4- Acyl-quinoxaline-2-ones

The M-acylation of primary or secondary amino groups attached to quinoxaline or the ring NH group(s) of reduced quinoxalines can be done for several reasons, one of which is subsequent intramolecular cyclization (see Section 6.3.2.5). The following examples illustrate such acylations and related processes. 

The Kalinski method uses the Ugi(4CR) reaction of 2-bromoanilines, ketones/aldehydes, a carboxylic acid and an isocyanide in polar protic solvents, and the Pd-catalyzed intramolecular N-arylamidation with the formation of A -alkyl and A -acyl derivatives of quinoxalin-2-ones. 

It is reasonable to assume that the acylation of the reaction product 110 with acetic anhydride provides the formation of 3-[2-(3-acetylbenzimidazol-2-on-l-yl) vinyl]-lH-quinoxalin-2-one 111, rather than the 3-(quinoxalin-2(lH)-on-3-yl)-1-acetyl-l,2-dihydro-3H-l,5-benzodiazepin-2-one 112 as shown in the paper (Kurasawa et al. 1985b) (Scheme 6.39). 

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