2-(3,4-Dimethylphenyl)-1,2-dihydro-5-methyl-3H-pyrazol-3-one; 2-(3,4-Dimethylphenyl)-5-methyl-1H-pyrazol-3-one; 2-(3,4-Dimethylphenyl)-5-methyl-1H-pyrazol-3(2H)-one ;