Method of preparing alkaline earth metal salts of 2-pyrrolidone-5-carboxylic acid

摘要

Alkaline earth metal salts of 2-pyrrolidone-5-carboxylic acid (pyroglutamic acid) are prepared by heating the corresponding alkaline earth metal salt of glutaminic acid in the solid state to a temperature in a range of 120 DEG C. to 250 DEG C. until the water liberated by the intramolecular condensation (cyclocondensation) has been completely eliminated.