InChI=1/C13H19NO4/c1-4-18-12(17)13(9-14,7-5-10(2)15)8-6-11(3)16/h4-8H2,1-3H ethyl 2-cyano-5-oxo-2-(3-oxobutyl)hexanoate hexanoic acid, 2-cyano-5-oxo-2-(3-oxobutyl)-, ethyl ester