2,7-Naphthalenedisulfonic acid, 4-amino-6-[[5-[[(5-chloro-2,6-difluoro-4-pyrimidinyl)amino]methyl]-1-sulf o-2-naphthalenyl]azo]-5-hydroxy-3-[[2-methoxy-5-methyl-4-[[2-(sulfooxy) ethyl]sulfonyl]phen