From 2-Fluoro-l-nitrobenzenes

When indole-2-carboxamides were used instead pyrrole-2-carboxamides it was possible, by analogy, to synthesize indolo[l,2-a]quinoxalines in 82-92 % yields (Huang et al. 2011). 

The strategy of building the pyrazine ring of the quinoxaline system is fundamentally different in the case of 4-bromo-5-nitrophthalonitrile 409, with two nitrile groups which activate the other substituents on the benzene ring toward the nucleophilic aromatic substitution. 

7 From N-Aryl-2-nilrosoanilines and Alkylated Cyanoacetic Esters 

Reactions of 2-nitrosoarylamines with carbon nucleophiles leading to quinoxalin-2(17f)-one A-oxides are mentioned in literature, but the reported examples are limited to a few intramolecular reactions of pyrimidine derivatives, easy to synthesize via the direct nitrosation of appropriate aminopyrimidines (Pachter et al. 1963 Steinlin et al. 2008 Steinlin and VaseUa 2009). Because carbocyclic o-nitrosoaniUnes were not so easily available, the common synthesis of 

a new simple, convenient, and general method of the synthesis of various quinoxalin-2-one A-oxides was presented. The synthesis started from easily accessible substrates, that is, alkyl cyanoacetic esters and 2-nitroso-N-aiylaniIines which can be prepared from appropriate nitroarenes and anilines. Diversity of the compounds can be achieved by simply varying the substituents in each reagent. 

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