European Pharmacopoeia (EP) Reference Standard Synonym(s): 4-Isopropylantipyrine; 1,2-Dihydro-1,5-dimethyl-4-(1-methylethyl)-2-phenyl-3 H -pyrazol-3-one; 1,2-Dihydro-4-isopropyl-1,5-dimethyl-2-phenyl-3 H -pyrazol-3-one; Isopropylphenazone; Propyphenazone Empirical Formula:...