Salt effects in the base-catalyzed polymerization of unsaturated amide compounds. II. Polymerization of p-vinylbenzamide and acrylamide

In the presence of a variety of inorganic salts, p-vinylbenzamide underwent vinyl-type polymerization by anionic initiators to form the polystyrene derivative, whereas in dimethyl sulfoxide as solvent the aromatic polyamide was always obtained through a proton-transfer mechanism regardless of the presence of the salts. In the presence of of the salts, acrylamide is generally polymerized to the polyamide through a proton transfer reaction.     

Salt effect in the base-catalyzed polymerization of unsaturated amide compounds. IV. Polymerization of p-vinylbenzamide in the presence of LiCl/N,N,N′,N′-tetramethylethylenediamine

In the presence of lithium chloride and N,N,N′,N′-tetramethylethylenediamine, p-vinylbenzamide was polymerized in basic media to form a polymer with structure consisting of units due to both proton transfer and vinyl type polymerization, whereas in the presence of the salt alone the monomer underwent exclusively vinyl type of polymerization to give a polystyrene derivative:      

Ring-opening polymerization of unsaturated alicyclic compounds

The ring-opening polymerizations of cyclooctene, cyclododecene, 1,5-cyclooctadiene, 1,5,9-cyclododecatriene, 3-methylcyclooctene, and 3-phenylcyclooctene have been carried out by using a two-component catalyst system composed of ethylaluminum dichloride and tungsten hexachloride. NMR and infrared analyses of the respective polymers indicate structures which are consistent with a ring-cleavage mode of propagation. No evidence for double-bond shifts or transannular reactions during the polymerizations of 1,5-cyclooctadiene, 1,5,9-cyclododecatriene, 3-methylcyclooctene, and 3-phenylcyclooctene was found. The polymerizability of substituted, unsaturated, mediumsized alicyclic monomers suggests a convenient method for synthesis of certain perfectly alternating terpolymers. Since polymerizations occurred rapidly with little evolution of heat, it was concluded that entropy is a substantial contributor to the free energy of the ring-opening polymerization of medium-sized, unsaturated alicyclic monomers.     

Tributylborine: A catalyst for the polymerization of unsaturated compounds

Summary It was found that tributylborine is a catalyst for the polymerization of styrene and methyl methacrylate.     

Salt effects and the mechanism of electrophilic mercuration of unsaturated compounds

The kinetics of the addition of Hg(OAc)₂ to strained and unstrained alkenes was studied in MeOH solution in the presence of NaOAc. Based on salt effects, the HgOAc ion was shown to be the actual reagent in the reaction of the unstrained alkenes, whereas Hg(OAc)₂ was the reagent in the case of the strained alkenes. The mechanisms of the solvomercuration of alkenes of various structures were proposed.For the previous report seeIzv. Akad. Nauk, Ser. Khim., 1994, 819 [Russ. Chem. Bull., 1994,43, 760 (Engl. Transl.)].Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 2, pp. 344–352, February, 1995.     

Salt effects and the mechanism of electrophilic mercuration of unsaturated compounds

The reaction of Hg(OAc)₂ with bornylene in THF-H₂O and CH₃CN-H₂O mixed solvents (75 25, v/v) was studied. The effects of the addition of NaOAc on the reaction rate and the composition of products were investigated. In the CH₃CN-H₂O mixture, the addition of NaOAc decreases the amount of the rearranged product, fundamentally changes the ratio between the regioisomeric solvoadducts, and promotes the formation of products of Hg(OAc)₂ addition. The reaction proceedsvia an ion pair and free mercurinium ion; the cation of the ion pair and the free mercurinium ion have dissimilar structures.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 3, pp. 544–548, March, 1995.     

Effects of trivalent phosphorus compounds on vinyl polymerization. III. Anionic polymerization of acrylonitrile with triethyl phosphite

The polymerization of acrylonitrile catalyzed by triethyl phosphite was studied. It was found that the order with respect to the monomer concentration varies from two to three, depending on the polymerization temperature. From the results obtained for the molecular weight of the polymer and the phosphorus content in the polymer, it was thought that the zwitterion formed by the addition of triethyl phosphite to acrylonitrile is responsible for the initiation of polymerization. The following equation was suggested for the rate of the polymerization:      

Polymerization of t-butyl thiirane. III. Temperature effect on the stereoelective polymerization

The effect of temperature on stereoelective polymerization of t-butyl thiirane was studied. Although the overall kinetic scheme was not modified by a change of temperature, a strong effect on the stereoelectivity ratio was observed. Very high optical yields were obtained for polymerizations run below 0°C. On the other hand, at temperatures higher than 120°C, the stereoelection is inversed; i.e., the opposite enantiomer is chosen. The stereoselectivity ratio varies with temperature according to an Arrhenius relationship.     

Salt forms of the pharmaceutical amide dihydrocarbamazepine

Carbamazepine (CBZ) is well known as a model active pharmaceutical ingredient used in the study of polymorphism and the generation and comparison of cocrystal forms. The pharmaceutical amide dihydrocarbamazepine (DCBZ) is a less well known material and is largely of interest here as a structural congener of CBZ. Reaction of DCBZ with strong acids results in protonation of the amide functionality at the O atom and gives the salt forms dihydrocarbamazepine hydrochloride {systematic name: [(10,11‐dihydro‐5H‐dibenzo[b,f]azepin‐5‐yl)(hydroxy)methylidene]azanium chloride, C₁₅H₁₅N₂O⁺·Cl⁻}, dihydrocarbamazepine hydrochloride monohydrate {systematic name: [(10,11‐dihydro‐5H‐dibenzo[b,f]azepin‐5‐yl)(hydroxy)methylidene]azanium chloride monohydrate, C₁₅H₁₅N₂O⁺·Cl⁻·H₂O} and dihydrocarbamazepine hydrobromide monohydrate {systematic name: [(10,11‐dihydro‐5H‐dibenzo[b,f]azepin‐5‐yl)(hydroxy)methylidene]azanium bromide monohydrate, C₁₅H₁₅N₂O⁺·Br⁻·H₂O}. The anhydrous hydrochloride has a structure with two crystallographically independent ion pairs (Z′ = 2), wherein both cations adopt syn conformations, whilst the two hydrated species are mutually isostructural and have cations with anti conformations. Compared to neutral dihydrocarbamazepine structures, protonation of the amide group is shown to cause changes to both the molecular (C=O bond lengthening and C—N bond shortening) and the supramolecular structures. The amide‐to‐amide and dimeric hydrogen‐bonding motifs seen for neutral polymorphs and cocrystalline species are replaced here by one‐dimensional polymeric constructs with no direct amide‐to‐amide bonds. The structures are also compared with, and shown to be closely related to, those of the salt forms of the structurally similar pharmaceutical carbamazepine.     

Salt effects in the mercuration of unsaturated compounds. Kinetic evidence for the formation of ion pairs and a solvated ion

The kinetics of mercuration of bornylene and cyclohexene in different solvents in the presence of NaOAc and LiClO₄ has been investigated. Addition of NaOAc sharply decreases the rate of addition reactions of mercuric acetate to bornylene and cyclohexene in alcohols; the main direction of the mercuration of bornylene is the formation of acetoxy-adducts, and the yield of solvo-adducts decreases from 76 % in the absence of NaOAc, to 19 % in the presence of the salt (4·10^–3 mol L^–1). A reaction scheme involving the participation of intermediate ion pairs and a solvated mercurinium ion is suggested and confirmed by a steady-state concentration method. The influence of NaOAc on the rate of the reaction and on product formation is realized through the common ion effect.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 5, pp. 819–826, May, 1994.     

Reductive metalation of unsaturated compounds: the effect of allylic protons

Reductive metalation of alkali metals of hydrocarbons containing labile protons can be accompanied by proton transfer from the hydrocarbon to the derived radical anion and/or dianion. The extent of this reaction as a function of reaction conditions has been studied with trans-1,2-diphenylpropene (I). Three alkali metals, Li, Na and K, and two solvents, diethyl ether (DEE) and tetrahydrofuran (THF) were examined.No significant proton transfer was observed with the Li/DEE, Li/THF or Na/DEE system: the product (III) being the vicinal dianion of (I). In the case of Li/DEE, the limited solubility of the dianion prevented complete conversion of (I) to (III) except in dilute solutions.With Na/THF, substantial amounts of proton transfer occurred to form the substituted allylic anion (V) from (I). The extent of this reaction could be controlled by varying the temperature and was largely suppressed at 0°.Extensive proton transfer resulted with K/THF. However, in this case the allylic anion (V) so formed was further reduced with dimerization to the tetra-anion of 1,2,5,6-tetraphenylhexane, (IX).     

Studies on the amide compounds ofMirabilis. Jalapa. L

Mirabilis himalaica(Edgew.)Heinerl Var. Chinensis Heimerl belonging to the genus Mirabilis are used in chinese medicine as a remedy for various diseases[1].Its chemical constituents,however, have not been reported so far. we have carried out a detailed chemical investigatigation of the seeds and have isolated two new amides along with three known compounds. The known compounds were identified by comparing their spectral data with those of authentic samples or with those reported in literature as daucosterol[2], bsitoserol[2], boeravinone E[3], in the present note, the structural elucidation of two new amides is reported.     

The effect of humidity on the ozonolysis of unsaturated compounds in aerosol particles

Atmospheric aerosol particles are important in many atmospheric processes such as: light scattering, light absorption, and cloud formation. Oxidation reactions continuously change the chemical composition of aerosol particles, especially the organic mass component, which is often the dominant fraction. These ageing processes are poorly understood but are known to significantly affect the cloud formation potential of aerosol particles. In this study we investigate the effect of humidity and ozone on the chemical composition of two model organic aerosol systems: oleic acid and arachidonic acid. These two acids are also compared to maleic acid an aerosol system we have previously studied using the same techniques. The role of relative humidity in the oxidation scheme of the three carboxylic acids is very compound specific. Relative humidity was observed to have a major influence on the oxidation scheme of maleic acid and arachidonic acid, whereas no dependence was observed for the oxidation of oleic acid. In both, maleic acid and arachidonic acid, an evaporation of volatile oxidation products could only be observed when the particle was exposed to high relative humidities. The particle phase has a strong effect on the particle processing and the effect of water on the oxidation processes. Oleic acid is liquid under all conditions at room temperature (dry or elevated humidity, pure or oxidized particle). Thus ozone can easily diffuse into the bulk of the particle irrespective of the oxidation conditions. In addition, water does not influence the oxidation reactions of oleic acid particles, which is partly explained by the structure of oxidation intermediates. The low water solubility of oleic acid and its ozonolysis products limits the effect of water. This is very different for maleic and arachidonic acid, which change their phase from liquid to solid upon oxidation or upon changes in humidity. In a solid particle the reactions of ozone and water with the organic particle are restricted to the particle surface and hence different regimes of reactivity are dictated by particle phase. The potential relevance of these three model systems to mimic ambient atmospheric processes is discussed.     

Vinyl polymerization by metal complexes. III. Vinyl polymerization initiated by oligoamide and cupric ion system

Polymerization of methyl methacrylate and other vinyl monomers was studied in the presence of oligoamide (?-aminocaproic acid, its dimer, trimer, tetramer, and pentamer) and cupric ion in aqueous media. The polymerization was found to be of free-radical character and selective for the type of vinyl monomer. Carbon tetrachloride can accelerate the polymerization. The initiation mechanism of the polymerization is discussed. Spectroscopic measurements were indicative of formation of 1:1 complex between oligoamides and cupric ion in aqueous NaClO₄ solution. Some chemical and physical properties of the resulting polymers were measured.     

Lactam and acid amide acetals. 63. Reaction of amide acetals with enaminodicarbonyl compounds

Corresponding dienediaminodicarbonyl compounds were synthesized by the reactions of a series of dimethylaminomethylenedicarbonyl compounds with N,N-dimethylacetamide and N-methylcaprolactam diethylacetals. In the reaction of N-methylvalerolactam diethylacetal, the process is accompanied by a rearrangement with the formation of a 3-methylenepiperidon-2-one derivative. It was found that the introduction of a substituted amino group into the meso-position of the intermediate -alkoxyenamine (in the preparation of dienediaminodicarbonyl compounds) takes place intermolecularly, and a general scheme of the unusual reaction studied has been proposed.For communication 62, see [1].Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 2, pp. 218–223, February, 1991.     

Kinetics of radical polymerization, LVI. Investigation of the effect of molecular inhibitors on the radical polymerization of p-methyl-styrene. c-nitroso compounds

The inhibitive effect of p-nitroso aniline derivatives was studied for the bulk polymerization of p-methyl styrene (pMS). The compounds p-nitros-N,N-dimethyl-aniline (p-NDMA), p-nitroso-N,N-diethyl-aniline (p-NDEA) and p-nitrosodiphenyl-amine (p-NDPA) are strong inhibitors of pMS polymerizations. The inhibition period is directly proportional to the initial concentration of the inhibitor; thus, no side reaction takes place. After the inhibition period the polymerization with p-NDMA and with p-NDEA proceeds at a rate equal to that of the sample without inhibitor, while p-NDPA causes a slight secondary retardation. The value of the stoichiometric coefficient (μ) is lower than the theoretical one. This stoichiometric anomaly can be interpreted in terms of the hot radical theory.