Enamines with isobenzofuroxan: a novel synthesis of quinoxaline-di-n-oxides

Haddadin, Makhluf J.; Issidorides, Costas H.

doi:10.1016/s0040-4039(01)89222-4

Cited by 59 publications

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“…[118][119]. An elegant one-step synthesis of QdNO's, which comprised the reaction of variously substituted benzofurazan 1-oxide (BFO's) with enamines or enolate anions, was reported in 1965 by Haddadin and Issidorides [120][121]. With this method a wide variety of QdNO's were prepared in good yields.…”

Section: Anti-protozoal and Anti-candida Activitiesmentioning

confidence: 99%

Quinoxaline 1,4-Dioxide: A Versatile Scaffold Endowed With Manifold Activities

Carta

Corona²,

Loriga

2005

CMC

136

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Since 1940s, Quinoxaline 1,4-dioxides (QdNO's) are known as potent antibacterial agents, and subtherapeutic levels have been used to promote growth and improve efficiency of feed conversion in animal feed. They have also shown a selective cytotoxicity against hypoxic cells present in solid tumours. Furthermore, recent studies have put in evidence that QdNO's are endowed with antitubercular, antiprotozoal and anticandida activities. On the other hand, several authors have reported about photoallergic and mutagenic effects of some derivatives. QdNO's may also cause the development of antibiotic-resistant bacteria and influence the horizontal transfer of virulence genes between bacteria. In this review article we report the biological properties, the mode of action and Structure Activity Relationship (SAR) studies of the QdNO derivatives. Furthermore, some cytogenetic and genotoxic effects, classical and more recent method of synthesis, the quinoxaline 1,4-dioxides, and some of their most important reactions, were also reported.

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Section: Anti-protozoal and Anti-candida Activitiesmentioning

confidence: 99%

Quinoxaline 1,4-Dioxide: A Versatile Scaffold Endowed With Manifold Activities

Carta

Corona²,

Loriga

2005

CMC

136

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“…However, contrary to the condensation of benzofurazan oxide (12) with enamines, the use of β-keto-esters in a basic medium give quinoxaline di-N-oxide in low yields. For instance, the preparation of 2-methyl-3-carNov-Dec 2005 1381 Vol.…”

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confidence: 92%

“…These results appear to indicate that the condensation step was influenced by the electronic profile of the β-keto-ester because significant differences were found upon comparing the condensation of 12 with that of ethyl-(4-nitrobenzoyl)acetate (σ p = 0.81) and with that of ethyl-(4-methoxylbenzoyl) acetate (σ p = -0.28)]. These results suggest that β-keto-ester attaches to an electron-withdrawing group (positive value of σ p ), facilitating the condensation step with benzofurazan oxide (12) and resulting in the formation of quinoxaline 1,4-dioxide in superior yields. In contrast, no significative differences were observed for the condensation when using KF/Al 2 O 3 as the catalyst, in the absence of organic solvent.…”

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confidence: 95%

“…Benzofurazan oxide (12) reacts with enamines that are generated in situ and also with enolates in order to form quinoxaline di-N-oxide in good yield [12][13]. This reaction, which has been given the name of Beirut reaction, is an excellent method for preparing a variety of heterocyclic compounds.…”

mentioning

confidence: 99%

“…The synthetic strategy was initiated by a systematic study carried out on the condensation of benzofurazan oxide (12) with ethyl benzoylacetate in order to identify a new methodology for the synthesis of 2-(carboethoxy)-3-phenylquinoxaline 1,4-dioxide (4), previously described by Kluge and coworkers [14], followed by subsequent use of the selected methodology in the preparation of the target esters (5-11). Thus, 12 was condensed with ethyl benzoylacetate in triethylamine and chloroform (as base and solvent, respectively) at room temperature [11].…”

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confidence: 99%

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Comparative use of solvent-free KF-A1₂O₃and K₂CO₃in acetone in the synthesis of quinoxaline 1,4-dioxide derivatives designed as antimalarial drug candidates

Lima

Zarranz

Marín

et al. 2005

Journal of Heterocyclic Chemistry

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In this paper we describe two new basic conditions for the synthesis of quinoxaline 1,4‐dioxide derivatives in moderate to good yields. These conditions, exemplified by the use of K2C03 in acetone or KF/A1203 in the absence of an organic solvent, were reproducible and applicable to the synthesis of 2‐(carboethoxy)‐3‐phenylquinoxaline 1,4‐dioxide derivatives substituted in position 4 with electron‐donating or electron‐withdrawing groups.

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Beirut Reaction

2010

Comprehensive Organic Name Reactions and Reagents

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The preparation of quinoxaline‐1,4‐dioxides from the cycloaddition between benzofuroxan (i.e., benzofurazan N ‐oxide) and dienes, α,β‐unsaturated ketones, enamines, or enolates is known as Beirut reaction. Ketones, β‐diketones, β‐ketoesters, β‐ketonitrile, 1,3‐dinitrile, and β‐ketoamides have been found to be suitable for this reaction, and the corresponding enolates can be easily prepared in the presence of a weak base such as triethylamine. Phenolic enolates from phenol, resorcinol, hydroquinone, or benzoquinone undergo a similar dehydrative condensation with benzofuroxan under mild conditions to give phenazine N, N ′‐dioxide derivatives. It has been reported that the Beirut reaction from unsymmetrically monosubstitutedbenzofuroxanes affords two regio‐isomers, however only one regio‐isomer is obtained. When aroylcetopnenones are applied as the enolate precursors, the ortho ‐substituents have shown some directing effect, possibly owing to the steric hindrance.

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Enamines with isobenzofuroxan: a novel synthesis of quinoxaline-di-n-oxides

Cited by 59 publications

References 0 publications

Quinoxaline 1,4-Dioxide: A Versatile Scaffold Endowed With Manifold Activities

Quinoxaline 1,4-Dioxide: A Versatile Scaffold Endowed With Manifold Activities

Comparative use of solvent-free KF-A1₂O₃and K₂CO₃in acetone in the synthesis of quinoxaline 1,4-dioxide derivatives designed as antimalarial drug candidates

Beirut Reaction

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Enamines with isobenzofuroxan: a novel synthesis of quinoxaline-di-n-oxides

Cited by 59 publications

References 0 publications

Quinoxaline 1,4-Dioxide: A Versatile Scaffold Endowed With Manifold Activities

Quinoxaline 1,4-Dioxide: A Versatile Scaffold Endowed With Manifold Activities

Comparative use of solvent-free KF-A12O3and K2CO3in acetone in the synthesis of quinoxaline 1,4-dioxide derivatives designed as antimalarial drug candidates

Beirut Reaction

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Comparative use of solvent-free KF-A1₂O₃and K₂CO₃in acetone in the synthesis of quinoxaline 1,4-dioxide derivatives designed as antimalarial drug candidates