One-pot green synthesis of pidotimod in water

Pidotimod is an immunostimulant drug that plays an important role in respiratory diseases. There are several methods for the preparation of pidotimod but require complicated procedures. Herein, we report the one-pot, direct synthesis of the immunostimulant drug pidotimod via the reaction of thiazolidine-4-carboxylic acid and L-pyroglutamic acid in water without the protection step. The reaction runs well at room temperature and simple purification process. We believe that this result could bring a new green method for application in the pharmaceutical industry. Graphical abstract