Compounds of the general formula as free acid, salt or mixed salt wherein R 1 signifies H, a sulpho group or halogen, R 2 signifies H or a sulpho group, R 3 signifies H, a sulpho group or halogen R 4 signifies H, a sulpho group or halogen, R 5 signifies H, a substituted C 1 to C 4 alkyl group or an unsubstituted C 1 to C 4 alkyl group or halogen, wherein the substituents of the substituted C 1 to C 4 alkyl group are selected from -OH, -O(C 1 to C 4 - alkyl), -SO 3 H and-COOH, R 6 signifies an C 1 to C 4 alkyl group, a carboxy group or a carbo C 1 to C 4 alkoxy group, R 7 signify H, a sulpho group, a substituted C 1 to C 4 alkyl group or an unsubstituted C 1 to C 4 alkyl group, a substituted C 1 to C 4 alkoxy group or an unsubstituted C 1 to C 4 alkoxy group, wherein the substituents of the substituted C 1 to C 4 alkyl group are selected from -OH, -O(C 1 to C 4 -alkyl), -SO 3 H and -COOH, and wherein the substituents of the substituted C 1 to C 4 alkoxy group are selected from -OH, -O(C 1 to C 4 - alkyl), -SO 3 H and -COOH, R 8 signifies H, a substituted C 1 to C 4 alkyl group or an unsubstituted C 1 to C 4 alkyl group, a substituted C 1 to C 4 alkoxy group or an unsubstituted C 1 to C 4 alkoxy group, wherein the substituents of the substituted C 1 to C 4 alkyl group are selected from -OH, -O(C 1 to C 4 - alkyl), -SO 3 H and -COOH, and wherein the substituents of the substituted C 1 to C 4 alkoxy group are selected from -OH, -O(C 1 to C 4 - alkyl), -SO 3 H and -COOH, B signifies a group with the formula -SO 2 -, -NH-CO-NH-, -CR 9 R 10 -, wherein R 9 signifies H, or a unsubstituted C 1 to C 9 alkyl group or a substituted C 1 to C 9 alkyl group wherein the substituents of the substituted C 1 to C 9 alkyl groups are selected from the following substituents -OH, -O(C 1 to C 4 - alkyl),-SO 3 H, -COOH, R 10 signifies a unsubstituted C 1 to C 9 alkyl group or a substituted C 1 to C 9 alkyl group wherein the substituents of the substituted C 1 to C 9 alkyl groups are selected from the following substituents -OH, -O(C 1 to C 4 - alkyl), -SO 3 H,-COOH, or a substituted aryl group or R 10 signifies a unsubstituted aryl group provided that R 7 does not signify H, characterized in that the compounds of formula bear at least one anionic substituent. R 1 signifies H, a sulpho group or halogen, R 2 signifies H or a sulpho group, R 3 signifies H, a sulpho group or halogen R 4 signifies H, a sulpho group or halogen, R 5 signifies H, a substituted C 1 to C 4 alkyl group or an unsubstituted C 1 to C 4 alkyl group or halogen, wherein the substituents of the substituted C 1 to C 4 alkyl group are selected from -OH, -O(C 1 to C 4 - alkyl), -SO 3 H and-COOH, R 6 signifies an C 1 to C 4 alkyl group, a carboxy group or a carbo C 1 to C 4 alkoxy group, R 7 signify H, a sulpho group, a substituted C 1 to C 4 alkyl group or an unsubstituted C 1 to C 4 alkyl group, a substituted C 1 to C 4 alkoxy group or an unsubstituted C 1 to C 4 alkoxy group, wherein the substituents of the substituted C 1 to C 4 alkyl group are selected from -OH, -O(C 1 to C 4 -alkyl), -SO 3 H and -COOH, and wherein the substituents of the substituted C 1 to C 4 alkoxy group are selected from -OH, -O(C 1 to C 4 - alkyl), -SO 3 H and -COOH, R 8 signifies H, a substituted C 1 to C 4 alkyl group or an unsubstituted C 1 to C 4 alkyl group, a substituted C 1 to C 4 alkoxy group or an unsubstituted C 1 to C 4 alkoxy group, wherein the substituents of the substituted C 1 to C 4 alkyl group are selected from -OH, -O(C 1 to C 4 - alkyl), -SO 3 H and -COOH, and wherein the substituents of the substituted C 1 to C 4 alkoxy group are selected from -OH, -O(C 1 to C 4 - alkyl), -SO 3 H and -COOH, B signifies a group with the formula -SO 2 -, -NH-CO-NH-, -CR 9 R 10 -, wherein R 9 signifies H, or a unsubstituted C 1 to C 9 alkyl group or a substituted C 1 to C 9 alkyl group wherein the substituents of the substituted C 1 to C 9 alkyl groups are selected from the following substituents -OH, -O(C 1 to C 4 - alkyl),-SO 3 H, -COOH, R 10 signifies a unsubstituted C 1 to C 9 alkyl group or a substituted C 1 to C 9 alkyl group wherein the substituents of the substituted C 1 to C 9 alkyl groups are selected from the following substituents -OH, -O(C 1 to C 4 - alkyl), -SO 3 H,-COOH, or a substituted aryl group or R 10 signifies a unsubstituted aryl group provided that R 7 does not signify H,