167. Syntheses of 2-monosubstituted and 2 : 3-disubstituted quinoxalines

Gowenlock, A. H.; Newbold, G. T.; Spring, F. S.

doi:10.1039/jr9450000622

Cited by 52 publications

(12 citation statements)

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“…[20][21][22] Also, the coupling constants of the styryl protons, in 1 H-NMR spectra, are 15-16 Hz, confirming its trans configuration . 10,21,22 On the other hand, 3-ethoxycarbonyl-2(1H)-one (6) was prepared 23 and treated with hydrazine hydrate to afford 3-hydrazinocarbonyl quinoxalin-2(1H)-one (7). 24 The latter was used as a versatile compound for the building of other new heterocyclic systems.…”

Section: Resultsmentioning

confidence: 99%

Synthesis and Antimicrobial Activity of Novel Quinoxaline Derivatives

Badran

Moneer

Refaat

et al. 2007

J Chinese Chemical Soc

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In this study, certain 3‐substituted styrylquinoxalin‐2(1H)‐ones (2a‐d) and their 2‐chloro (3a‐d) and 2‐piperazinyl derivatives (4a‐g) were synthesized from 3‐methylquinoxalin‐2(1H)‐one (1). In addition, a series of 1‐alkyl‐3‐substituted styrylquinoxalin‐2(1H)‐ones (5a‐d) was also prepared. Moreover, 3‐(N2‐arylidenehydrazinocarbonyl)quinoxalin‐2(1H)‐ones (8a‐c) as well as their cyclized oxadiazolinyl derivatives (9a‐c) were prepared from 3‐hydrazinocarbonylquinoxalin‐2(1H)‐one (7). Furthermore, 3‐(5‐substituted thio‐1,3,4‐oxadiazol‐2‐yl)quinoxalin‐2(1H)‐ones (11a‐c) and (12a‐c) were obtained from the intermediate compound (10) ‐ previously obtained via cyclization of (7) with CS2. Likewise, 3‐(5‐oxo‐4,5‐dihydro‐(1,3,4‐oxadiazol‐2‐yl)quinoxalin‐2(1H)‐one (13), 3‐[5‐(4‐nitrophenyl)‐1,3,4‐oxadiazol‐2‐yl]‐quinoxalin‐2(1H)‐one (14) and its 2‐chloro derivative (15) were prepared from 3‐hydrazinocarbonylquinoxalin‐2(1H)‐one (7). Some of these derivatives were evaluated for antimicrobial activity in vitro and some of the tested compounds showed antibacterial or antifungal activity.

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Section: Resultsmentioning

confidence: 99%

Synthesis and Antimicrobial Activity of Novel Quinoxaline Derivatives

Badran

Moneer

Refaat

et al. 2007

J Chinese Chemical Soc

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“…To ester 7 (9.94 g, 42 mmol), dissolved in aqueous methanol (80%, 200 mL), was added Na 2 CO 3 (2.50 g, 24 mmol) and the reaction mixture was refluxed for 4 h. Then the solution was acidified with 2 M HCl and the solvent was removed under reduced pressure to yield the crude acid 8, which was used 'as is' in the next reaction, mp 142-145 °C (lit. [23] …”

Section: -Chloro-3-methylquinoxalinementioning

confidence: 97%

Pyrazolo[4′,3′:5,6]pyrano[2,3‐b]quinoxalin‐4(1H)‐one: Synthesis and characterization of a novel tetracyclic ring system

Eller¹,

Datterl²,

Hölzer³

2007

Journal of Heterocyclic Chem

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Derivatives of the hitherto unknown ring system, pyrazolo[4′,3′:5,6]pyrano[2,3‐b]quinoxalin‐4(1H)‐one, are synthesized in one step from the corresponding 1‐substuituted or 1,3‐disubstituted 2‐pyrazolin‐5‐ones and 3‐chloroquinoxaline‐2‐carbonyl chloride using calcium hydroxide in boiling 1,4‐dioxane. The parent system carrying no substituent in positions 1 and 3 is obtained upon treatment of the 1‐PMB (p‐methoxybenzyl) protected congener with trifluoroacetic acid. Detailed NMR spectroscopic investigations including unambiguous chemical shift assignments of all 1H, 13C, and 15N resonances of the obtained tetracycles are reported.

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“…This involves nucleophilic substitution of two equivalents of 2-chloropyrazine or 2-chloroquinoxaline [12] by hydroquinone in warm N,N-dimethylformamide in the presence of potassium carbonate (Scheme 1) [13,14]. The ligands were characterised by elemental analysis, mass spectrometry and 1 H and 13 C NMR.…”

mentioning

confidence: 99%