bis(5-oxo-DL-prolinato-N1,O2)zinc

Synthesis

1) L-glutamic acid was heated and dehydrated and cyclized to produce L-pyrrolidone carboxylic acid;

2) L-pyrrolidone carboxylic acid was reacted with zinc carbonate or alkaline zinc carbonate at 0-100C using water as medium;

3) the reaction product obtained in step 2) is cooled and crystallized, and the crystals are extracted, washed and dried to obtain zinc L-pyrrolidone carboxylic acid.