(ethoxycarbonylmethylene)-3 oxo-2 tetrahydro-1,2,3,4 quinoxaline

3-(N'-ethoxymethylene)hydrazinocarbonylmethylene-2-oxo-1,2,3,4-tetrahydroquinoxaline

3-hydrazino-carbonylmethylene-2-oxo-1,2,3,4-tetrahydroquinoxaline

(Z)-methyl 2-(3-oxo-3,4-dihydroquinoxalin-2(1H)-ylidene)acetate

3-(3H-1,3,4-oxadiazol-2-ylidenemethyl)-1H-quinoxalin-2-one