Step 1: Synthesis of ethyl 3-(4-fluorophenylamino)-3-oxopropionate.
Organic solution of diethyl malonate was added to organic solution of 4-fluorophenylamine and heated to reflux until the reaction was complete. The reaction solution was cooled to room temperature, n-hexane was added to the reaction solution, filtered, the filter residue was washed with water, and the residue was recrystallized to give ethyl 3-(4-fluorophenylamino)-3-oxopropanoate.
Step 2: Synthesis of 3-(4-fluorophenylamino)-3-oxopropanoic acid.
An aqueous solution of base was added to an organic solution of ethyl 3-(4-fluorophenylamino)-3-oxopropanoate and stirred until the reaction was complete. The organic solvent in the reaction solution was spun dry and extracted, then the pH of the aqueous phase was adjusted to 7 with hydrochloric acid solution, extracted, and the organic layers were combined and dried and spun dry to produce 3-(4-fluorophenylamino)-3-oxopropanoic acid.