Photocyclisation of 2-aroylquinoxalines; formation of coloured indolo[l,2-a]quinoxalines

Atfah, A.; Muhammad, Y; Abu-Shuheil,; Hill, John M.

doi:10.1016/s0040-4020(01)96016-8

Cited by 32 publications

(9 citation statements)

References 18 publications

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“…However, the reaction with aliphatic aldehyde 5j, afforded the desired product 6l in 65 % yield ( Table 2, entry 12). Reaction of 2-(3-methyl-1H-indol-1-yl)aniline (4c) and 4-fluoro-2-(3-methyl-1H-indol-1-yl)aniline (4d) provided the expected products 6m-q in good to excellent yields ( Table 2, entries [11][12][13][14][15].…”

Section: Resultsmentioning

confidence: 99%

“…Although a number of methods are available for the synthesis of simple substituted quinoxalines, [8,9] only a limited amount of work has been done on the synthesis of polycyclic quinoxalines, especially indoloquinoxalines. [10][11] Furthermore, to the best of our knowledge, none of the reported procedures have described the selective synthesis of dihydroquinoxalines or quinoxalines. Reported syntheses of indolo-and pyrrolofused quinoxalines involves the reaction of aryl amines with terminal alkynes in the presence of a ruthenium hydride complex for 20-24 h.…”

Section: Introductionmentioning

confidence: 99%

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Lewis Acid‐Catalyzed Selective Synthesis of Diversely Substituted Indolo‐ and Pyrrolo[1,2‐a]quinoxalines and Quinoxalinones by Modified Pictet–Spengler Reaction

et al. 2011

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An efficient tandem process for the selective synthesis of 1,2‐annulated α‐fused quinoxalines using benzotriazole methodology by a modified Pictet–Spengler reaction is described. The approach involves the reaction of arylamines 4 with aromatic aldehydes 5 to furnish 6‐endo‐dig‐cyclized products. Dihydroquinoxalines 6 were selectively obtained by using AlCl3 in tetrahydrofuran (THF) at room temperature for two hours. However, after ten hours, quinoxalines 7 were obtained exclusively in excellent yields. A series of biologically important fluoro‐ and piperazenyl‐substituted quinoxalines were also synthesized. This developed methodology also provides access to a novel tandem synthesis of quinoxalinones 9.

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Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Lewis Acid‐Catalyzed Selective Synthesis of Diversely Substituted Indolo‐ and Pyrrolo[1,2‐a]quinoxalines and Quinoxalinones by Modified Pictet–Spengler Reaction

et al. 2011

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“…The proposed mechanism of photocyclization for the transformation 20b → 21b and the role of protonation are clear from the scheme [14]. The quinoxalines 24 with β-dicarbonyl, β-dinitrile, and β-nitrilecarbonyl fragments, produced in the reaction of 3-(α-chlorobenzyl)quinoxalin-2-one (23) with the anions of β-dicarbonyl compounds, dicyanomethane, and cyanoacetic ester, form the pyrroloquinoxalines 25 when treated with acetic acid [15].…”

Section: Production Methods Of Type a (Version A1)mentioning

confidence: 99%

“…Thus, substituted derivatives of benzoylquinoxaline 20a-f undergo cyclization during UV irradiation; the cyclization is accelerated by the presence of trifluoroacetic or p-toluenesulfonic acid [14].…”

Section: Production Methods Of Type a (Version A1)mentioning

confidence: 99%

Pyrrolo[1,2-a]quinoxalines based on quinoxalines (Review)

Мамедов

Калинин

2010

Chem Heterocycl Comp

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Published data on methods for the synthesis of pyrrolo [1,2-a]quinoxalines, based on derivatives of quinoxalines and also on compounds that are not initially derivatives of quinoxalines or pyrroles are summarized and classified.Derivatives of pyrrolo[1,2-a]quinoxalines have valuable characteristics and, in particular, marked biological activity and are a subject of constant interest. In spite of this, however, data on the synthesis of these compounds remain disconnected. The only review [1], devoted to pyrroloquinoxalines and appearing in a monograph published in 1979, presents data mostly covering the period from 1965 to 1975. The review is devoted not only to the synthesis of pyrrolo[1,2-a]quinoxalines but also to the synthesis of pyrrolo[2,3-b]-, pyrrolo[3,4-b]-, and pyrrolo[1,2,3-de]quinoxalines and their physicochemical characteristics. While covering so many questions in a single review the authors simply present the existing information without analyzing the methods used for their synthesis. From the review it is difficult to form an opinion as to which of the methods is more promising and to think of any new methods for their synthesis.In the present review an attempt is made to examine all possible ways of assembling the pyrrolo-[1,2-a]quinoxaline skeleton from various fragments on the basis of an analysis of its structure. N N Pyrrolo[1,2-a]quinoxalines 1 2 3 4 5 6 7 8 9 Without touching on the integrity of the benzene ring, the creation of the pyrrolo[1,2-a]pyrazine system can be represented by one of five types of construction depending on the number of atoms entering into the composition of the initial fragments: A (9+0), B (8+1), C (7+2), D (6+3), E (6+2+1 or 6+1+2); the number of

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“…The presence of a β-dicarbonyl and α-iminocarbonyl fragments in combination with other functional groups in 3-alkanoylquinoxalin-2(1H)-one molecules makes them promising key compounds in the synthesis of condensed heterocyclic systems via annelation of different heterocycles on the a and b sides of the quinoxaline [1][2][3][4][5][6][7][8]. The availability of alkanoylquinoxalin-2(1H)-ones containing in position 3 different alkyl fragments readily transformed to other functional groups opens up novel possibilities for the use of these hetaryl ketones in the synthesis of more complex and diverse pharmacologically interesting heterocycles.…”

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confidence: 99%