Glycosiderophores: synthesis of tris-hydroxamate siderophores based on a galactose or glycero central scaffold, Fe(III) complexation studies.

A series of five new hexadentate tris-hydroxamate ligands based on a d-galactose or a glycerol scaffold have been synthesized. Protonation and ferric complex formation constants have been determined from solution studies by potentiometric and spectrophotometric titrations. All ligands form 1:1 Fe:L complexes. The calculated pFe values at pH 7.4 span over the range 19.2-23.0 depending on the scaffold and on the length of the spacers between hydroxamate and central scaffold and on the N-methyl substitution. This new kind of artificial siderophores based on a glycoscaffold is of interest as it opens up an easy way to modulate the pFe.