Cycloaddition Reaction Of Azomethine Ylides Research Articles

Halochromism of pyridinium azomethine ylides stabilized by dicyanopyrazine group

Reactions of 2-bromomethyl-3-phenyl-5,6-dicyanopyrazine with methyl substituted pyridine gave dicyanopyrazylmethylene pyridinium bromides. These salts were changed to their corresponding methylides by the addition of a base, which were restored by the addition of an acid. The pyridinium methylides exhibited intense visible absorption. This study was attempted to apply the pyridinium halides with a dicyanopyrazine group to a reversibly colored material to gain an external response. The 1,3-dipolar cycloaddition reaction of such pyridinium azomethine ylides containing a stabilized dicyanopyrazine group with dimethyl acetylenedicarboxylate (DMAD) afforded the indolizine derivatives.

Synthesis of [60]fullerene–coumarin polyads

New polyads were obtained by covalently linking a coumarin dye to a fullerene (C 60) following two different strategies: 1,3-dipolar cycloaddition reaction of azomethine ylides or by cyclopropanation reaction. The new polyads are spectroscopically characterized and their fluorescence properties, including the observation of efficient singlet–singlet energy transfer, reported.

One-pot highly diastereoselective synthesis of some novel spiro pyrrolizidines via 1,3-dipolar cycloaddition reaction of azomethine ylide

Indenoquinoxaline-11-one derivatives react with proline and N-aryl maleimides via decarboxylative azomethine ylide formation and subsequent 1,3-dipolar cycloaddition involving an exo- transition state to give new heterocyclic adducts in 71–94% yields.

1,3‐Dipolar Cycloaddition Reactions of Pyridinium Azomethine Ylides Containing 5,6‐Dicyanopyrazines.

AbstractFor Abstract see ChemInform Abstract in Full Text.

60]Fullerene–flavonoid dyads

A range of fullerene–chalcone, fullerene–flavone, and fullerene–chromone dyads, including a bis(flavonyl)-fullerene dyad, were prepared by 1,3-dipolar cycloaddition reactions of azomethine ylides to C 60 and by cyclopropanation of C 60 with flavonyl malonates. Synthetic and natural flavonoid derivatives were used as starting materials.

A New Access to Dispiro 7‐Oxaindazolidines Spiroxindole Derivatives.

AbstractFor Abstract see ChemInform Abstract in Full Text.

The Huisgen Reaction of Azomethine Ylide to Isatins: A Facile Synthesis of Spiro-oxindoles

A facile and convenient synthesis of spiro-oxindoles, structural units of many bioactive natural products, via 1,3-dipolar cycloaddition reaction of azomethine ylide with isatins is described.

A New Access to Dispiro 7-Oxaindazolidines Spiroxindole Derivatives

Synthesis of dispiro 7-oxaindazolidines has been accomplished by regioselective 1,3-dipoiar cycloaddition reaction of azomethine ylide generated from secondary amine, morpholine, and isatin (via deprotonation route) with arylidene chromanones and arylidene tetralones as dipolarophiles.

Synthetic enantiopure aziridinomitosenes: preparation, reactivity, and DNA alkylation studies.

An enantiocontrolled route to aziridinomitosenes had been developed from l-serine methyl ester hydrochloride. The tetracyclic target ring system was assembled by an internal azomethine ylide cycloaddition reaction based on silver ion-assisted intramolecular oxazole alkylation and cyanide-induced ylide generation via a labile oxazoline intermediate (62 to 66). Other key steps include reductive detritylation of 26, methylation of the N-H aziridine 56, oxidation of the sensitive cyclohexenedione 68 to quinone 70, and carbamoylation using Fmoc-NCO. Although the aziridinomitosene tetracycle is sensitive, a range of protecting group manipulations and redox chemistry can be performed if suitable precautions are taken. A study of DNA alkylation by the first C-6,C-7-unsubstituted aziridinomitosene 11a has been carried out, and evidence for DNA cross-link formation involving nucleophilic addition to the quinone subunit is described.

1,3-Dipolar Cycloaddition Reactions of Pyridinium Azomethine Ylides Containing 5,6-Dicyanopyrazines

The intermolecular 1,3-dipolar cycloaddition reaction of azomethine ylides with carbon-carbon double or triple bonds represents an efficient and convergent method for the construction of heterocyclic structures containing a single nitrogen atom. 1 One of the most frequently employed methods for the generation of azomethine ylide involves the thermolysis of an aziridine. 2 However, the ring opening of aziridines to azomethine ylides is limited to those having substituent groups capable of stabilizing the dipole centers. Desilylation of α-trimethylsilylonium salts represents another convenient method of generating azomethine ylide. 3 More recently it has been found that nonstabilized azomethine ylides can be generated by the deprotonation of amine Noxides. 4 Azomethine ylides are too unstable to be isolated, and are typically used in situ. Of the various types of azomethine ylides, the pyridinium azomethine ylides are among the most attractive synthetically because they are easily prepared from the appropriate N-alkylpyridinium salt with base and their cycloadducts, the indolizines, have been used as synthetic building blocks. 5 In our continuing efforts to develop functional dyes based on dicyanopyrazine chromophores, we have become interested in pyridinium azomethine ylides containing dicyanopyrazines and their 1,3-dipolar cycloaddition reaction with dipolarophiles, because the indolizine cycloadducts, containing dicyanopyrazines, might meet our purpose. Dyes and pigments generally possess satisfactory color, and good color fastness properties against light and heat, and additional properties such as near infrared absorption, pleochroism, and photoconductivity. 6 The majority of these properties are caused by intramolecular charge-transfer interactions involving π-electrons and intermolecular π-π interactions of the dye chromophores. 7 In this paper, we report the generation of pyridinium azomethine ylide intermediates and the results of 1,3-dipolar cycloaddition reactions of the ylides with dipolarophiles to provide indolizines containing 5,6-dicyanopyrazine. The preparation of methyl or phenyl substituted 2-bromomethyl5,6-dicyanopyrazine 1 is described in a previous report. 6b

Microwave-assisted [3 + 2] cycloadditions of azomethine ylides.

The microwave-assisted intramolecular [3 + 2] cycloaddition reaction of azomethine ylides to activated and nonactivated alkenes and alkynes is described. The procedure allows the synthesis of pyrrolidines and pyrrole products in good to excellent overall yields in short reaction times. It appears from parallel comparative studies that the microwave procedure favors the reaction times and overall purity of the crude reaction mixture. The reactions can also be performed in the absence of solvent. [reaction: see text]

A Novel Entry into a New Class of Dispiroheterocycles Through Azomethine Ylides Involving Unusual Dipolarophiles.

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A High Regioselective Synthesis of Novel Dispiro[oxindole‐cyclohexanone]pyrrolidines.

AbstractFor Abstract see ChemInform Abstract in Full Text.

Catalytic Asymmetric 1,3‐Dipolar Cycloaddition Reactions of Azomethine Ylides — A Simple Approach to Optically Active Highly Functionalized Proline Derivatives.

Catalytic Asymmetric 1,3‐Dipolar Cycloaddition Reactions of Azomethine Ylides — A Simple Approach to Optically Active Highly Functionalized Proline Derivatives.

The Synthesis of Spirooxindole Pyrrolidines via an Asymmetric Azomethine Ylide [1,3]‐Dipolar Cycloaddition Reaction.

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Flavindogenides as 2π Component in 1,3‐Dipolar Cycloaddition Reaction — An Efficient Synthesis of New Class of Dispiroheterocycles.

AbstractFor Abstract see ChemInform Abstract in Full Text.

A High Regioselective Synthesis of Novel Dispiro[oxindole-cyclohexanone]pyrrolidines

A simple and efficient synthesis of title compounds has been accomplished by regioselective 1,3-dipolar cycloaddition reaction of azomethine ylide generated by the decarboxylative condensation of isatin and sarcosine with (E)-2-arylidene-1-cyclohexanones. The regio and stereochemistry of products were determined by spectroscopic techniques. The synthesis proceeds in good yield to afford a series of novel dispiro[oxindole-cyclohexanone]pyrrolidines, 1-N-methyl-spiro-[2.31]oxindole-spiro[3.211]111-cyclohexanone-4-aryl-pyrrolidines.

A Novel Entry into a New Class of Dispiroheterocycles Through Azomethine Ylides Involving Unusual Dipolarophiles

The cycloaddition reaction of azomethine ylides towards (E)-3-arylidene-4-chromanone as new dipolarophile has been investigated. High degree of regioselectivity has been observed in the synthesis of a new class of functionalized dispiroheterocyclic pyrrolidines bearing chromanone and acenaphthenequinone framework.

Synthesis, Antimicrobial and Antifungal Activity of a New Class of Spiro pyrrolidines

A new class of spiro pyrrolidines, dispiro[oxindole-cyclohexanone]pyrrolidines, 1 dispiro[oxindole-tetrahydronaphthalen-1-one]pyrrolidines, 2 dispiro[oxindole-arylidene-cyclohexanone]pyrrolidines, 3 dispiro[oxindole-hexahydro-indazole]pyrrolidines, 3 and spiro[butenolide]pyrrolidines, 4 have been screened for their antibacterial and antifungal activity against ten human pathogenic bacteria and four dermatophytic fungi. They were found to have antimicrobial and antifungal activity compounds against various pathogens except Bacillus subtilis. The spiro pyrrolidinines were synthesized by the regioselective 1,3-dipolar cycloaddition reaction of azomethine ylides generated either from isatin and sarcosine or from aziridine. The azomethine ylide so generated reacted with various dipolarophiles such as 2-arylidene-cyclohexanones, 2-arylidene-tetrahydronapthalen-1-ones, 2,6-bis(arylmethylidene)cyclohexanones and 3-arylidene-5-phenyl- butenolides.

Catalytic asymmetric 1,3-dipolar cycloaddition reactions of azomethine ylides-a simple approach to optically active highly functionalized proline derivatives.

Catalytic asymmetric 1,3-dipolar cycloaddition reactions of azomethine ylides-a simple approach to optically active highly functionalized proline derivatives.