The reaction of 3-ethoxycarbonylmethylene-2-oxo-1, 2, 3, 4-tetrahydroquinoxaline with the Vilsmeier reagent gave 3-(N, N-dimethylaminocarbonyl) furo [2, 3-b] quinoxaline, which was converted to various quinoxaline derivatives, 3-methyl-2-oxo-1, 2-dihydroquinoxaline, quinoxalinylpyrazolin-5-ones, and pyrazolo [3', 4' : 3, 4] pyridazino [5, 6-b] quinoxalines.
