Pentanoic acid, 2-oxo-, ethyl ester, Ethyl 2-oxovalerate, ethyl 2-oxopentoate, ethyl oxopentanoate, 2-oxo-valeric acid ethyl ester, Ethyl 2-oxo-pentanoate, Pentanoic acid,2-oxo-,ethyl ester, 2-Oxopentanoic acid ethyl ester, 2-Oxo-valeriansaeure-aethylester