(S)-ethyl 2-((3S,5aS,8aS,9aS)-3-methyl-1,4-dioxooctahydro-1H-cyclopenta[4,5]pyrrolo[1,2-a]pyrazin-2(5aH)-yl)-4-phenylbutanoate
(S)-ethyl 2-((3S,5aS,8aS,9aS)-3-methyl-1,4-dioxooctahydro-1H-cyclopenta[4,5]pyrrolo[1,2-a]pyrazin-2(5aH)-yl)-4-phenylbutanoate