation des polyalcadiènes: Étude sur molécules modèles des structures accessibles à partir des polymères de l'isoprène par utilisation de l'isocyanate de chlorosulfonyle

The reaction of chlorosulfonyl isocyanate ( 1 ) with alkenes permits to consider the preparation of lactames and N-chlorosulfonated amides as synthetic intermediates. With the goal to obtain functional macromolecular compounds the use of this reaction was considered for the chemical modification of polyisoprenes having a predominant 1,4- or 3,4-microstructure. With the intention to define the modifications of the microstructures caused by the action of 1 on these polymers, the reaction was studied with models. In this way it was possible to determine the percentages of the formation of lactame and N-chlorosulfonated microstructures for each type of chain arrangement in polyisoprene. On the other hand, the transformations of the N-chlorosulfonated lactames into free lactames, amino acid hydrochlorides, and unsaturated nitriles was studied. This work permits to define the spectral references of the microstructures which may be formed applying the reactions to the polymers. In addition it makes it possible to select the type of chain arrangement in polyisoprene which will lead to functional macromolecular compounds with the highest yields and the best selectivity for special applications.