N'-(4-nitrophenyl)-N-phenyloxamide

N-(4-methyl-2-nitro-phenyl)-N'-phenyl-oxalamide

N-phenyl-N'-(2,2,2-trichloro-1-hydroxy-ethyl)-oxalamide

5-imino-1,3-diphenylimidazolidine-2,4-dione

diethyl 2,2-dimethyl-3-oxobutanedioate