"' 2, 5-Diketopiperazine "', also known as "'piperazine-2, 5-dione "'and as the cyclodipeptide "'cyclo ( Gly-Gly ) "', is an organic compound and the smallest cyclic dipeptide that consists of a six-membered ring containing two amide linkages where the two nitrogen atoms and the two carbonyls are at opposite positions in the ring.
