Pyrrolo-indole derivatives

A DC-89 derivative represented by the formula ##STR50## wherein X represents Cl or Br;

• R represents substituted or unsubstituted lower alkyl (wherein the substituted lower alkyl is substituted with 1 to 3 moieties selected from the group consisting of lower alkoxy, lower alkylthio optionally substituted with carboxy, carboxy, lower alkoxycarbonyl, benzyloxycarbonyl, amino, mono- or di(lower alkyl)amino, cyclic amino optionally substituted with lower alkyl or cyclic amino, halogen and phenyl), substituted or unsubstituted C.sub.7-20 aralkyl, COR.sup.1 (in which R.sup.1 represents hydrogen, substituted or unsubstituted C.sub.6-10 nonheterocyclic aryl, substituted or unsubstituted heterocyclic group selected from the group consisting essentially of pyridyl, pyrazinyl and pyrimidinyl (wherein the substituted aralkyl, the substituted aryl and substituted heterocyclic group are substituted with 1 to 3 moieties independently selected from the group consisting of substituted or unsubstituted lower alkyl, lower alkoxy, lower alkoxycarbonyl, amino, mono- or di(lower alkyl)amino, pyrrole and halogen), OR.sup.2 (in which R.sup.2 represents substituted or unsubstituted lower alkyl or aryl), SR.sup.2, NR.sup.3 R.sup.4 (in which R.sup.3 and R.sup.4 independently represent hydrogen, amino, or mono- or di(lower alkyl)amino, provided that R.sup.3 and R.sup.4 are not hydrogen at the same time), ##STR51## in which R.sup.5 represents NR.sup.7 (in which R.sup.7 represents hydrogen or substituted or unsubstituted lower alkyl) or oxygen, and R.sup.6 is the same meaning as R.sup.7 defined above or ##STR52## or SO.sub.2 R.sup.8 (in which R.sup.8 represents substituted or unsubstituted lower alkyl or substituted or unsubstituted aryl);
• and Y represents ##STR53## or pharmaceutically acceptable salts thereof.