2,3-bis(acetyloxymethyl)but-3-enyl acetate

1,1,2-乙三酸

tetraethyl hexane-2,2,3,3-tetracarboxylate

ethane-1,1,2,2-tetracarboxylic acid

diethyl 4-methylidene-5-oxooxolane-3,3-dicarboxylate