Treatment of N,N'-di(quinoxalin-2-yl)diazene N-oxide 3 with strong acids did not give the expected Wallach-type hydroxylated product, but the first representative of the pentacyclic imidazo[1,2-a:4,5-b']diquinoxaline system 5. Heating in a weaker acid or neat furnished 1-(quinoxalin-2-yl)quinoxalin-2(1H)- one 12. The structures of these products were confirmed by independent synthesis and NMR experiments or X-ray crystallography.
ASJC Scopus subject areas
- Organic Chemistry