Diethyl oxalpropionate (HYL 2-METHYL-3-OXOSUCCINATE), also known as methyloxalacetic acid diethyl ester or diethyl methyloxalacetate, is a member of the class of compounds known as beta-keto acids and derivatives. These compounds are organic compounds containing an aldehyde substituted with a keto group on the C3 carbon atom. Diethyl oxalpropionate is slightly soluble (in water) and a very weakly acidic compound (based on its pKa). Within the cell, diethyl oxalpropionate is primarily located in the cytoplasm.