The structures of fortimicins C, D, and KE

Fortimicins C, D, and KE are new aminocyclitol antibiotics produced by a mutant of fortimicin-producing organisms. Their structures have been determined by 1H and 13C NMR and mass spectra and chemical degradations. Fortimicin C is 4-N-hydantoylfortimicin B, fortimicin KE is 6'-demethylfortimicin B, and fortimicin D is 4-N-glycylfortimicin KE. The last two antibiotics have purpurosamine C instead of 6-epi-purpurosamine B.