The structures of fortimicins C, D, and KE.

Abstract
Fortimicins C, D, and KE are new aminocyclitol antibiotics produced by a mutant of fortimicin-producing organisms [Micromonospora sp.]. Their structures have been determined by 1H and 13C NMR and mass spectra and chemical degradations. Fortimicin C is 4-N-hyantoylfortimicin B, fortimicin KE is 6''-demethylforitimicin B and fortimicin D is 4-N-glycylfortimicin KE. The last 2 antibiotics have purpurosamine C instead of 6-epi-purpurosamine B.