Chemical modification of fortimicin A

Chlorination of antibiotic fortimicin A with triphenylphosphine and carbon tetrachloride has been attempted, and 2-chloro-, 2,5-dichloro-, and 2-chloro-4-ene derivatives have been obtained. Successive dehalogenation of the chlorinated fortimicins A with tributylstannane gave the corresponding deoxyfortimicins A. Among five deoxyfortimicins A, 2-deoxyfortimicin A exhibits improved antimicrobial activity, compared to the parent fortimicin A.