Abstract
Racemomycin-A, one of streptothricin-group antibiotics, was condensed with aromatic aldehydes. These N-phenylalkylidene derivatives were active against gram-positive and-negative bacteria and Mycobacterium, and showed a tendency of lower delayed toxicity in mice. N-Phenylalkyl and N-acetyl derivatives of Racemomycin-A showed poor antimicrobial activity but with weaken delayed toxicity.