2,5-Piperazinedione, 3-[3-[N-[N-(N(sup.alpha.)-acetyl-N(sup.gamma.)-formyl- N(sup.gamma.)-hydroxy-L-ornithyl)-L-seryl]-N-(hydroxy) amino]propyl]-6-[3-(N-formyl-N-hydroxyamino)propyl]-, (3S,6S) Foroxymithine NSC612475