Relative thermodynamic stabilities of allyl vinyl and propenyl vinyl ethers

The relative thermodynamic stabilities of a number of isomeric allyl vinyl and propenyl vinyl ethers were determined by chemical equilibration in DMSO solution with KOBu-t as catalyst. From the temperature dependence of the values of the equilibrium constant the parameters G _m , H _m and S _m of isomerization at 298.15 K were evaluated. Propenyl vinyl ethers, owing to their low enthalpy contents, are much more stable than the isomeric allyl vinyl ethers. It appears that in the parent propenyl vinyl ether, the Me group attached to C- of the divinyl ether skeleton has a strong stabilizing effect, comparable to that of alkyl groups in ordinary olefins, on the unsaturated system. In more heavily alkyl-substituted divinyl ethers, however, the stabilizing effects of alkyl groups are less prominent, being comparable to the low stabilization energies of alkyl groups in vinyl ethers, and depend moreover, on the pattern of substitution.     

F and C spectra of fluorinated and partially fluorinated vinyl alkyl ethers

Fluorine, hydrogen, and ¹³C NMR spectral data have been obtained for vinyl alkyl ethers containing fluorines. Some of the molecules are perfluorinated and others include hydrogen, bromine, and chlorine substituents. New generalizations regarding FF spin-spin coupling are developed and used, along with previously recognized correlations, in the confirmation of structures and the assignments of resonances. ¹³C spectroscopy, especially the analysis of ¹³C¹⁹F coupling, is critical in several of the structure determinations. Chlorine isotope effects on fluorine chemical shifts are observed when the chlorine and fluorine are attached to the same carbon, and are also used in the structure analyses. Long-range couplings between fluorines in the vinyl group and fluorines in the alkyl group are interpreted in terms of molecular geometry which allows certain of the alkyl fluorines to “touch” the fluorines cis and gem to the ether oxygen but not the fluorine trans to the oxygen. Two bond ¹³C¹⁹F coupling across the vinyl double bond is found to vary dramatically with the electronegativity of the vinyl substituents in the ethers, in accordance with previous observations for olefins.     

9-alkenylcarbazoles

The¹H and¹³C NMR spectra of 9-vinylcarbazole and its 3-chloro, 3,6-dichloro, and 3-nitro derivatives were recorded and studied. It is shown that electron-acceptor substituents reduce the shielding of the -carbon atom and the trans proton of the vinyl group. A good linear correlation between the chemical shifts of these nuclei and the Hammett _para ^– constants with the values (3.78 for¹³C and 0.28 for¹H_trans) is observed. It was established by comparison of the results with the¹H and¹³C NMR spectral parameters for some of the vinyl compounds that the degree of conjugation of the p electrons of nitrogen with the electrons of the double bond in 9-vinylcarbazoles is lower than in simple vinyl and vinyl phenyl ethers and vinyl acetate.See [25] for communication I.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 10, pp. 1368–1371, October, 1976.     

Structure of vinyl ethers of a number of azoles according to1H and13C NMR data and quantum-chemical calculations

NMR¹H and¹³C spectra have been used to establish the conformational states of a number of azole vinyl ethers and to study the nature of the conjugation of the unshared pair of electrons of the oxygen atom with the azole and vinyl moieties. The H¹ NMR spectra of the vinyl ethers of indazole, 4,5-diphenylimidazole, benzimidazole, and 1,2,4-triazole revealed anomalous downfield shifts of the signal of the proton of the vinyl group, which are attributed to specific interactions, resembling weak hydrogen bonds, between these hydrogen atoms and the pyridine nitrogen. This conclusion agrees with the results of quantum-chemical calculations for the vinyl ether of indazole.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 5, pp. 1031–1036, May, 1990.     

Multinuclear NMR (1H,13C,15N,17O) studies of intramolecular interactions in 1-vinylpyridones and quinolones

¹H and¹³C NMR was used to estimate the dihedral angles between the planes of the vinyl group and the hetero ring for 1-vinylpyridones and quinolones. The¹H,¹³C,¹⁵N, and¹⁷O NMR data showed the existence of a specific intramolecular weak hydrogen bond between the -H atom of the vinyl group and the O atom in 1-vinyl-2-pyridones and 2-vinyl-1-isoquinolone.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 7, pp. 1539–1547, July, 1990.     

Study of specific C-H...N intramolecular interactions in heteroaryl vinyl ethers,on the basis of factor analysis of1H and13C NMR spectral parameters

On the basis of a factor analysis of the¹H and¹³C NMR spectral parameters of the vinyloxy group in a broad series of aryl and heteroaryl vinyl ethers, it has been established that these parameters change mainly under the influence of the electronic effect of the aromatic fragment and specific C-H...N intramolecular interaction of the -hydrogen atoms of the vinyl group with an endocyclic nitrogen atom. It has been shown that the parameters most sensitive to the specific C-H...N. interaction are the chemical shifts of the -proton and -carbon of the vinyl group, and also the spin-spin coupling constant between these atoms.Translated from Izvestiya Akademii Nauk SSSR, No. 10, pp. 2289–2297, October, 1991.     

Reaction of the vinyl ethers of heterocyclic imino alcohols with acyl halides

Conclusions The reaction of the vinyl ethers of heterocyclic imino alcohols with acyl halides gave a number of new vinyl ethers of heterocyclic amido alcohols as 11 mixtures of the isomeric 3,6- and 5,6-dihydropyrans, and ³- and ⁴-piperidines.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 11, pp. 2538–2541, November, 1980.     

Sequence-regulated oligomers and polymers by living cationic polymerization. III. Synthesis and reactions of sequence-regulated oligomers with a polymerizable group

New sequence-regulated macromonomers ( 3 ) with a vinyl ether terminal were prepared by the HI/ZnI₂-mediated living cationic polymerization of vinyl ethers: CH₃? CH(OR¹)? CH₂CH(OR²)? C(COOEt)₂CH₂CH₂OCH?CH₂ ( 3a : R¹ = nBu, R² = CH₂CH₂OCOPh; 3b : R¹ = iOct, R² = CH₂CH₂Cl). The synthesis consisted of three consecutive steps: (i) quantitative addition of hydrogen iodide to the first vinyl ether into an adduct [CH₃? CH(OR¹)? l]; (ii) propagation of a second vinyl ether from the adduct in the presence of zinc iodide; and (iii) quenching the resulting AB-type heterodimeric living intermediate with a carbanion [^θC(COOEt)₂CH₂CH₂OCH?CH₂] carrying a vinyl ether group. The HI/ZnI₂-initiated living cationic polymerization of 3a and 3b yielded narrowly distributed polymers $\left( {\overline {DP}} _{_n } \sim 10 \right)$ consisting of a poly(vinyl ether) backbone and sequence-regulated oligomer branches. The terminal vinyl ether function of 3 was also utilized to prepare pentamers and hexamers with controlled sequence of functional vinyl ethers by selective dimerization and chain extension reactions with HI/ZnI₂. © 1993 John Wiley & Sons, Inc.     

Spectroscopic effects and intramolecular interactions in the1H and13C NMR spectra of five-membered N-vinyllactams

In 1-vinylpyrrolidone, 1-vinyl-1,2,4-triazole-5-ones, 1,3-divinylimidazolidine-2-thione, and 1-vinylbenzimidazole-1-thione the vinyl groups exist predominantly in the s-trans-, but in 1-vinyl-4,5-diphenylimidazole-2-ones in the s-cis(0)-conformations relative to the exocyclic heteroatom. In 1-vinylbenzimidazole-2-ones, 3-vinylbenzoxazole-2-one, and 1-vinylindole-2,3-diones the vinyl group is present as a mixture of the s-cis(0)- and s-trans(0)-conformations. According to¹H and¹³C NMR results there are specific intramolecular interactions in 1-vinylpyrrolidone and in 1,3-divinylimidazolidine-2-thione resembling weak hydrogen bonding between the -hydrogen atoms of the vinyl group and the oxygen or the sulfur atom. In 1-vinylsuccinimide, 2-vinylphthalimide, and 1,3-divinyl-4,5-diphenylimidazole-2-one there is the same type of interaction with the -cis-hydrogen atom of the vinyl group, while in 1,3-divinyl-1,2,4-triazole-5-one there is interaction between the same hydrogen atom and the nitrogen atom.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 9, pp. 1983–1990, September, 1990.     

Calculation of the torsional angles in alkyl vinyl ethers from the direct13C-1H spin-spin interaction constants

It is shown that the differences in the direct¹³C-¹H SSIC of the C atom of the vinyl groups in alkyl vinyl ethers depend on the value of the torsional angle about the C bond. This dependence is used to make quantitative estimates of the torsional angles in alkyl vinyl ethers with alkyl substituents ranging from CH₃ to t-C₄H₉ Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 2, pp. 390–393, February, 1991.The authors are grateful to S. V. Kirpichenko for providing the triethylvinylthiosilane, synthesized as described in [11].     

Steric specificity of the direct13C-1H spin-spin coupling constants in the vinyl group in N-vinylpyrroles

Conclusions The direct¹³C-¹H spin-spin coupling constants of the vinyl group -carbon in N-vinyl-pyrroles display steric specificity and change depending on the dihedral angle between the planes of the vinyl group and the heterocycle.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 6, pp. 1418–1421, June, 1987.     

Reaction of Some Dibromomethyl-Substituted Cyclohexadienones with Molecular Bromine

4-Dibromomethyl-4-methyl-2,5-cyclohexadienone and its 2- and 3-methyl-substituted derivatives react with an equimolar amount of molecular bromine in carbon tetrachloride, yielding vinyl bromination products at the -position with respect to the carbonyl group. The reaction of 4-dibromomethyl-3,4-dimethyl-2,5-cyclohexadienone with a large excess of bromine, apart from the vinyl bromination product, gives the corresponding 3-bromomethyl and 3-dibromomethyl derivatives. 4-Dibromomethyl-2,4-dimethyl-2,5-cyclohexadienone takes up bromine molecule at the C ² ÍC ³ double bond.     

Reactions of chelated η-pentadienyl iron complexes with nucleophiles

Ferracyclic (1-3-η³)pentadienyl complexes with electronically decoupled allyl and vinyl moieties were reacted with various heteroatom and carbon nucleophiles. Primary amines selectively attacked neutral (4-6-η³-pentadienyl)ferralactones 2 on the end of the allyl ligand to give 3-(endo-vinyl)-(4-6-η³-allyl)ferralactams 4 and by a similar reaction of the latter eventually 6-(exo-vinyl)-(4-6-η³-allyl)ferralactams 5. -like attack on the conjugated coplanar vinyl residue of 2 was not observed. The cationic η³-allyl complex 3 was attacked by nucleophiles either on the allylic terminus furnishing free (1Z, 3E)-dienes 8, or on the vinyl residue which is part of an activated Michael system to give η⁴-1,3-diene complexes 9. η⁴-1,3,5-Triene complex 10 was obtained with basic nucleophiles.     

Gas chromatographic determination of trace amounts of vinyl chloride and dichloroethenes in landfill-gas

A method for the determination of vinyl chloride (VC) and dichloroethenes (DCE) in gas samples is presented. The analytes are preconcentrated from a gas-volume of up to 20 l on an adsorption tube filled with 1.0 g of a carbon molecular sieve at a flow rate of 80 l/h and are subsequently desorbed with carbon disulfide. Vinyl bromide is added as internal standard to the extract. The analytes are determined as their 1,2-dibromo-derivatives by capillary gas chromatography with electron capture detection. The detection limits have been found to be 82 ng/m³ = 32 ppt (VC), 190 ng/m³ = 48 ppt (1,1-DCE) and 96 ng/m³ = 24 ppt (cis-/trans-1,2-DCE). The method has been used for the quantification of the anaerobic microbial degradation of tetra- (PCE) and trichloroethene (TCE) to dichloroethenes and vinyl chloride in landfill sites. The substances have been analyzed in landfill-gas as well as in gaseous emissions from the landfill surface. The mean emission rates of tetrachloroethene, trichloroethene and vinyl chloride from the landfill surface into the ambient air are about 0.5 g/(m² × h).     

1,3-Bis[2-(ethynyldimethylsilyl)vinyl]tetramethyldisiloxane and Macrocyclic Polyunsaturated Siloxanes on Its Basis

Hydrosilylation of diethynyldimethylsilane with tetramethyldisiloxane in the presence of chloroplatinic acid give rise to a mixture of three stereoisomers of 1,3-bis[2-(ethynyldimethylsilyl)vinyl]tetramethyldisiloxane: trans-trans, gem-trans, and gem-gem. Hydrolysis of chloro[2-(ethynyldimethylsilyl)vinyl]dimethylsilane provides the trans-trans isomer of 1,3-bis[2-(ethynyldimethylsilyl)vinyl]tetramethyldisiloxane exclusively. Reactions of an organomagnesium derivative of the disiloxane with dichlorodiorganylsilanes allowed synthesis of novel polyunsaturated macrocyclic siloxanes. The ¹H, ¹³C, and ²⁹Si NMR spectra of the products were studied.     

A selective GC column for trace analysis of vinyl chloride in air

Summary A selective GC column for the determination of vinyl chloride monomer in air has been developed. The 1.5m×1/8 column is filled with a mixture of Porapack S and T (8020). The selectivity was tested with 21 possible pollutants. All of the tested compounds were separated from vinyl chloride.     

Quaternary ammonium polyelectrolytes. IV. Addition reaction between poly(4-vinylpyridinium chloride) and electrophilic vinyl compounds

It was found that the addition reaction between poly(4-vinylpyridinium chloride) and electrophilic vinyl compounds, such as acrylic acid, acrylamide, methylacrylate, and acrylonitrile. leads to ammonium quaternary polymers with a transformation degree that depends oil the reactivity of vinyl compounds. The structure of addition compounds was established by using ¹H-NMR IR, and UV spectral methods. NMR-determined values of transformation degree indicate that the reactivity of vinyl compounds decreases as follows:      

Kinetics of ring-opening radical polymerization of vinyloxiranes

Ring-opening radical polymerization has been followed by the flash photolysis method. As an initiator radical, the arylthiyl radical (ArS^˙) was used; the addition reaction rate constants of ArS^˙ to vinyl monomer containing epoxy-ring such as vinyloxiranes have been determined at first. The rate constant of ring opening reaction of the adduct radical changing to ArSCH₂CH ? CROCH₂^˙ were determined in the form of the relative values, which were converted to the absolute values. The ring-opening reaction rate constants were ca. 10⁶ s^?1, which indicates that the ring-opening rates are faster than usual radical propagation rates. The rate constants for vinyl monomer with 5-member ring (1,4-epoxy-1,4-dihydronaphthalene) were similarly evaluated.     

Determination of unperturbed dimensions of polymers in binary solvent mixtures from viscosity measurements

Intrinsic viscosity measurements were carried out on poly(vinyl pyrrolidone) and poly(vinyl alcohol) in various solvents and solvent mixtures. The values of, [] andk, the latter two being the fundamental terms in the equationC/ _sp =1/kC, were utilized for the determination of the unperturbed dimensions in solution. The values of (¯r _o ² /M _w )^1/2 were calculated.