1-Phenyl-2,3-dimethyl-4-sec-butyl-5-pyrazolon 3H-Pyrazol-3-one, 1,2-dihydro-1,5-dimethyl-4-(1-methylpropyl)-2-phenyl- 4-24-00-00148 (Beilstein Handbook Reference) 4-sec-Butylantipyrine 96974-48-0 ANTIPYRINE, 4-sec-BUTYL- BRN 0218062