A pyrazolone derivative that is 1,2-dihydropyrazol-3-one substituted with methyl groups at N-1 and C-5 and with a phenyl group at N-2. ChEBI: Antipyrine is a pyrazolone derivative that is 1,2-dihydropyrazol-3-one substituted with methyl groups at N-1 and C-5 and with a phenyl group at N-2. It has a role as a non-narcotic analgesic, an antipyretic, a non-steroidal anti-inflammatory drug, a cyclooxygenase 3 inhibitor, a xenobiotic and an environmental contaminant.