1,3-Cyclohexadien-r-5,c-6-dicarbonsaeure-diethylester

(8R*,9R*)-3,5-Dioxo-4-phenyl-2,4,6-triazatricyclo<5.2.2.02,6>undecan-8,9-dicarbonsaeure

3-(p-Chloranilino)phthalsaeureanhydrid

2-phenyl-4,5,8,9-tetrahydro-5,8-ethano[1,2,4]triazolo[1,2-a]pyridazine-1,3-dione