PRODUCTION OF 2-PIPERAZINECARBOXYLIC ACID OR ITS SALT

摘要

PROBLEM TO BE SOLVED: To produce the subject compound in high yield by bringing cyanopiperazine into contact with an acidic aqueous solution. SOLUTION: (A) 2-Cyanopiperazine is brought into contact with (B) an acidic aqueous solution preferably having <=-1.2 acidity function (e.g. an aqueous solution of inorganic acids such as hydrochloric acid and sulfuric acid) preferably at >=40 deg.C for 1-10 hr, and the obtained reaction liquid is cooled. The resultant precipitated solid is filtrated preferably at room temperature or less to provide the objective compound. The acid in the component B in an amount of 1-50 molar times as much as the mol of the component A is preferably used in the reaction. The addition of water or a poor solvent (e.g. methanol and ethanol) preferably in an amount of 0.2-5 times in volume as much as the volume of the reaction liquid to the reaction liquid can improve the yield by reducing the loss by dissolving.