Total Synthesis of Ferrichrome

Abstract

Abstract Two different sequence hexapeptides for the synthesis of ferrichrome were prepared using Nδ-tosyl-Nδ-benzyloxy-l-ornithine by means of N-hydroxysuccinimide plus N,N-dicyclohexylcarbodiimide or Woodward reagent K method. The linear hexapeptides (XII·HCl and XIX·HCl) were cyclized by excess N,N-dicyclohexylcarbodiimide to give cyclo-triglycyltri-Nδ-tosyl-Nδ-benzyloxy-l-ornithyl (XX). Detosylation, acetylation and successive reductive debenzylation of XX afforded deferri-ferrichrome (XXIV). Addition of ferric iron to XXIV gave ferrichrome, which had the same crystalline form, superimposable infrared and well-agreeing visible spectra and the same value in optical rotation compared with the data in the literature of natural product.