<p>A DC-89 derivative represented by general formula (I) or a pharmacologically acceptable salt thereof, wherein X represents Cl or Br; R represents (un)substituted alkyl, (un)substituted aralkyl, COR<1> or SO2R<7>; and Y represents the group (a) or (b). The compound has an excellent antitumor activity and is useful as an antitumor drug. <CHEM></p>
