microstructural investigation of low molecular weight 1,4-polybutadiene (1,4-pbd) was studied by 1h and 13c nuclear magnetic resonance spectroscopy (nmr). the isomer contents of 1,4-cis, 1,4-trans and 1,2- vinyl in polybutadiene microstructure were determined. the number average molecular weight for low molecular weight polybutadiene was measured by nmr techniques and comparison was made with g...

Abstract While vinyl cyclopropanes are valuable functional groups in drugs or natural products as well established precursors to trigger a rich variety of synthetic transformations, their reactive nature can make installation via direct catalytic approaches challenging. We herein present modular access (di)vinyl under very mild conditions and full conservation stereochemistry, allowing the cis ...

route to vinyl epoxides and vinyl aziridines via chiral sulfur ylides, we were keen to develop their potential in synthesis further. It had been reported that palladium-catalyzed reactions of vinyl epoxides and aziridines with doubly activated Michael acceptors gave tetrahydrofurans and pyrrolidines in good yield but usually with poor stereocontrol. However, related reactions with singly activa...

 In this research of cis, trans and vinyl monomeric derivatives of 1,4-butadiene were studied using C20 in different temperatures by Functional density theory (DFT). To this purpose, the materials were firstly optimized geometrically, then the calculations of the thermodynamic parameters were performed on all of them. In the following, changes in parameters of energy...

The title compound, C(21)H(18)O(3)S, is the E isomer, the ester -oxy link being trans to one of the phenyl groups. The planes of the phenyl substituents at the vinyl C atoms form a dihedral angle of 66.32 (7)° with each other. The vinyl group shows noticeable non-planarity, the C(Ph)-C=C-C(Ph) torsion angle being 8.4 (3)°.

In the title compound, trans-[RhCl(C(20)H(17)P)(2)(CO)], the Rh(I) atom is situated on a center of symmetry, resulting in a statistical 1:1 disorder of the chloride [Rh-Cl = 2.383 (2) Å] and carbonyl [Rh-C = 1.752 (7) Å] ligands. The distorted trans square-planar environment is completed by two P atoms [Rh-P = 2.3251 (4) Å] from two diphen-yl(4-vinyl-phen-yl)phosphane ligands. The vinyl group i...

Brønsted acid promoted reversible dimerization of myrmicarin 215B leads to formation of a new heptacyclic product, isomyrmicarin 430B, that possesses a C1,C2-trans,C2,C3-trans-substituted cyclopentane ring. Mechanistic studies illustrate that isomyrmicarin 430B arises by isomerization of isomyrmicarin 430A via fragmentation to tricyclic azafulvenium ions. Factors influencing the structure of he...

Electrocyclic ring opening of 4,6-fused cyclobutenamides 1 under thermal conditions leads to cis,trans-cyclooctadienones 2-E,E as transient intermediates, en route to 5,5-bicyclic products 3. Theoretical calculations predict that 4,5-fused cyclobutenamides should likewise undergo thermal ring opening, giving cis,trans-cycloheptadienones, but in this case conversion to 5,4-bicyclic products is t...

A novel series of (3-diethoxyphosphoryl)isoxazolidines substituted at C5 with various quinazolinones have been synthesized by the 1,3-dipolar cycloaddition of N-methyl-C-(diethoxyphosphoryl)nitrone with N3-substitued 2-vinyl-3H-quinazolin-4-ones. All isoxazolidines were assessed for antiviral activity against a broad range of DNA and RNA viruses. Isoxazolidines trans-11f/cis-11f (90:10), trans-...

The synthesis and characterization of the precursor isomers trans-4-(2-(pyridin-2-yl)vinylbenzaldehyde (I), trans-4-(2-(pyridin-4-yl)vinylbenzaldehyde (II), trans-4-(2-(pyridin-2-yl)vinylbenzoic acid (III) and (E)-4-(2-(pydridin-4-yl)vinylbenzoic acid (IV) are reported. These compounds were prepared in order to obtain trans-4-((E)-2-(pyridin-2-yl)vinyl)benzamide-TEMPO (V). Compounds I and II we...