2-Naphthalenesulfonic acid, 7-(5-chloro-2,6-difluoro-4-pyrimidinyl)amino-4-hydroxy-3-(4-methoxy-2-sulfophenyl)azo-, sodium salt

7-[(5-chloro-2,6-difluoro-4-pyrimidinyl)amino]-4-hydroxy-3-[(4-methoxy-2-sulphophenyl)azo]naphthalene-2-sulphonic acid, sodium salt