Abstract: New derivatives of the antibiotic butirosin A having the formula: ##STR1## in which R is a radical of formula (II): ##STR2## and pharmaceutically acceptable acid addition salts thereof. The butirosin A derivatives of formula (I) can be prepared by reduction of a 5"-azido compound having the formula (III): ##STR3## in which R' is the same groups R or a group which, on reduction, gives a group of formula (II).The butirosin A derivatives of general formula (I) and pharmaceutically acceptable acid addition salts thereof are active against a broad spectrum of Gram-positive and Gram-negative bacteria, including some butirosin-resistant strains.

Abstract: New derivative of butirosin A, 3', 4'-dideoxybutirosin A having not only broad antibacterial activities against gram-positive and -negative bacteria but also an activity against butirosin-resistant bacteria with a low toxicity. It is prepared from the corresponding 3', 4'-dideoxy-3'-eno derivative derived from butirosin A or a mixture of butirosins A and B by catalytic reduction.