| abstract |
A nitrogen-containing tetracyclic compound represented by the formula: <CHEM> wherein Y<1>-Y<2>-Y<3> is N-C=N or a group represented by the formula: C=C-NR<3> (wherein R<3> is a hydrogen atom, a C1-5 alkyl group or a nitrogen-containing C2-10 alkyl group), Y<4> is S, SO, SO2, CH2 or a group represented by the formula: NR<4> (wherein R<4> is a C1-5 alkanoyl group or a C1-5 alkyl group), R<1> and R<2> are the same or different, and are each a hydrogen atom, a C1-10 alkyl group, a C3-15 alkoxyalkyl group or a C3-15 alkylaminoalkyl group, or R<1> and R<2> taken together with the nitrogen atom to which they are attached form a cyclic amino group, X<1> and X<2> are the same or different, and are each a hydrogen atom, a C1-5 alkyl group, a C1-5 alkoxy group or a halogen atom, and n is 0, 1 or 2; or a pharmaceutically acceptable salt thereof. |