1,3'-Bipyridinium, 5'-((2,5-dichlorophenyl)azo)-1',2'-dihydro-6'-hydroxy-4'-methyl-2'-oxo-, salt with hydroxybutanedioic acid (1:1) 5'-((2,5-Dichlorophenyl)azo)-1',2'-dihydro-6'-hydroxy-4'-methyl-2'-oxo-1,3'-bipyridinium malate 68214-61-9 EINECS 269-303-5