Reaction of 5-aminoquinoxaline with alkoxymethylene derivatives affords the
corresponding quinoxalinoaminoethylenes. These undergo a thermal cyclizati
on to yield angularly annelated 10H-pyrido[2,3-f]quinoxalines. The structur
es of all products were deduced from their IR, UV, mass, H-1, and C-13 NMR
spectra.