3-amino-3-demethoxyfortimicin A and the C-2 epimeric-2-amino-3-O-demethyl-2-deoxyfortimicins A.

Selective reactions of 3-O-demethyl-3-O-methanesulfonyl-4-N, 5-O-methylenefortimicin derivatives have been used as the key steps in the syntheses of 3-amino-3-demethoxyfortimicin A and the C-2 epimeric 2-amino-3-O-demethyl-2-deoxyfortimicins A. In vitro antibacterial activities of the new fortimicin derivatives are reported.