To obtain the subject compound that is useful as a synthetic intermediate for a herbicidal compound by reaction of dichlorosuccinate with amine followed by reaction of the product with an aqueous acid.

A dichlorosuccinate of formula I (R is a 1-4C alkyl) and an amine of the formula: R1R2NH (R1 and R2 are each H, a 1-6C alkyl, they corporate together with N to form a 5 or 6-membered ring) are allowed to react with each other in an inert solvent at 25°C up to the refluxing whereby forming a mixture of an alkylamino matleate or alkylamino fumarate of formula II and chloroamino succinate of formula III. Further, the mixture of formula II and the formula III is hydrolyzed with an aqueous acid to give dialkyl oxalacetate of formula IV. The compound of formula I is useful as a synthetic intermediate for quinoline-2,3-dicarboxylic acid, a precursor of a herbicide.