1-Fenyl-3-methyl-2-pyrazolin-5-on [Czech] 1-Phenyl-3-methyl-5-oxo-2-pyrazoline 1-Phenyl-3-methyl-5-pyrazolone 1-Phenyl-3-methylpyrazolone 1-Phenyl-3-methylpyrazolone-5 115566-83-1 12235-58-4