InChI=1/C14H14N2O4/c1-3-20-14(19)16-15-8(2)11-12(17)9-6-4-5-7-10(9)13(11)18/h4-7,15H,3H2,1-2H3,(H,16,19 ethyl 2-[1-(1,3-dioxo-1,3-dihydro-2H-inden-2-ylidene)ethyl]hydrazinecarboxylate hydrazinecarboxylic acid, 2-[1-(1,3-dihydro-1,3-dioxo-2H-inden-2-ylidene)ethyl]-, ethyl ester