36199-70-9 N-Acetyldehydro-phe-pro diketopiperazine N-Acetyldehydrophenylalanyl-L-proline diketopiperazine N-Acetyldehydrophenylalanylproline diketopiperazine Pyrrolo(1,2-a)pyrazine-1,4-dione, 2-acetylhexahydro-3-(phenylmethylene)-