.alpha.-(Carboethoxy)cyclopentanone 2-(Ethoxycarbonyl)cyclopentanone 2-Carbethoxy-1-cyclopentanone 2-Carbethoxycyclopentanone 2-Cyclopentanonecarboxylic acid ethyl ester 611-10-9 Cyclopentanecarboxylic acid, 2-oxo-, ethyl ester Ethyl 2-cyclopentanone-1-carboxylate Ethyl 2-cyclopentanonecarboxylate Ethyl 2-oxo-1-cyclopentanecarboxylate Ethyl 2-oxocyclopentanecarboxylate Ethyl 2-oxoocyclopentanecarboxylate Ethyl cyclopentanone-2-carboxylate NSC5658