Caprazol-3"-ester derivatives of the formula (VII) wherein Me is methyl group, R4 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 R5 is hydrogen atom or an alkyl group of 1-21 carbon atoms, or a pharmaceutically acceptable acid addition salt thereof.The novel caprazol derivatives now synthesized exhibit excellent antibacterial activities against a variety of bacteria including acid-fast bacteria.
