Caprazene-1"-ester derivatives of the formula (III)wherein Me is methyl group, R2 is a straight chain or a substantially straight chain alkyl group of 5-21 carbon atoms or a straight chain or a substantially straight chain alkenyl group of 5-21 carbon atoms or an alkynyl group of 5-21 carbon atoms and A is hydrogen atom or an amino-protecting group which is an alkoxycarbonyl group or an aralkyloxycarbonyl group, or a pharmaceutically acceptable acid addition salt thereof.The novel caprazene derivatives exhibit excellent antibacterial activities against a variety of bacteria including acid-fast bacteria.
