Methods have been developed for preparation of 4-N-arenesulfonyifortimicins B and 4-N-alkanesulfonylfortimicins B from derivatives of fortimicin B-1, 5-carbamate. 4-N-(2-Aminoethanesulfonyl)fortimicin B and 4-N-(p-aminobenzenesulfonyl)fortimicin B have been prepared and found to be devoid of antibacterial activity.
