Dipolar Cycloaddition Of Azomethine Ylides Research Articles

Electrochemical characterization and estimation of DNA-binding capacity of a series of novel ferrocene derivatives

The synthesis of a series of methyl 2-alkyl-5-aryl-4-ferrocenoylpyrrolidine-2-carboxylates has been achieved by [3 + 2] dipolar cycloaddition of azomethine ylides to acryloylferrocene. The electrochemical properties of novel products were examined by cyclic voltammetry (CV) and differential pulse voltammetry (DPV). These techniques revealed the quasi-reversible one-electron oxidation process. The DNA-binding capacity of all the products was also studied using CV and DPV, and significant interactions between synthesized compounds and nucleic acid, mostly of the electrostatic type, were disclosed. DFT calculations and molecular docking tests were carried out to gain a more exhaustive insight into the interactions of the obtained products with nucleic acid. A detailed characterization of the new compounds was performed by IR, NMR and elemental analyses, followed by single-crystal X-ray diffraction experiments for two representatives.

Highly conductive functionalized reduced graphene oxide

Graphene oxide (GO) is a derivative of graphene that is formed by the exfoliation of graphite oxide; product of graphite treatment with strong oxidants [1–4]. GO nanosheets are decorated by epoxy and hydroxyl groups at the bulk and carboxylates mainly at the edges, while small isolated aromatic areas complete the surface [4–6]. The hydrophilic character of GO, due to the oxygen groups, induces high dispersibility in water or other polar solvents such as ethanol or dimethylformamide (DMF) [6,7]. On the other hand, due to the very low aromatic character, GO is practically non conductive. 1,3 dipolar cycloaddition of azomethine ylide on GO in DMF was followed by a simultaneous reduction of GO. The as prepared functionalized reduced graphene oxide showed excellent stability in water and high electrical conductivity.

Synthesis of novel multi-functionalized pyrrolidines by [3 + 2] dipolar cycloaddition of azomethine ylides and vinyl ketones

An efficient and easy synthetic route to substituted pyrrolidine derivatives has been established through [3 + 2] dipolar cycloaddition of vinyl ketones and azomethine ylides. The reactions proceed smoothly, under mild conditions, affording moderate to high isolated yields (up to 88%) of the products, within a short reaction time (15–45 min), providing a series of novel potentially bioactive compounds. Mechanistic considerations revealed that this cycloaddition exclusively proceeds following endo-pathway which enables access to the cis-derivatives. The products that contain acetyl group at C4 easily undergo isomerization, as it was confirmed by monitoring of the reaction kinetics and DFT calculations.

Asymmetric synthesis of polycyclic 3-fluoroalkylproline derivatives by intramolecular azomethine ylide cycloaddition

The asymmetric intramolecular dipolar cycloaddition of azomethine ylides was developed for fluorinated dipolarophiles, being the RF group crucial for selectivity.

Self-assembly of one-side-functionalized graphene nanosheets in bilayered superstructures for drug delivery

In this article, we describe the one-side functionalization of graphene nanosheets with hydrophilic catechol-bearing pyrrolidine rings. For this purpose, we used, for the first time, a solvothermal alternative of 1,3 dipolar cycloaddition of azomethine ylide. To achieve asymmetrical reaction, graphene nanosheets were initially and during reaction deposited on glass substrate. The result of one-side functionalization of graphene was the formation of amphiphilic few-layered graphene nanosheets. The modified side becomes hydrophilic due to the attachment of catechols, while the nonmodified side remains hydrophobic. In the literature, there are limited examples of functionalized graphene with different sides, the so-called Janus-type graphenes. These amphiphilic graphene nanosheets dispersed in water were self-organized in bilayer superstructures, with hydrophilic outer surface and hydrophobic internal space. The later can host hydrophobic molecules such as anticancer drugs and could be used in drug delivery systems. As an example, camptothecin, a drug practically insoluble in water, was used here to show that it can be transferred to water phase using graphene as transporter.

ChemInform Abstract: A Strategic Approach to the Synthesis of Novel Class of Dispiroheterocyclic Derivatives Through 1,3 Dipolar Cycloaddition of Azomethine Ylide with (E)‐3‐Arylidene‐2,3‐dihydro‐8‐nitro‐4‐quinolone.

Abstract A series of novel dispiroheterocyclic system containing 4-quinolone nucleus are prepared by 1,3 dipolar cycloaddition of azomethine ylides with a newly prepared (E)-3-arylidene-2,3-dihydro-8-nitro-4-quinolone as dipolarophile. The ylide was generated in situ from isatin and sarcosine/1,3-thiazolane-4-carboxylic acid. The regio and stereochemistry of the synthesized product was established by 1H, 13C, 2D NMR techniques and single crystal X-ray analysis. The molecular mechanism of this cycloaddition has been investigated by means of the density functional theory (DFT) method. The experimental results of regioselectivity product of 1,3 dipolar cycloaddition have shown good agreement with the computed Frontier molecular orbital calculation (FMO) and fukui function analysis.

A strategic approach to the synthesis of novel class of dispiroheterocyclic derivatives through 1,3 dipolar cycloaddition of azomethine ylide with (E)-3-arylidene-2,3-dihydro-8-nitro-4-quinolone

A series of novel dispiroheterocyclic system containing 4-quinolone nucleus are prepared by 1,3 dipolar cycloaddition of azomethine ylides with a newly prepared (E)-3-arylidene-2,3-dihydro-8-nitro-4-quinolone as dipolarophile. The ylide was generated in situ from isatin and sarcosine/1,3-thiazolane-4-carboxylic acid. The regio and stereochemistry of the synthesized product was established by 1H, 13C, 2D NMR techniques and single crystal X-ray analysis. The molecular mechanism of this cycloaddition has been investigated by means of the density functional theory (DFT) method. The experimental results of regioselectivity product of 1,3 dipolar cycloaddition have shown good agreement with the computed Frontier molecular orbital calculation (FMO) and fukui function analysis.

Cooperative behavior in functionalized graphene: Explaining the occurrence of 1,3 cycloaddition of azomethine ylides onto graphene

Cycloaddition reactions onto graphene were studied by means of first-principle calculations. We found that for all reactions studied there is a cooperative behavior responsible for dramatically increasing the reaction energies. This result explains the reason why the 1,3 dipolar cycloaddition of azomethine ylides is both feasible and slow. The cooperative effect decreases in the following order: [2+2]-addition of benzynes >1,3-dipolar cycloaddition >[2+1]-cycloaddition of NH. This cooperative behavior can open new avenues to fine-tune the physical and chemical properties of graphene. Our results indicate that it is possible to fine tune the band gap of graphene from 0 to 2eV by varying the number of azomethine groups attached.

ChemInform Abstract: Auxiliary‐Controlled Asymmetric [3 + 2]‐Dipolar Cycloaddition of Azomethine Ylides Generated from Au‐Catalyzed Intramolecular Redox Reaction of Nitronyl Alkynes.

AbstractThe (S)‐α‐methyl‐p‐nitrobenzyl moiety is found to be a removable auxiliary for the title intramolecular reaction by controlling the C—N rotation and thus providing a wide variety of azabicyclo[3.2.1]octane derivatives with excellent diastereoselectivity.

Auxiliary‐Controlled Asymmetric [3+2]‐Dipolar Cycloaddition of Azomethine Ylides Generated from Au‐Catalyzed Intramolecular Redox Reaction of Nitronyl Alkynes

The (S)-α-methyl-p-nitrobenzyl moiety is found to be a removable auxiliary for the title intramolecular reaction by controlling the C—N rotation and thus providing a wide variety of azabicyclo[3.2.1]octane derivatives with excellent diastereoselectivity.

Chemical Functionalization of Ultrathin Carbon Nanosheets

Ultrathin carbon nanosheets (CNSs) were functionalized using 1,3 dipolar cycloaddition of azomethine ylide. The organic modification of carbon nanosheets with hydroxyl groups on the external graphene layers facilitates the dispersion in polar solvents including water and thus the incorporation of the derivatives in other matrices such as polymers.

Organic functionalisation of graphenes

Graphene sheets derived from dispersion of graphite in pyridine were functionalised by the 1,3 dipolar cycloaddition of azomethine ylide. The organically modified graphene sheets are easily dispersible in polar organic solvents and water, and they are extensively characterised using several spectroscopic and microscopy techniques.

The 1,3 dipolar cycloaddition of azomethine ylides to graphene, single wall carbon nanotubes, and C60

AbstractHerein, we perform a comparative study on the addition of azomethine ylides to graphene, carbon nanotubes, C60, ethene, pyrene and a C48H18 hydrocarbon. The calculated binding energies and free energy corrections suggest that the addition of azomethine ylide to perfect graphene is not spontaneous (ΔG > 0). However, the presence of Stones–Wales defects significantly increases reactivity: the binding energy between SW‐defective graphene and the azomethine ylide is 0.83 eV, close to that determined for a (5,5) SWCNT. The electronic properties of the sheet are not modified by the 1,3 cycloaddition. The binding energies determined for the addition of an azomethine ylide to a (5,5) SWCNT are significantly lower than previously reported. © 2009 Wiley Periodicals, Inc. Int J Quantum Chem, 2010

The First Organocatalytic Enantio- and Diastereoselective 1,3-Dipolar Cycloaddition of Azomethine Ylides with Nitroalkenes

The first chiral thiourea-catalyzed stereoselective 1,3- dipolar cycloaddition of azomethine ylides with nitroalkenes afforded highly substituted pyrrolidines with high diastereoselectivities of up to <99:1 dr and moderate enantioselectivities.

Synthesis of tetracyclic indole-containing ring systems by intramolecular cycloadditions of azomethine ylides

Dipolar cycloaddition of azomethine ylides derived from addition of amines to a 2-butenylindole-3-carboxaldehyde provides a stereoselective synthesis of tetracyclic products present in a variety of indole alkaloids. The chemistry was applied to a formal synthesis of the iboga alkaloid deethylibophyllidine.

Solid-Phase Pyrrolidine Synthesis via 1,3- Dipolar Cycloaddition of Azomethine Ylides Generated by the Decarboxylative Route

Although solid-phase pyrrolidine synthesis via dipolar cycloaddition of ester-stabilized azomethine ylides has been demonstrated on several occasions, this reaction with nonstabilized azomethine ylides, generated on solid support by a decarboxylative pathway, has never been reported. Herein we present the first solid-phase synthesis of pyrrolidines via this route and demonstrate that the reacting azomethine ylide can be generated both from a resin-bound aldehyde or amino acid. Using cyclic and acyclic dipolarophiles, bi- and monocyclic resin-bound pyrrolidines were obtained. The modest to high degree of regio-and diastereoselectivity observed in the reaction can be tuned by the substituents of the partners of this three-component process.

The Addition of Azomethine Ylides to [60]Fullerene Leading to Fulleropyrrolidines

AbstractFor Abstract see ChemInform Abstract in Full Text.

The Addition of AzomethineYlides to [60]Fullerene Leading to Fulleropyrrolidines

This account reports recent developments in the synthesis of fulleropyrrolidines, prepared via 1,3 dipolar cycloaddition of azomethine ylides to fullerenes. The versatility of this approach makes fulleropyrrolidines an attractive target to an interdisciplinary community of researchers. In addition, the fullerene derivatives are more soluble in polar solvents, so that they can self-assemble in complex supramolecular architectures or form novel hybrid systems with potential applications in biological and technological areas.

A New Synthesis of 3,5-Diaryl-pyrrole-2-carboxylic Acids and Esters

A new two-step synthesis of pyrrole-2-carboxylic acids, steps via 1,3 dipolar cycloaddition of azomethine ylides to nitro-styrenes and oxidation of the resulting pyrrolidines with alkaline hydrogen peroxide is described. The oxidation of cycloadducts 3 by the means of MnO 2 under different conditions also has been examined.

A New Synthesis of Pyrrole-2-Carboxylic Acids

A new two-step synthesis of pyrrole-2-carboxylic acids is described, steps via 1,3 dipolar cycloaddition of azomethine ylides to nitro-styrenes and oxidation of the resulting pyrrolidines with alkaline hydrogen peroxide.