Synonyms: S,S,S-Diketopiperazine, (2S)-2-[(3S,8aS)-3-(4-Aminobutyl)-1,4-dioxohexahydropyrrolo[1,2-a]pyrazin-2(H)-yl]-4-phenylbutanoic acid,(2S)-2-[(3S,8aS)-3-(4-Aminobutyl)-1,4-dioxohexahydropyrrolo[1,2-a]pyrazin-2(1H)-yl]-4-phenylbutanoic Acid, (αS,3S,8aS)-3-(4-Aminobutyl)hexahydro-1,4-dioxo-α-(2-phenylethyl)pyrrolo[1,2-a]pyrazine-2(1H)-acetic acid