A group of molecules with the name diketopiperazines (DKP) are called so, because of their diketopiperazine ring as the core structural unit. Mainly there are 3 types of diketopiperazies which only differ in in the position of the keto group, one type has the keto groups in 2,3- position; another in 2,5-; and the third in 2,6- position. The 2,5- isomer has attracted great interest, because of compounds ...