Abstract: Derivatives of O-demethylseldomycin factor 5 represented by the following formula are provided: ##STR1## wherein: R is hydrogen or loweralkyl; R.sub.1 and R.sub.2 can be either hydrogen or hydroxy with the limitation that both R.sub.1 and R.sub.2 cannot be hydroxy; R.sub.3 is selected from the group consisting of hydrogen, loweralkyl, aminoloweralkyl, diaminoloweralkyl, hydroxyloweralkyl, N-loweralkylaminoloweralkyl, aminohydroxyloweralkyl, N-loweralkylaminohydroxyloweralkyl, or ##STR2## with the limitation that when R.sub.1 is hydroxy, R.sub.3 cannot be hydrogen when R is hydrogen; and R.sub.4 is selected from the group consisting of loweralkyl, aminoloweralkyl, diaminoloweralkyl, hydroxyloweralkyl, N-loweralkylaminoloweralkyl, aminohydroxyloweralkyl and N-loweralkylaminohydroxyloweralkyl; and the pharmaceutically acceptable salts thereof. The compounds are potent anti-bacterial agents.

Abstract: 4"-O-alkylgentamicins and sagamicins represented by the formula: ##STR1## wherein R.sub.1 is hydrogen or methyl: R.sub.2 is hydrogen or methyl; R.sub.3 is hydrogen or hydroxy; R.sub.4 is hydroxy when R.sub.3 is hydrogen and hydrogen when R.sub.3 is hydroxy; and R.sub.5 is loweralkyl; and the pharmaceutically acceptable salts thereof, intermediates therefor, and compositions and methods employing the potent antibiotics of this invention.

Abstract: A new seldomycin factor 5 derivative is provided, O-demethylseldomycin factor 5. The compound is represented by the formula: ##STR1## The compound is a potent anti-bacterial agent.