Synthesis of Erythrochelin : A Hydroxamate-Type Siderophore from Saccharopolyspora erythraea

Erythrochelin, a hydroxamate-type siderophore produced by Saccharopolyspora erythraea, is synthesized for the first time. A key building block of erythrochelin containing the 2,5-diketopiperazine ring is prepared by intramolecular cyclization of the corresponding dipeptide precursor derived from two kinds of protected δ-N-hydroxy-L-ornithines. Consecutive condensation of the building block with protected D-serine and protected δ-N-hydroxy-D-ornithine, followed by deprotection, furnishes erythrochelin