6-(4-Nitrobenzamido)-1-naphthol-3-sulfonic acid

1-Hydroxy-6-(4-nitrobenzoylamino)-3-naphthalenesulfonic acid

4-hydroxy-7-[(4-nitrobenzoyl)amino]naphthalene-2-sulfonic acid

4-Hydroxy-7-[(4-nitrobenzoyl)amino]-2-naphthalenesulfonic acid

4-hydroxy-7-[(4-nitrobenzoyl)amino]naphthalene-2-sulphonic acid

4-hydroxy-7-[(4-nitrophenyl)carbonylamino]naphthalene-2-sulfonic acid