(9ci)-3-(1-甲基乙基)-1-环戊烯-1-羧酸

ethyl 1-hydroxy-2-oxocyclopentane-1-carboxylate

1-hydroxymethyl-2-oxocyclopentanecarboxylic acid ethyl ester

6-ethoxy-5,6-dioxohexanoic acid

propan-2-yl 2-oxocyclopentane-1-carboxylate