Patent ID: 7053082

Claim:
A compound of the Formula (I) wherein R 1 is methyl, formyl, carboxy, cyano, —CH═NOH, —CH═NNHCONH 2 or —CO—NR 5 R 6 , wherein R 5 and R 6 independently from each other are hydrogen or lower alkyl or together with the nitrogen atom to which they are attached, form a 5- or 6-membered, saturated or unsaturated heterocyclic ring optionally containing one or more further nitrogen, sulfur and/or oxygen atoms; R 2 is nitro or amino; R 3 is hydrogen, lower alkanoyl, or —CONR 7 R 8 wherein R 7 and R 9 independently from each other are hydrogen, lower alkoxy, lower alkyl, or lower cycloalkyl, or together with the nitrogen atom to which they are attached, form a 5- or 6-membered, saturated or unsaturated heterocyclic ring optionally containing one or more further nitrogen, sulfur and/or oxygen atoms; R 4 is hydrogen or lower alkyl; and the dotted lines have the following meanings: if R 3 and R 4 are not present, the bond between positions C 8 and C 9 is a single bond, and the bond between positions C 8 and N 7 is a double bond; if R 3 and R 4 are present, the bonds between positions C 8 and C 9 and between positions C 8 and N 7 are single bonds; and if R 3 is present and R 4 is missing, the bond between positions C 8 and C 9 is a double bond and the bond between positions C 8 and N 7 is a single bond; or a pharmaceutically acceptable salt thereof.