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Fundulea, Romania

Popa M.M.,Romanian Academy of Sciences | Popa M.M.,Polytechnic University of Bucharest | Georgescu E.,Research Center Oltchim | Draghici C.,Romanian Academy of Sciences | And 3 more authors.
Monatshefte fur Chemie | Year: 2015

A variety of new pyrrolo-fused heterocyclic systems bearing a 3-carbonylchromen-2-one moiety on the pyrrole rings was obtained based on 1,3-dipolar cycloaddition reactions of corresponding cycloimmonium-ylides, generated in situ from the quaternary salts of several N-heterocycles with 3-(2-bromoacetyl)-2H-chromen-2-one, with electron-deficient alkynes. The synthetic strategies were both one-pot, three-component and classical multistep 1,3-dipolar cycloaddition reactions. The all newly synthesized compounds were structurally characterized by elemental analysis, IR and NMR spectroscopy. Graphical abstract: [Figure not available: see fulltext.] © 2015 Springer-Verlag Wien.


Popa M.M.,Center For Organic Chemistry Cd Nenitzescu | Popa M.M.,Polytechnic University of Bucharest | Georgescu E.,Research Center Oltchim | Caira M.R.,University of Cape Town | And 5 more authors.
Beilstein Journal of Organic Chemistry | Year: 2015

The three possible structural isomers of 4-(pyridyl)pyrimidine were employed for the synthesis of new pyrrolo[1,2-c]pyrimidines and new indolizines, by 1,3-dipolar cycloaddition reaction of their corresponding N-ylides generated in situ from their corresponding cycloimmonium bromides. In the case of 4-(3-pyridyl)pyrimidine and 4-(4-pyridyl)pyrimidine the quaternization reactions occur as expected at the pyridine nitrogen atom leading to pyridinium bromides and consequently to new indolizines via the corresponding pyridinium N-ylides. However, in the case of 4-(2-pyridyl)pyrimidine the steric hindrance directs the reaction to the pyrimidinium N-ylides and, subsequently, to the formation of the pyrrolo[1,2-c]pyrimidines. The new pyrrolo[1,2-c]pyrimidines and the new indolizines were structurally characterized through NMR spectroscopy. The X-ray structures of two of the starting materials, 4-(2-pyridyl)pyrimidine and 4-(4-pyridyl)pyrimidine, are also reported. © 2015 Popa et al.


Georgescu E.,Research Center Oltchim | Nicolescu A.,Petru Poni Institute of Macromolecular Chemistry | Georgescu F.,Teso Spec SRL | Shova S.,Petru Poni Institute of Macromolecular Chemistry | And 3 more authors.
Synthesis (Germany) | Year: 2015

Abstract A simple one-pot multicomponent procedure has been developed for the synthesis of pyrrolo[1,2-a]benzimidazole and pyrrolo[1,2-a]quinoxaline derivatives by heating a 1:2:1 molar mixture of a benzimidazole unsubstituted on the imidazole ring, a 2-bromoacetophenone derivative, and a nonsymmetrical activated alkyne in refluxing 2-ethyloxirane. The reaction can be performed under conventional reflux conditions or with microwave irradiation. © Georg Thieme Verlag.


Georgescu E.,Research Center Oltchim | Nicolescu A.,Romanian Academy of Sciences | Nicolescu A.,Petru Poni Institute of Macromolecular Chemistry | Georgescu F.,Teso Spec SRL | And 5 more authors.
Beilstein Journal of Organic Chemistry | Year: 2014

The one-pot three-component reactions of 1-substituted benzimidazoles with ethyl bromoacetate and electron-deficient alkynes, in 1,2-epoxybutane, gave a variety of pyrrolo[1,2-a]quinoxalin-4-ones and pyrrolo[1,2-a]benzimidazoles. The influence of experimental conditions on the course of reaction was investigated. A novel synthetic pathway starting from benzimidazoles unsubstituted at the five membered ring, alkyl bromoacetates and non-symmetrical electron-deficient alkynes in the molar ratio of 1:2:1, in 1,2-epoxybutane at reflux temperature, led directly to pyrrolo[1,2-a]quinoxalin-4-ones in fair yield by an one-pot threecomponent reaction. © 2014 Georgescu et al.

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