Pyridinium Dicyanomethylides Research Articles

Unveiling [3 + 2] cycloaddition reactions of pyridinium bis(methoxycarbonyl)methylides and pyridinium dicyanomethylides with cyclooctyne for indolizine synthesis from the molecular electron density theory perspective

Unveiling [3 + 2] cycloaddition reactions of pyridinium bis(methoxycarbonyl)methylides and pyridinium dicyanomethylides with cyclooctyne for indolizine synthesis from the molecular electron density theory perspective

ChemInform Abstract: Heterocyclic Anellated Indolizines from Intramolecular (3 + 2) Cycloaddition with Pyridinium Dicyanomethylides.

ChemInform Abstract: Heterocyclic Anellated Indolizines from Intramolecular (3 + 2) Cycloaddition with Pyridinium Dicyanomethylides.

1,3‐Dipolar Cycloaddition of Ethyl 2,3‐Pentadienoate with Pyridinium Dicyanomethylides: Regiospecific Formation of Ethyl 3‐Cyano‐2‐ethylindolizine‐1‐carboxylates and a Novel Formation of Tricyclic Compounds.

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.

Aspects of three-electron two-centre, four-electron three-centre and six-electron five-centre bonding in cycloimmonium ylides

Abstract The weights for several types of local valence bond structures which are involved in two-electron two-centre, three-electron two-centre and four-electron three-centre bonding units for the π-electrons of pyridinium dicyanomethylide are calculated via a Poly-Electron Population Analysis of a Hartree–Fock MO wavefunction. It is shown that three-electron two-centre and four-electron three-centre behavior for the ylide bond is better developed towards the substituents of the ylide carbon atom, rather than the pyridinium group; this gives rise to a polarized increased-valence bonding, which is the principal specificity of cycloimmonium ylides. Qualitative consideration is given to six-electron five-centre bonding units for the π-electrons.

1,3-Dipolar Cycloaddition of Ethyl 2,3-Pentadienoate with Pyridinium Dicyanomethylides: Regiospecific Formation of Ethyl 3-Cyano-2-ethylindolizine-1-carboxylates and a Novel Formation of Tricyclic Compounds

Pyridinium dicyanomethylides underwent site- and regioslective 1,3-dipolar cycloaddition with ethyl 2,3-pentadienoate to give ethyl 3-cyano-2-ethylindolizine-1-carboxylates in moderate yields. In two cases, a novel type of the tricycle compounds, in addition to indolizines, were obtained whose structure was established by a single crystal X-Ray analysis. A plausible mechanism for its formation is also presented.

Three‐electron two‐center bonding in cycloimmonium ylides

AbstractWe explore the possibility that a 3‐electron‐2‐center bonding exists in cycloimmonium ylides. To detect this bonding in a polyatomic system, 3‐electron‐1‐hole density operators, characterizing a Pauling 3‐electron bond, are used in the framework of second quantization formalism. The weights of 3‐electron resonance structures are calculated and compared with the weights of 2‐electron structures for the ylide bond of pyridinium dicyanomethylide; the correlations of (↑↓) and (↑) electronic events, involved in the 3‐electron resonance structures, are also investigated. The calculations are performed in various approximation levels, and both orthogonal and nonorthogonal natural atomic orbitals are adopted. All calculations show that a 3‐electron bond exists between N and C atoms of ylide bond, but this bonding is not extended in C atoms of the pyridinium group. The interactions of α,β electrons (at the configuration interaction [CI] level) increase the localization of electrons, the weights of 3‐electron resonance structures, and thus the probability for 3‐electron bonding. © 2004 Wiley Periodicals, Inc. Int J Quantum Chem, 2004

Inverse electron‐demand 1,3‐dipolar cycloaddition reactions of cyclooctyne with pyridinium bis(methoxycarbonyl)methylides

AbstractCyclooctyne underwent 1,3‐dipolar cycloaddition with pyridinium bis(methoxy‐carbonyl)methylides to afford the corresponding indolizines (8‐methoxycarbonyl‐7‐azatricyclo[7.6.0.02‐7]pentadeca‐1,3,5,8‐tetraenes) in good to moderate yields. Some molecular orbital considerations are also described on this reaction compared with the results on the reaction of pyridinium dicyanomethylides with cyclooctyne.

1,3-Dipolar Cycloaddition of 1-Phenylpropa-1,2-diene with Pyridinium Dicyanomethylides: 1-Phenylpropa-1,2-diene as a Synthetic Equivalent of 1-Phenylpropyne

1,3-Dipolar Cycloaddition of 1-Phenylpropa-1,2-diene with Pyridinium Dicyanomethylides: 1-Phenylpropa-1,2-diene as a Synthetic Equivalent of 1-Phenylpropyne

Experimental and ab initio MO studies on the IR spectra and structure of pyridinium dicyanomethylide and trimethylammonium dicyanomethylide

The structures of the title ylides have been studied by both quantitative infrared (IR) spectra and ab initio HF and MP2 force field calculations. Good agreement has been found between theoretical and experimental data for their spectral and structural characteristics. According to both IR data and geometry parameters the dicyanomethide groups in the ylides studied have a pronounced carbanionic character. The analysis of the calculated net electric charges however shows only moderate (below 0.6 e-) intramolecular charge transfers between the pyridinium (trimethylammonium) and dicyanomethide fragments of the species studied.

ChemInform Abstract: Correlation of 13C‐ and 15‐NMR Chemical Shifts of Ylidic Carbon and Nitrogen with Calculated Partial Charges in Pyridinium Dicyanomethylides.

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

Reactions of Tetracyanoethylene Oxide (TCNEO) with Cobaltadithiolene Complexes

Abstract The reactions of cobaltadithiolene complexes bearing phenyl or ester ligands with tetracyanoethylene oxide (TCNEO) result in the formation of dicyanomethylene-bridged complexes, via dicyanomethylide intermediates. Furthermore, the reaction of cobaltadithiolene complex bearing 4-pyridyl ligands produces pyridinium dicyanomethylide complexes in good yields.

ChemInform Abstract: Formation of 1,2,3,4‐Dibenzocycl(2.2.3)azines (III) by a Novel Consecutive 1,3‐Dipolar Cycloaddition of Pyridinium Dicyanomethylides to Benzyne.

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

Correlation of 13C- and 15N-NMR Chemical Shifts of Ylidic Carbon and Nitrogen with Calculated Partial Charges in Pyridinium Dicyanomethylides

Correlation of 13C- and 15N-NMR Chemical Shifts of Ylidic Carbon and Nitrogen with Calculated Partial Charges in Pyridinium Dicyanomethylides

1,3‐Dipolar cycloaddition reactions of cyclooctyne with pyridinium dicynomethylides

AbstractCyclooctyne smoothly underwent 1,3‐dipolar cycloaddition with pyridinium dicyanomethylides to afford the corresponding indolizines (8‐cyario‐7‐azatricyclo[7.6.0.02,7]pentadeca‐1,3,5,8‐tetraenes) in excellent yields.

Formation of 1,2,3,4-dibenzocycl[2.2.3]azines by a novel consecutive 1,3-dipolar cycloaddition of pyridinium dicyanomethylides to benzyne

A one-pot procedure for the direct and surprisingly simple formation of the title compounds by the reactions of pyridinium dicyanomethylides with benzyne are described together with full details of the 1H and 13C NMR data for the products.

Effect of Incomplete d Orbital on the Epoxy Resins Properties: Synthesis and Characterization

Abstract The theoretical generalization of the experimental results, to investigate the effect of incomplete d orbital, using nickel acrylate (NiA2) on the epoxy resins properties is repoted. The value(s) of epoxide equivalent, hydroxyl content, hydrolyzable chlorine content, specific gravity, refractive index of epoxy resins have been evaluated. DSC data have been used to determine the order of reaction, heat of reaction, activation energy & glass transition temperature (Tg). The epoxy resins, cured with pyridinium dicyano methylide (PDMY), as a new curing agent, showed improved chemical resistance, flexibility and electrical conductivity.

Solvatochromic studies of interactions between surfactants and poly( N-substituted acrylamide)s

Abstract Interactions between poly(N-substituted acrylamide)s and surfactants, such as sodium dodecyl sulfate (SDoS) and sodium decyl sulfate (SDeS), in aqueous solutions were investigated using a solvatochromic probe. The polymers used were poly(N,N-dimethylacrylamide) (PDMA), poly(N-isopropylacrylamide) (PIPA), poly(N-acryloylpyrrolidine) (PAPR), and poly(vinylpyrrolidone) (PVPy) for comparison. They were labeled with pyridinium dicyanomethylide chromophore as a solvatochromic probe, and the changes in the microenvironment polarity of the polymer upon association with surfactant micelles were investigated by monitoring the λmax in the absorption spectra of the probe molecule. It was found that the Gibbs free energy of micelle stabilization by polymer complexation for SDoS is 7.6, 4.1, and 2.2 kJ mol−1, and for SDeS 5.1, 2.9, and 0.8 kJ mol−1 with PIPA, PAPR, and PDMA, respectively. These results indicate that the complexation between polymer and surfactant is influenced not only by the alkyl-chain length of the surfactant, but also by the polymer side groups.

Solvatochromic probes for the investigation of polymer—micelle interactions

Interactions between poly(N-acryloylpyrrolidine) (PAPR) and surfactants such as sodium dodecyl sulfate, sodium decyl sulfate, and dodecyltrimethylammonium bromide in aqueous solutions have been investigated through the use of solvatochromic probes. The polymer was labeled with pyridinium dicyanomethylide chromophore as a solvatochromic probe, and the changes in the microenvironment polarity of the polymer upon association with the micelles were investigated by monitoring the λmax in absorption spectra of the probe molecule. It was found that, in the presence of the anionic surfactant micelles, λmax of the labeled polymer was shifted to longer wavelength while no shift was observed in λmax in the presence of the cationic surfactant. These results imply that PAPR associates strongly with anionic surfactants but negligibly with cationic surfactants.

Pyridinium Dicyanomethylide Initiated Copolymerization of Styrene and Methyl Methacrylate

Cinetique de la copolymerisation radicalaire amorcee par l'ylure. On obtient un copolymere alterne meme en l'absence d'un acide de Lewis, caracterise par RMN 1 H

ChemInform Abstract: Synthesis and Reactions of 1,2‐Fused 3‐Cyanoindolizines.

AbstractThe pyridinium dicyanomethylides (I) react with dehydrobenzene, generated from diphenyliodonium 2‐carboxylate (II), to give the indolizines (III) mentioned in the title, together with minor amounts of the pentacycles (IV).