<unk>  is a crystalline substance. It is obtained by condensation of diethyl n-butylmalonate with hydrazobenzene in the presence of base. In effect, this represents the formation of the heterocyclic system by simple lactamization. File:1,2-Diphenylhydrazin.Hydrazobenzene File:Diethyl-butylmalonate skeletal.Diethyl n-butylmalonate Oxyphenbutazone, the major metabolite of<unk> , differs only in the para location of one of its phenyl groups, where a hydrogen atom is replaced by a hydroxyl group (making it 4-butyl-1-(4-hydroxyphenyl)-2-phenyl-3,5-pyrazolidinedione).
Phenylbutazone
Metolazone
Flonicamid
Butylone
Tolbutamide
Bromfenac
Acebutolol
Iodixanol