2-Pyrazolin-5-one, 3-methyl-4-(p-tolylazo)- 2554-35-0 3-Methyl-4-(p-tolylazo)-2-pyrazolin-5-one 3H-Pyrazol-3-one, 2,4-dihydro-5-methyl-4-((4-methylphenyl)azo)- 4-(4'Tolyl-azo)-3-methyl-pyrazolon-(5) [German] F 2342