An investigation on the effect of substituent at the 2-position of mono-substituted quinoxalines in the synthesis of di-substituted quinoxaline derivatives via nucleophilic substitution reactions, is reported. Di-substituted quinoxalines bearing aryl-alky, aryl-aryl, aryl-heteroaryl, aryl-alkynyl, and amino-alkyl substituents were prepared in moderate to good yields. 2-Monosubstituted quinoxali...

A transition metal-free process for the regioselective synthesis of pyrrolo[1,2-a]quinoxalines under mild conditions in one-pot is described. The reaction afforded a variety of products in good to excellent yields. Indolo[1,2-a]quinoxalines were also synthesized from indole-2-carboxamides under the same conditions.

3-(l-Halo-2-oxo-2-substitutedethyl)-2(lH)quinoxalinones, Furo[2,3-b]quinoxalines An efficient method for the synthesis of furo[2,3-b]quinoxalines has been devised. Thus, 3-halo-2-arylfuro[2,3-b]quinoxalines, 5a-5c were synthesized by the action of conc. H2SO4 on 3-(l-halo-2-oxo-2-arylethyl)-2(lH)quinoxalinones, 3b, 3c and 3f respectively. When 3-(1 -halo-2-oxo-2-substitutedethyl)-2(1H)quinoxali...

of Restenosis To the Editor: We would like to point out several issues related to citations of the scientific literature in an article by Yamasaki et al.1 We would like to emphasize that quinoxalines were the first compounds showing excellent efficacy in inhibiting balloon injury–induced stenosis in pigs and rats. Reference 20 in the article by Yamasaki et al, which describes this study, is not...

Oxazolo[5,4-f]quinoxalines, thiazolo[5,4-f]quinoxalines and pyrazino[b,e]isatins were all obtained from 5-iodo-6-aminoquinoxalines. While the first two families synthesized by nitrogen functionalization subsequent copper-catalyzed cyclization, latter was Sonogashira coupling, alkyne hydration, oxidative cyclization. Most of polycycles evaluated in biological tests.

In continuation of our study the in vitro antioxidant activity of some novel quinoxaline derivatives was investigated by 1,1-diphenyl-2-picrylhydrazyl (DPPH) method with respect to ascorbic acid. To determine the antioxidant activity, a number of substituted indoxyls (3A-G), cyclic ketones (2A-G), and quinoxalines (1A-G) were synthesized by both microwave and conventional heating methods. The p...

ABSTRACT Copper-free, Pd/C-catalyzed, one-pot reaction of 2,3-dichloroquinoxaline with hydrazine hydrate, bromine, phenylacetylene, and a variety of aldehydes provides an efficient and direct method for the preparation of 1-aryl-4-(2-phenylethynyl)[1,2,4]triazolo[4,3-a]quinoxalines in water at 70 °C. This methodology involves the use of inexpensive reagents or catalysts, and thus permits a new ...

A microwave-induced iodine-catalyzed simple, rapid and convenient synthesis of different types of quinoxalines via condensation of 1,2-diamines with 1,2-dicarbonyl compounds has been accomplished with an excellent yield.

Hypervalent iodine(III)-induced oxidative [4+2] annulation of o-phenylenediamines and electron-deficient alkynes under metal-free conditions has been developed. The reaction allows for direct access to quinoxalines bearing two electron-withdrawing groups in an efficient manner.

A gold-catalyzed oxidation of arylallenes to form α-diketones and aldehydes in good yields is presented. Further directed synthesis of quinoxalines and benzimidazoles, via the condensation of the resulting α-diketones and aldehydes with benzene-1,2-diamine, was achieved in high yields.