Siderophores of highly phytopathogenic Alternaria longipes. Structures of hydroxycoprogens

Alternaria longipes ATCC 26293, a highly phytopathogenic fungus, has been found to produce a large number of siderophores under iron-deficient conditions. Most of the compounds are members of the coprogen family. Structures of three novel siderophores, termed hydroxycoprogens, have been determined by 1H and 13C NMR, FAB mass spectrometry and partial hydrolysis. The compounds are analogs of coprogen, neocoprogen I and isoneocoprogen I, in which one of the terminal trans-anhydromevalonic acid residues is replaced by a trans-4,5 dihydroxy-3-methyl-2-pentenoic acid residue.