2,2,6,6-tetramethyl-4-oxo-heptanedioic acid

5,5-二甲基丙二酰脲

1-O-ethyl 3-O-(2-nitrophenyl) 2,2-dimethylpropanedioate

1-O-(2,4-dinitrophenyl) 3-O-ethyl 2,2-dimethylpropanedioate

二甲基丙二酰二氯